mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-31 16:38:12 +00:00
Fix a variety of bugs, many of which were found by folks using fuzzing
or error injection. Also fix up how test_dummy_encryption mount option is handled for the new mount API. Finally, fix/cleanup a number of comments and ext4 Documentation files. -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEK2m5VNv+CHkogTfJ8vlZVpUNgaMFAmKuYpcACgkQ8vlZVpUN gaMXwwf8DSHJ3gI2Lo0wrzJm7KSS0C+HK29/rtLCZdxECQsZR156ZzSF3zAFKOwK Yx3RJwiFxrciUUytY/MWTyalCk+M8oW1093SfRqNNZCbZNi33acnbTqioa7INnDw snFGGEU1y0M0AUduxNWPr71P80sTyQa0ZplIc4YeR98zzMvoWgi1dvo4wNdtJNQb Gb0FtBhgP+IeK50eBlK4O0Eg5kqd0V5OeTLUYUfsWqU28ap8dHYE48I6sIdHx6az sa6b2+YRuBxJUV61FNujuVtkDgUHXtXM97kkGpywRSLjo4iFxlQvX9Ew4lBD9RDI b0YHVzK/DU9M3VfiYgzGwShCb/M68w== =NtNY -----END PGP SIGNATURE----- Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 fixes from Ted Ts'o: "Fix a variety of bugs, many of which were found by folks using fuzzing or error injection. Also fix up how test_dummy_encryption mount option is handled for the new mount API. Finally, fix/cleanup a number of comments and ext4 Documentation files" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: fix a doubled word "need" in a comment ext4: add reserved GDT blocks check ext4: make variable "count" signed ext4: correct the judgment of BUG in ext4_mb_normalize_request ext4: fix bug_on ext4_mb_use_inode_pa ext4: fix up test_dummy_encryption handling for new mount API ext4: use kmemdup() to replace kmalloc + memcpy ext4: fix super block checksum incorrect after mount ext4: improve write performance with disabled delalloc ext4: fix warning when submitting superblock in ext4_commit_super() ext4, doc: remove unnecessary escaping ext4: fix incorrect comment in ext4_bio_write_page() fs: fix jbd2_journal_try_to_free_buffers() kernel-doc comment
This commit is contained in:
commit
354c6e071b
26 changed files with 947 additions and 895 deletions
|
@ -13,8 +13,8 @@ disappeared as of Linux 3.0.
|
|||
|
||||
There are two places where extended attributes can be found. The first
|
||||
place is between the end of each inode entry and the beginning of the
|
||||
next inode entry. For example, if inode.i\_extra\_isize = 28 and
|
||||
sb.inode\_size = 256, then there are 256 - (128 + 28) = 100 bytes
|
||||
next inode entry. For example, if inode.i_extra_isize = 28 and
|
||||
sb.inode_size = 256, then there are 256 - (128 + 28) = 100 bytes
|
||||
available for in-inode extended attribute storage. The second place
|
||||
where extended attributes can be found is in the block pointed to by
|
||||
``inode.i_file_acl``. As of Linux 3.11, it is not possible for this
|
||||
|
@ -38,8 +38,8 @@ Extended attributes, when stored after the inode, have a header
|
|||
- Name
|
||||
- Description
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* - 0x0
|
||||
- \_\_le32
|
||||
- h\_magic
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||||
- __le32
|
||||
- h_magic
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||||
- Magic number for identification, 0xEA020000. This value is set by the
|
||||
Linux driver, though e2fsprogs doesn't seem to check it(?)
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||||
|
||||
|
@ -55,28 +55,28 @@ The beginning of an extended attribute block is in
|
|||
- Name
|
||||
- Description
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||||
* - 0x0
|
||||
- \_\_le32
|
||||
- h\_magic
|
||||
- __le32
|
||||
- h_magic
|
||||
- Magic number for identification, 0xEA020000.
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- h\_refcount
|
||||
- __le32
|
||||
- h_refcount
|
||||
- Reference count.
|
||||
* - 0x8
|
||||
- \_\_le32
|
||||
- h\_blocks
|
||||
- __le32
|
||||
- h_blocks
|
||||
- Number of disk blocks used.
|
||||
* - 0xC
|
||||
- \_\_le32
|
||||
- h\_hash
|
||||
- __le32
|
||||
- h_hash
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||||
- Hash value of all attributes.
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||||
* - 0x10
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||||
- \_\_le32
|
||||
- h\_checksum
|
||||
- __le32
|
||||
- h_checksum
|
||||
- Checksum of the extended attribute block.
|
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* - 0x14
|
||||
- \_\_u32
|
||||
- h\_reserved[3]
|
||||
- __u32
|
||||
- h_reserved[3]
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||||
- Zero.
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||||
|
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The checksum is calculated against the FS UUID, the 64-bit block number
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|
@ -100,46 +100,46 @@ Attributes stored inside an inode do not need be stored in sorted order.
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_u8
|
||||
- e\_name\_len
|
||||
- __u8
|
||||
- e_name_len
|
||||
- Length of name.
|
||||
* - 0x1
|
||||
- \_\_u8
|
||||
- e\_name\_index
|
||||
- __u8
|
||||
- e_name_index
|
||||
- Attribute name index. There is a discussion of this below.
|
||||
* - 0x2
|
||||
- \_\_le16
|
||||
- e\_value\_offs
|
||||
- __le16
|
||||
- e_value_offs
|
||||
- Location of this attribute's value on the disk block where it is stored.
|
||||
Multiple attributes can share the same value. For an inode attribute
|
||||
this value is relative to the start of the first entry; for a block this
|
||||
value is relative to the start of the block (i.e. the header).
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- e\_value\_inum
|
||||
- __le32
|
||||
- e_value_inum
|
||||
- The inode where the value is stored. Zero indicates the value is in the
|
||||
same block as this entry. This field is only used if the
|
||||
INCOMPAT\_EA\_INODE feature is enabled.
|
||||
INCOMPAT_EA_INODE feature is enabled.
|
||||
* - 0x8
|
||||
- \_\_le32
|
||||
- e\_value\_size
|
||||
- __le32
|
||||
- e_value_size
|
||||
- Length of attribute value.
|
||||
* - 0xC
|
||||
- \_\_le32
|
||||
- e\_hash
|
||||
- __le32
|
||||
- e_hash
|
||||
- Hash value of attribute name and attribute value. The kernel doesn't
|
||||
update the hash for in-inode attributes, so for that case this value
|
||||
must be zero, because e2fsck validates any non-zero hash regardless of
|
||||
where the xattr lives.
|
||||
* - 0x10
|
||||
- char
|
||||
- e\_name[e\_name\_len]
|
||||
- e_name[e_name_len]
|
||||
- Attribute name. Does not include trailing NULL.
|
||||
|
||||
Attribute values can follow the end of the entry table. There appears to
|
||||
be a requirement that they be aligned to 4-byte boundaries. The values
|
||||
are stored starting at the end of the block and grow towards the
|
||||
xattr\_header/xattr\_entry table. When the two collide, the overflow is
|
||||
xattr_header/xattr_entry table. When the two collide, the overflow is
|
||||
put into a separate disk block. If the disk block fills up, the
|
||||
filesystem returns -ENOSPC.
|
||||
|
||||
|
@ -167,15 +167,15 @@ the key name. Here is a map of name index values to key prefixes:
|
|||
* - 1
|
||||
- “user.”
|
||||
* - 2
|
||||
- “system.posix\_acl\_access”
|
||||
- “system.posix_acl_access”
|
||||
* - 3
|
||||
- “system.posix\_acl\_default”
|
||||
- “system.posix_acl_default”
|
||||
* - 4
|
||||
- “trusted.”
|
||||
* - 6
|
||||
- “security.”
|
||||
* - 7
|
||||
- “system.” (inline\_data only?)
|
||||
- “system.” (inline_data only?)
|
||||
* - 8
|
||||
- “system.richacl” (SuSE kernels only?)
|
||||
|
||||
|
|
|
@ -23,7 +23,7 @@ means that a block group addresses 32 gigabytes instead of 128 megabytes,
|
|||
also shrinking the amount of file system overhead for metadata.
|
||||
|
||||
The administrator can set a block cluster size at mkfs time (which is
|
||||
stored in the s\_log\_cluster\_size field in the superblock); from then
|
||||
stored in the s_log_cluster_size field in the superblock); from then
|
||||
on, the block bitmaps track clusters, not individual blocks. This means
|
||||
that block groups can be several gigabytes in size (instead of just
|
||||
128MiB); however, the minimum allocation unit becomes a cluster, not a
|
||||
|
|
|
@ -9,15 +9,15 @@ group.
|
|||
The inode bitmap records which entries in the inode table are in use.
|
||||
|
||||
As with most bitmaps, one bit represents the usage status of one data
|
||||
block or inode table entry. This implies a block group size of 8 \*
|
||||
number\_of\_bytes\_in\_a\_logical\_block.
|
||||
block or inode table entry. This implies a block group size of 8 *
|
||||
number_of_bytes_in_a_logical_block.
|
||||
|
||||
NOTE: If ``BLOCK_UNINIT`` is set for a given block group, various parts
|
||||
of the kernel and e2fsprogs code pretends that the block bitmap contains
|
||||
zeros (i.e. all blocks in the group are free). However, it is not
|
||||
necessarily the case that no blocks are in use -- if ``meta_bg`` is set,
|
||||
the bitmaps and group descriptor live inside the group. Unfortunately,
|
||||
ext2fs\_test\_block\_bitmap2() will return '0' for those locations,
|
||||
ext2fs_test_block_bitmap2() will return '0' for those locations,
|
||||
which produces confusing debugfs output.
|
||||
|
||||
Inode Table
|
||||
|
|
|
@ -56,39 +56,39 @@ established that the super block and the group descriptor table, if
|
|||
present, will be at the beginning of the block group. The bitmaps and
|
||||
the inode table can be anywhere, and it is quite possible for the
|
||||
bitmaps to come after the inode table, or for both to be in different
|
||||
groups (flex\_bg). Leftover space is used for file data blocks, indirect
|
||||
groups (flex_bg). Leftover space is used for file data blocks, indirect
|
||||
block maps, extent tree blocks, and extended attributes.
|
||||
|
||||
Flexible Block Groups
|
||||
---------------------
|
||||
|
||||
Starting in ext4, there is a new feature called flexible block groups
|
||||
(flex\_bg). In a flex\_bg, several block groups are tied together as one
|
||||
(flex_bg). In a flex_bg, several block groups are tied together as one
|
||||
logical block group; the bitmap spaces and the inode table space in the
|
||||
first block group of the flex\_bg are expanded to include the bitmaps
|
||||
and inode tables of all other block groups in the flex\_bg. For example,
|
||||
if the flex\_bg size is 4, then group 0 will contain (in order) the
|
||||
first block group of the flex_bg are expanded to include the bitmaps
|
||||
and inode tables of all other block groups in the flex_bg. For example,
|
||||
if the flex_bg size is 4, then group 0 will contain (in order) the
|
||||
superblock, group descriptors, data block bitmaps for groups 0-3, inode
|
||||
bitmaps for groups 0-3, inode tables for groups 0-3, and the remaining
|
||||
space in group 0 is for file data. The effect of this is to group the
|
||||
block group metadata close together for faster loading, and to enable
|
||||
large files to be continuous on disk. Backup copies of the superblock
|
||||
and group descriptors are always at the beginning of block groups, even
|
||||
if flex\_bg is enabled. The number of block groups that make up a
|
||||
flex\_bg is given by 2 ^ ``sb.s_log_groups_per_flex``.
|
||||
if flex_bg is enabled. The number of block groups that make up a
|
||||
flex_bg is given by 2 ^ ``sb.s_log_groups_per_flex``.
|
||||
|
||||
Meta Block Groups
|
||||
-----------------
|
||||
|
||||
Without the option META\_BG, for safety concerns, all block group
|
||||
Without the option META_BG, for safety concerns, all block group
|
||||
descriptors copies are kept in the first block group. Given the default
|
||||
128MiB(2^27 bytes) block group size and 64-byte group descriptors, ext4
|
||||
can have at most 2^27/64 = 2^21 block groups. This limits the entire
|
||||
filesystem size to 2^21 * 2^27 = 2^48bytes or 256TiB.
|
||||
|
||||
The solution to this problem is to use the metablock group feature
|
||||
(META\_BG), which is already in ext3 for all 2.6 releases. With the
|
||||
META\_BG feature, ext4 filesystems are partitioned into many metablock
|
||||
(META_BG), which is already in ext3 for all 2.6 releases. With the
|
||||
META_BG feature, ext4 filesystems are partitioned into many metablock
|
||||
groups. Each metablock group is a cluster of block groups whose group
|
||||
descriptor structures can be stored in a single disk block. For ext4
|
||||
filesystems with 4 KB block size, a single metablock group partition
|
||||
|
@ -110,7 +110,7 @@ bytes, a meta-block group contains 32 block groups for filesystems with
|
|||
a 1KB block size, and 128 block groups for filesystems with a 4KB
|
||||
blocksize. Filesystems can either be created using this new block group
|
||||
descriptor layout, or existing filesystems can be resized on-line, and
|
||||
the field s\_first\_meta\_bg in the superblock will indicate the first
|
||||
the field s_first_meta_bg in the superblock will indicate the first
|
||||
block group using this new layout.
|
||||
|
||||
Please see an important note about ``BLOCK_UNINIT`` in the section about
|
||||
|
@ -121,15 +121,15 @@ Lazy Block Group Initialization
|
|||
|
||||
A new feature for ext4 are three block group descriptor flags that
|
||||
enable mkfs to skip initializing other parts of the block group
|
||||
metadata. Specifically, the INODE\_UNINIT and BLOCK\_UNINIT flags mean
|
||||
metadata. Specifically, the INODE_UNINIT and BLOCK_UNINIT flags mean
|
||||
that the inode and block bitmaps for that group can be calculated and
|
||||
therefore the on-disk bitmap blocks are not initialized. This is
|
||||
generally the case for an empty block group or a block group containing
|
||||
only fixed-location block group metadata. The INODE\_ZEROED flag means
|
||||
only fixed-location block group metadata. The INODE_ZEROED flag means
|
||||
that the inode table has been initialized; mkfs will unset this flag and
|
||||
rely on the kernel to initialize the inode tables in the background.
|
||||
|
||||
By not writing zeroes to the bitmaps and inode table, mkfs time is
|
||||
reduced considerably. Note the feature flag is RO\_COMPAT\_GDT\_CSUM,
|
||||
but the dumpe2fs output prints this as “uninit\_bg”. They are the same
|
||||
reduced considerably. Note the feature flag is RO_COMPAT_GDT_CSUM,
|
||||
but the dumpe2fs output prints this as “uninit_bg”. They are the same
|
||||
thing.
|
||||
|
|
|
@ -1,7 +1,7 @@
|
|||
.. SPDX-License-Identifier: GPL-2.0
|
||||
|
||||
+---------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|
||||
| i.i\_block Offset | Where It Points |
|
||||
| i.i_block Offset | Where It Points |
|
||||
+=====================+==============================================================================================================================================================================================================================+
|
||||
| 0 to 11 | Direct map to file blocks 0 to 11. |
|
||||
+---------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|
||||
|
|
|
@ -4,7 +4,7 @@ Checksums
|
|||
---------
|
||||
|
||||
Starting in early 2012, metadata checksums were added to all major ext4
|
||||
and jbd2 data structures. The associated feature flag is metadata\_csum.
|
||||
and jbd2 data structures. The associated feature flag is metadata_csum.
|
||||
The desired checksum algorithm is indicated in the superblock, though as
|
||||
of October 2012 the only supported algorithm is crc32c. Some data
|
||||
structures did not have space to fit a full 32-bit checksum, so only the
|
||||
|
@ -20,7 +20,7 @@ encounters directory blocks that lack sufficient empty space to add a
|
|||
checksum, it will request that you run ``e2fsck -D`` to have the
|
||||
directories rebuilt with checksums. This has the added benefit of
|
||||
removing slack space from the directory files and rebalancing the htree
|
||||
indexes. If you \_ignore\_ this step, your directories will not be
|
||||
indexes. If you _ignore_ this step, your directories will not be
|
||||
protected by a checksum!
|
||||
|
||||
The following table describes the data elements that go into each type
|
||||
|
@ -35,39 +35,39 @@ of checksum. The checksum function is whatever the superblock describes
|
|||
- Length
|
||||
- Ingredients
|
||||
* - Superblock
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- The entire superblock up to the checksum field. The UUID lives inside
|
||||
the superblock.
|
||||
* - MMP
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- UUID + the entire MMP block up to the checksum field.
|
||||
* - Extended Attributes
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- UUID + the entire extended attribute block. The checksum field is set to
|
||||
zero.
|
||||
* - Directory Entries
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- UUID + inode number + inode generation + the directory block up to the
|
||||
fake entry enclosing the checksum field.
|
||||
* - HTREE Nodes
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- UUID + inode number + inode generation + all valid extents + HTREE tail.
|
||||
The checksum field is set to zero.
|
||||
* - Extents
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- UUID + inode number + inode generation + the entire extent block up to
|
||||
the checksum field.
|
||||
* - Bitmaps
|
||||
- \_\_le32 or \_\_le16
|
||||
- __le32 or __le16
|
||||
- UUID + the entire bitmap. Checksums are stored in the group descriptor,
|
||||
and truncated if the group descriptor size is 32 bytes (i.e. ^64bit)
|
||||
* - Inodes
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- UUID + inode number + inode generation + the entire inode. The checksum
|
||||
field is set to zero. Each inode has its own checksum.
|
||||
* - Group Descriptors
|
||||
- \_\_le16
|
||||
- If metadata\_csum, then UUID + group number + the entire descriptor;
|
||||
else if gdt\_csum, then crc16(UUID + group number + the entire
|
||||
- __le16
|
||||
- If metadata_csum, then UUID + group number + the entire descriptor;
|
||||
else if gdt_csum, then crc16(UUID + group number + the entire
|
||||
descriptor). In all cases, only the lower 16 bits are stored.
|
||||
|
||||
|
|
|
@ -42,24 +42,24 @@ is at most 263 bytes long, though on disk you'll need to reference
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- inode
|
||||
- Number of the inode that this directory entry points to.
|
||||
* - 0x4
|
||||
- \_\_le16
|
||||
- rec\_len
|
||||
- __le16
|
||||
- rec_len
|
||||
- Length of this directory entry. Must be a multiple of 4.
|
||||
* - 0x6
|
||||
- \_\_le16
|
||||
- name\_len
|
||||
- __le16
|
||||
- name_len
|
||||
- Length of the file name.
|
||||
* - 0x8
|
||||
- char
|
||||
- name[EXT4\_NAME\_LEN]
|
||||
- name[EXT4_NAME_LEN]
|
||||
- File name.
|
||||
|
||||
Since file names cannot be longer than 255 bytes, the new directory
|
||||
entry format shortens the name\_len field and uses the space for a file
|
||||
entry format shortens the name_len field and uses the space for a file
|
||||
type flag, probably to avoid having to load every inode during directory
|
||||
tree traversal. This format is ``ext4_dir_entry_2``, which is at most
|
||||
263 bytes long, though on disk you'll need to reference
|
||||
|
@ -74,24 +74,24 @@ tree traversal. This format is ``ext4_dir_entry_2``, which is at most
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- inode
|
||||
- Number of the inode that this directory entry points to.
|
||||
* - 0x4
|
||||
- \_\_le16
|
||||
- rec\_len
|
||||
- __le16
|
||||
- rec_len
|
||||
- Length of this directory entry.
|
||||
* - 0x6
|
||||
- \_\_u8
|
||||
- name\_len
|
||||
- __u8
|
||||
- name_len
|
||||
- Length of the file name.
|
||||
* - 0x7
|
||||
- \_\_u8
|
||||
- file\_type
|
||||
- __u8
|
||||
- file_type
|
||||
- File type code, see ftype_ table below.
|
||||
* - 0x8
|
||||
- char
|
||||
- name[EXT4\_NAME\_LEN]
|
||||
- name[EXT4_NAME_LEN]
|
||||
- File name.
|
||||
|
||||
.. _ftype:
|
||||
|
@ -137,19 +137,19 @@ entry uses this extension, it may be up to 271 bytes.
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- hash
|
||||
- The hash of the directory name
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- minor\_hash
|
||||
- __le32
|
||||
- minor_hash
|
||||
- The minor hash of the directory name
|
||||
|
||||
|
||||
In order to add checksums to these classic directory blocks, a phony
|
||||
``struct ext4_dir_entry`` is placed at the end of each leaf block to
|
||||
hold the checksum. The directory entry is 12 bytes long. The inode
|
||||
number and name\_len fields are set to zero to fool old software into
|
||||
number and name_len fields are set to zero to fool old software into
|
||||
ignoring an apparently empty directory entry, and the checksum is stored
|
||||
in the place where the name normally goes. The structure is
|
||||
``struct ext4_dir_entry_tail``:
|
||||
|
@ -163,24 +163,24 @@ in the place where the name normally goes. The structure is
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- det\_reserved\_zero1
|
||||
- __le32
|
||||
- det_reserved_zero1
|
||||
- Inode number, which must be zero.
|
||||
* - 0x4
|
||||
- \_\_le16
|
||||
- det\_rec\_len
|
||||
- __le16
|
||||
- det_rec_len
|
||||
- Length of this directory entry, which must be 12.
|
||||
* - 0x6
|
||||
- \_\_u8
|
||||
- det\_reserved\_zero2
|
||||
- __u8
|
||||
- det_reserved_zero2
|
||||
- Length of the file name, which must be zero.
|
||||
* - 0x7
|
||||
- \_\_u8
|
||||
- det\_reserved\_ft
|
||||
- __u8
|
||||
- det_reserved_ft
|
||||
- File type, which must be 0xDE.
|
||||
* - 0x8
|
||||
- \_\_le32
|
||||
- det\_checksum
|
||||
- __le32
|
||||
- det_checksum
|
||||
- Directory leaf block checksum.
|
||||
|
||||
The leaf directory block checksum is calculated against the FS UUID, the
|
||||
|
@ -194,7 +194,7 @@ Hash Tree Directories
|
|||
A linear array of directory entries isn't great for performance, so a
|
||||
new feature was added to ext3 to provide a faster (but peculiar)
|
||||
balanced tree keyed off a hash of the directory entry name. If the
|
||||
EXT4\_INDEX\_FL (0x1000) flag is set in the inode, this directory uses a
|
||||
EXT4_INDEX_FL (0x1000) flag is set in the inode, this directory uses a
|
||||
hashed btree (htree) to organize and find directory entries. For
|
||||
backwards read-only compatibility with ext2, this tree is actually
|
||||
hidden inside the directory file, masquerading as “empty” directory data
|
||||
|
@ -206,14 +206,14 @@ rest of the directory block is empty so that it moves on.
|
|||
The root of the tree always lives in the first data block of the
|
||||
directory. By ext2 custom, the '.' and '..' entries must appear at the
|
||||
beginning of this first block, so they are put here as two
|
||||
``struct ext4_dir_entry_2``\ s and not stored in the tree. The rest of
|
||||
``struct ext4_dir_entry_2`` s and not stored in the tree. The rest of
|
||||
the root node contains metadata about the tree and finally a hash->block
|
||||
map to find nodes that are lower in the htree. If
|
||||
``dx_root.info.indirect_levels`` is non-zero then the htree has two
|
||||
levels; the data block pointed to by the root node's map is an interior
|
||||
node, which is indexed by a minor hash. Interior nodes in this tree
|
||||
contains a zeroed out ``struct ext4_dir_entry_2`` followed by a
|
||||
minor\_hash->block map to find leafe nodes. Leaf nodes contain a linear
|
||||
minor_hash->block map to find leafe nodes. Leaf nodes contain a linear
|
||||
array of all ``struct ext4_dir_entry_2``; all of these entries
|
||||
(presumably) hash to the same value. If there is an overflow, the
|
||||
entries simply overflow into the next leaf node, and the
|
||||
|
@ -245,83 +245,83 @@ of a data block:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- dot.inode
|
||||
- inode number of this directory.
|
||||
* - 0x4
|
||||
- \_\_le16
|
||||
- dot.rec\_len
|
||||
- __le16
|
||||
- dot.rec_len
|
||||
- Length of this record, 12.
|
||||
* - 0x6
|
||||
- u8
|
||||
- dot.name\_len
|
||||
- dot.name_len
|
||||
- Length of the name, 1.
|
||||
* - 0x7
|
||||
- u8
|
||||
- dot.file\_type
|
||||
- dot.file_type
|
||||
- File type of this entry, 0x2 (directory) (if the feature flag is set).
|
||||
* - 0x8
|
||||
- char
|
||||
- dot.name[4]
|
||||
- “.\\0\\0\\0”
|
||||
- “.\0\0\0”
|
||||
* - 0xC
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- dotdot.inode
|
||||
- inode number of parent directory.
|
||||
* - 0x10
|
||||
- \_\_le16
|
||||
- dotdot.rec\_len
|
||||
- block\_size - 12. The record length is long enough to cover all htree
|
||||
- __le16
|
||||
- dotdot.rec_len
|
||||
- block_size - 12. The record length is long enough to cover all htree
|
||||
data.
|
||||
* - 0x12
|
||||
- u8
|
||||
- dotdot.name\_len
|
||||
- dotdot.name_len
|
||||
- Length of the name, 2.
|
||||
* - 0x13
|
||||
- u8
|
||||
- dotdot.file\_type
|
||||
- dotdot.file_type
|
||||
- File type of this entry, 0x2 (directory) (if the feature flag is set).
|
||||
* - 0x14
|
||||
- char
|
||||
- dotdot\_name[4]
|
||||
- “..\\0\\0”
|
||||
- dotdot_name[4]
|
||||
- “..\0\0”
|
||||
* - 0x18
|
||||
- \_\_le32
|
||||
- struct dx\_root\_info.reserved\_zero
|
||||
- __le32
|
||||
- struct dx_root_info.reserved_zero
|
||||
- Zero.
|
||||
* - 0x1C
|
||||
- u8
|
||||
- struct dx\_root\_info.hash\_version
|
||||
- struct dx_root_info.hash_version
|
||||
- Hash type, see dirhash_ table below.
|
||||
* - 0x1D
|
||||
- u8
|
||||
- struct dx\_root\_info.info\_length
|
||||
- struct dx_root_info.info_length
|
||||
- Length of the tree information, 0x8.
|
||||
* - 0x1E
|
||||
- u8
|
||||
- struct dx\_root\_info.indirect\_levels
|
||||
- Depth of the htree. Cannot be larger than 3 if the INCOMPAT\_LARGEDIR
|
||||
- struct dx_root_info.indirect_levels
|
||||
- Depth of the htree. Cannot be larger than 3 if the INCOMPAT_LARGEDIR
|
||||
feature is set; cannot be larger than 2 otherwise.
|
||||
* - 0x1F
|
||||
- u8
|
||||
- struct dx\_root\_info.unused\_flags
|
||||
- struct dx_root_info.unused_flags
|
||||
-
|
||||
* - 0x20
|
||||
- \_\_le16
|
||||
- __le16
|
||||
- limit
|
||||
- Maximum number of dx\_entries that can follow this header, plus 1 for
|
||||
- Maximum number of dx_entries that can follow this header, plus 1 for
|
||||
the header itself.
|
||||
* - 0x22
|
||||
- \_\_le16
|
||||
- __le16
|
||||
- count
|
||||
- Actual number of dx\_entries that follow this header, plus 1 for the
|
||||
- Actual number of dx_entries that follow this header, plus 1 for the
|
||||
header itself.
|
||||
* - 0x24
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- block
|
||||
- The block number (within the directory file) that goes with hash=0.
|
||||
* - 0x28
|
||||
- struct dx\_entry
|
||||
- struct dx_entry
|
||||
- entries[0]
|
||||
- As many 8-byte ``struct dx_entry`` as fits in the rest of the data block.
|
||||
|
||||
|
@ -362,38 +362,38 @@ also the full length of a data block:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- fake.inode
|
||||
- Zero, to make it look like this entry is not in use.
|
||||
* - 0x4
|
||||
- \_\_le16
|
||||
- fake.rec\_len
|
||||
- The size of the block, in order to hide all of the dx\_node data.
|
||||
- __le16
|
||||
- fake.rec_len
|
||||
- The size of the block, in order to hide all of the dx_node data.
|
||||
* - 0x6
|
||||
- u8
|
||||
- name\_len
|
||||
- name_len
|
||||
- Zero. There is no name for this “unused” directory entry.
|
||||
* - 0x7
|
||||
- u8
|
||||
- file\_type
|
||||
- file_type
|
||||
- Zero. There is no file type for this “unused” directory entry.
|
||||
* - 0x8
|
||||
- \_\_le16
|
||||
- __le16
|
||||
- limit
|
||||
- Maximum number of dx\_entries that can follow this header, plus 1 for
|
||||
- Maximum number of dx_entries that can follow this header, plus 1 for
|
||||
the header itself.
|
||||
* - 0xA
|
||||
- \_\_le16
|
||||
- __le16
|
||||
- count
|
||||
- Actual number of dx\_entries that follow this header, plus 1 for the
|
||||
- Actual number of dx_entries that follow this header, plus 1 for the
|
||||
header itself.
|
||||
* - 0xE
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- block
|
||||
- The block number (within the directory file) that goes with the lowest
|
||||
hash value of this block. This value is stored in the parent block.
|
||||
* - 0x12
|
||||
- struct dx\_entry
|
||||
- struct dx_entry
|
||||
- entries[0]
|
||||
- As many 8-byte ``struct dx_entry`` as fits in the rest of the data block.
|
||||
|
||||
|
@ -410,11 +410,11 @@ long:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- hash
|
||||
- Hash code.
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- __le32
|
||||
- block
|
||||
- Block number (within the directory file, not filesystem blocks) of the
|
||||
next node in the htree.
|
||||
|
@ -423,13 +423,13 @@ long:
|
|||
author.)
|
||||
|
||||
If metadata checksums are enabled, the last 8 bytes of the directory
|
||||
block (precisely the length of one dx\_entry) are used to store a
|
||||
block (precisely the length of one dx_entry) are used to store a
|
||||
``struct dx_tail``, which contains the checksum. The ``limit`` and
|
||||
``count`` entries in the dx\_root/dx\_node structures are adjusted as
|
||||
necessary to fit the dx\_tail into the block. If there is no space for
|
||||
the dx\_tail, the user is notified to run e2fsck -D to rebuild the
|
||||
``count`` entries in the dx_root/dx_node structures are adjusted as
|
||||
necessary to fit the dx_tail into the block. If there is no space for
|
||||
the dx_tail, the user is notified to run e2fsck -D to rebuild the
|
||||
directory index (which will ensure that there's space for the checksum.
|
||||
The dx\_tail structure is 8 bytes long and looks like this:
|
||||
The dx_tail structure is 8 bytes long and looks like this:
|
||||
|
||||
.. list-table::
|
||||
:widths: 8 8 24 40
|
||||
|
@ -441,13 +441,13 @@ The dx\_tail structure is 8 bytes long and looks like this:
|
|||
- Description
|
||||
* - 0x0
|
||||
- u32
|
||||
- dt\_reserved
|
||||
- dt_reserved
|
||||
- Zero.
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- dt\_checksum
|
||||
- __le32
|
||||
- dt_checksum
|
||||
- Checksum of the htree directory block.
|
||||
|
||||
The checksum is calculated against the FS UUID, the htree index header
|
||||
(dx\_root or dx\_node), all of the htree indices (dx\_entry) that are in
|
||||
use, and the tail block (dx\_tail).
|
||||
(dx_root or dx_node), all of the htree indices (dx_entry) that are in
|
||||
use, and the tail block (dx_tail).
|
||||
|
|
|
@ -5,14 +5,14 @@ Large Extended Attribute Values
|
|||
|
||||
To enable ext4 to store extended attribute values that do not fit in the
|
||||
inode or in the single extended attribute block attached to an inode,
|
||||
the EA\_INODE feature allows us to store the value in the data blocks of
|
||||
the EA_INODE feature allows us to store the value in the data blocks of
|
||||
a regular file inode. This “EA inode” is linked only from the extended
|
||||
attribute name index and must not appear in a directory entry. The
|
||||
inode's i\_atime field is used to store a checksum of the xattr value;
|
||||
and i\_ctime/i\_version store a 64-bit reference count, which enables
|
||||
inode's i_atime field is used to store a checksum of the xattr value;
|
||||
and i_ctime/i_version store a 64-bit reference count, which enables
|
||||
sharing of large xattr values between multiple owning inodes. For
|
||||
backward compatibility with older versions of this feature, the
|
||||
i\_mtime/i\_generation *may* store a back-reference to the inode number
|
||||
and i\_generation of the **one** owning inode (in cases where the EA
|
||||
i_mtime/i_generation *may* store a back-reference to the inode number
|
||||
and i_generation of the **one** owning inode (in cases where the EA
|
||||
inode is not referenced by multiple inodes) to verify that the EA inode
|
||||
is the correct one being accessed.
|
||||
|
|
|
@ -7,34 +7,34 @@ Each block group on the filesystem has one of these descriptors
|
|||
associated with it. As noted in the Layout section above, the group
|
||||
descriptors (if present) are the second item in the block group. The
|
||||
standard configuration is for each block group to contain a full copy of
|
||||
the block group descriptor table unless the sparse\_super feature flag
|
||||
the block group descriptor table unless the sparse_super feature flag
|
||||
is set.
|
||||
|
||||
Notice how the group descriptor records the location of both bitmaps and
|
||||
the inode table (i.e. they can float). This means that within a block
|
||||
group, the only data structures with fixed locations are the superblock
|
||||
and the group descriptor table. The flex\_bg mechanism uses this
|
||||
and the group descriptor table. The flex_bg mechanism uses this
|
||||
property to group several block groups into a flex group and lay out all
|
||||
of the groups' bitmaps and inode tables into one long run in the first
|
||||
group of the flex group.
|
||||
|
||||
If the meta\_bg feature flag is set, then several block groups are
|
||||
grouped together into a meta group. Note that in the meta\_bg case,
|
||||
If the meta_bg feature flag is set, then several block groups are
|
||||
grouped together into a meta group. Note that in the meta_bg case,
|
||||
however, the first and last two block groups within the larger meta
|
||||
group contain only group descriptors for the groups inside the meta
|
||||
group.
|
||||
|
||||
flex\_bg and meta\_bg do not appear to be mutually exclusive features.
|
||||
flex_bg and meta_bg do not appear to be mutually exclusive features.
|
||||
|
||||
In ext2, ext3, and ext4 (when the 64bit feature is not enabled), the
|
||||
block group descriptor was only 32 bytes long and therefore ends at
|
||||
bg\_checksum. On an ext4 filesystem with the 64bit feature enabled, the
|
||||
bg_checksum. On an ext4 filesystem with the 64bit feature enabled, the
|
||||
block group descriptor expands to at least the 64 bytes described below;
|
||||
the size is stored in the superblock.
|
||||
|
||||
If gdt\_csum is set and metadata\_csum is not set, the block group
|
||||
If gdt_csum is set and metadata_csum is not set, the block group
|
||||
checksum is the crc16 of the FS UUID, the group number, and the group
|
||||
descriptor structure. If metadata\_csum is set, then the block group
|
||||
descriptor structure. If metadata_csum is set, then the block group
|
||||
checksum is the lower 16 bits of the checksum of the FS UUID, the group
|
||||
number, and the group descriptor structure. Both block and inode bitmap
|
||||
checksums are calculated against the FS UUID, the group number, and the
|
||||
|
@ -51,59 +51,59 @@ The block group descriptor is laid out in ``struct ext4_group_desc``.
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- bg\_block\_bitmap\_lo
|
||||
- __le32
|
||||
- bg_block_bitmap_lo
|
||||
- Lower 32-bits of location of block bitmap.
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- bg\_inode\_bitmap\_lo
|
||||
- __le32
|
||||
- bg_inode_bitmap_lo
|
||||
- Lower 32-bits of location of inode bitmap.
|
||||
* - 0x8
|
||||
- \_\_le32
|
||||
- bg\_inode\_table\_lo
|
||||
- __le32
|
||||
- bg_inode_table_lo
|
||||
- Lower 32-bits of location of inode table.
|
||||
* - 0xC
|
||||
- \_\_le16
|
||||
- bg\_free\_blocks\_count\_lo
|
||||
- __le16
|
||||
- bg_free_blocks_count_lo
|
||||
- Lower 16-bits of free block count.
|
||||
* - 0xE
|
||||
- \_\_le16
|
||||
- bg\_free\_inodes\_count\_lo
|
||||
- __le16
|
||||
- bg_free_inodes_count_lo
|
||||
- Lower 16-bits of free inode count.
|
||||
* - 0x10
|
||||
- \_\_le16
|
||||
- bg\_used\_dirs\_count\_lo
|
||||
- __le16
|
||||
- bg_used_dirs_count_lo
|
||||
- Lower 16-bits of directory count.
|
||||
* - 0x12
|
||||
- \_\_le16
|
||||
- bg\_flags
|
||||
- __le16
|
||||
- bg_flags
|
||||
- Block group flags. See the bgflags_ table below.
|
||||
* - 0x14
|
||||
- \_\_le32
|
||||
- bg\_exclude\_bitmap\_lo
|
||||
- __le32
|
||||
- bg_exclude_bitmap_lo
|
||||
- Lower 32-bits of location of snapshot exclusion bitmap.
|
||||
* - 0x18
|
||||
- \_\_le16
|
||||
- bg\_block\_bitmap\_csum\_lo
|
||||
- __le16
|
||||
- bg_block_bitmap_csum_lo
|
||||
- Lower 16-bits of the block bitmap checksum.
|
||||
* - 0x1A
|
||||
- \_\_le16
|
||||
- bg\_inode\_bitmap\_csum\_lo
|
||||
- __le16
|
||||
- bg_inode_bitmap_csum_lo
|
||||
- Lower 16-bits of the inode bitmap checksum.
|
||||
* - 0x1C
|
||||
- \_\_le16
|
||||
- bg\_itable\_unused\_lo
|
||||
- __le16
|
||||
- bg_itable_unused_lo
|
||||
- Lower 16-bits of unused inode count. If set, we needn't scan past the
|
||||
``(sb.s_inodes_per_group - gdt.bg_itable_unused)``\ th entry in the
|
||||
``(sb.s_inodes_per_group - gdt.bg_itable_unused)`` th entry in the
|
||||
inode table for this group.
|
||||
* - 0x1E
|
||||
- \_\_le16
|
||||
- bg\_checksum
|
||||
- Group descriptor checksum; crc16(sb\_uuid+group\_num+bg\_desc) if the
|
||||
RO\_COMPAT\_GDT\_CSUM feature is set, or
|
||||
crc32c(sb\_uuid+group\_num+bg\_desc) & 0xFFFF if the
|
||||
RO\_COMPAT\_METADATA\_CSUM feature is set. The bg\_checksum
|
||||
field in bg\_desc is skipped when calculating crc16 checksum,
|
||||
- __le16
|
||||
- bg_checksum
|
||||
- Group descriptor checksum; crc16(sb_uuid+group_num+bg_desc) if the
|
||||
RO_COMPAT_GDT_CSUM feature is set, or
|
||||
crc32c(sb_uuid+group_num+bg_desc) & 0xFFFF if the
|
||||
RO_COMPAT_METADATA_CSUM feature is set. The bg_checksum
|
||||
field in bg_desc is skipped when calculating crc16 checksum,
|
||||
and set to zero if crc32c checksum is used.
|
||||
* -
|
||||
-
|
||||
|
@ -111,48 +111,48 @@ The block group descriptor is laid out in ``struct ext4_group_desc``.
|
|||
- These fields only exist if the 64bit feature is enabled and s_desc_size
|
||||
> 32.
|
||||
* - 0x20
|
||||
- \_\_le32
|
||||
- bg\_block\_bitmap\_hi
|
||||
- __le32
|
||||
- bg_block_bitmap_hi
|
||||
- Upper 32-bits of location of block bitmap.
|
||||
* - 0x24
|
||||
- \_\_le32
|
||||
- bg\_inode\_bitmap\_hi
|
||||
- __le32
|
||||
- bg_inode_bitmap_hi
|
||||
- Upper 32-bits of location of inodes bitmap.
|
||||
* - 0x28
|
||||
- \_\_le32
|
||||
- bg\_inode\_table\_hi
|
||||
- __le32
|
||||
- bg_inode_table_hi
|
||||
- Upper 32-bits of location of inodes table.
|
||||
* - 0x2C
|
||||
- \_\_le16
|
||||
- bg\_free\_blocks\_count\_hi
|
||||
- __le16
|
||||
- bg_free_blocks_count_hi
|
||||
- Upper 16-bits of free block count.
|
||||
* - 0x2E
|
||||
- \_\_le16
|
||||
- bg\_free\_inodes\_count\_hi
|
||||
- __le16
|
||||
- bg_free_inodes_count_hi
|
||||
- Upper 16-bits of free inode count.
|
||||
* - 0x30
|
||||
- \_\_le16
|
||||
- bg\_used\_dirs\_count\_hi
|
||||
- __le16
|
||||
- bg_used_dirs_count_hi
|
||||
- Upper 16-bits of directory count.
|
||||
* - 0x32
|
||||
- \_\_le16
|
||||
- bg\_itable\_unused\_hi
|
||||
- __le16
|
||||
- bg_itable_unused_hi
|
||||
- Upper 16-bits of unused inode count.
|
||||
* - 0x34
|
||||
- \_\_le32
|
||||
- bg\_exclude\_bitmap\_hi
|
||||
- __le32
|
||||
- bg_exclude_bitmap_hi
|
||||
- Upper 32-bits of location of snapshot exclusion bitmap.
|
||||
* - 0x38
|
||||
- \_\_le16
|
||||
- bg\_block\_bitmap\_csum\_hi
|
||||
- __le16
|
||||
- bg_block_bitmap_csum_hi
|
||||
- Upper 16-bits of the block bitmap checksum.
|
||||
* - 0x3A
|
||||
- \_\_le16
|
||||
- bg\_inode\_bitmap\_csum\_hi
|
||||
- __le16
|
||||
- bg_inode_bitmap_csum_hi
|
||||
- Upper 16-bits of the inode bitmap checksum.
|
||||
* - 0x3C
|
||||
- \_\_u32
|
||||
- bg\_reserved
|
||||
- __u32
|
||||
- bg_reserved
|
||||
- Padding to 64 bytes.
|
||||
|
||||
.. _bgflags:
|
||||
|
@ -166,8 +166,8 @@ Block group flags can be any combination of the following:
|
|||
* - Value
|
||||
- Description
|
||||
* - 0x1
|
||||
- inode table and bitmap are not initialized (EXT4\_BG\_INODE\_UNINIT).
|
||||
- inode table and bitmap are not initialized (EXT4_BG_INODE_UNINIT).
|
||||
* - 0x2
|
||||
- block bitmap is not initialized (EXT4\_BG\_BLOCK\_UNINIT).
|
||||
- block bitmap is not initialized (EXT4_BG_BLOCK_UNINIT).
|
||||
* - 0x4
|
||||
- inode table is zeroed (EXT4\_BG\_INODE\_ZEROED).
|
||||
- inode table is zeroed (EXT4_BG_INODE_ZEROED).
|
||||
|
|
|
@ -1,6 +1,6 @@
|
|||
.. SPDX-License-Identifier: GPL-2.0
|
||||
|
||||
The Contents of inode.i\_block
|
||||
The Contents of inode.i_block
|
||||
------------------------------
|
||||
|
||||
Depending on the type of file an inode describes, the 60 bytes of
|
||||
|
@ -47,7 +47,7 @@ In ext4, the file to logical block map has been replaced with an extent
|
|||
tree. Under the old scheme, allocating a contiguous run of 1,000 blocks
|
||||
requires an indirect block to map all 1,000 entries; with extents, the
|
||||
mapping is reduced to a single ``struct ext4_extent`` with
|
||||
``ee_len = 1000``. If flex\_bg is enabled, it is possible to allocate
|
||||
``ee_len = 1000``. If flex_bg is enabled, it is possible to allocate
|
||||
very large files with a single extent, at a considerable reduction in
|
||||
metadata block use, and some improvement in disk efficiency. The inode
|
||||
must have the extents flag (0x80000) flag set for this feature to be in
|
||||
|
@ -76,28 +76,28 @@ which is 12 bytes long:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le16
|
||||
- eh\_magic
|
||||
- __le16
|
||||
- eh_magic
|
||||
- Magic number, 0xF30A.
|
||||
* - 0x2
|
||||
- \_\_le16
|
||||
- eh\_entries
|
||||
- __le16
|
||||
- eh_entries
|
||||
- Number of valid entries following the header.
|
||||
* - 0x4
|
||||
- \_\_le16
|
||||
- eh\_max
|
||||
- __le16
|
||||
- eh_max
|
||||
- Maximum number of entries that could follow the header.
|
||||
* - 0x6
|
||||
- \_\_le16
|
||||
- eh\_depth
|
||||
- __le16
|
||||
- eh_depth
|
||||
- Depth of this extent node in the extent tree. 0 = this extent node
|
||||
points to data blocks; otherwise, this extent node points to other
|
||||
extent nodes. The extent tree can be at most 5 levels deep: a logical
|
||||
block number can be at most ``2^32``, and the smallest ``n`` that
|
||||
satisfies ``4*(((blocksize - 12)/12)^n) >= 2^32`` is 5.
|
||||
* - 0x8
|
||||
- \_\_le32
|
||||
- eh\_generation
|
||||
- __le32
|
||||
- eh_generation
|
||||
- Generation of the tree. (Used by Lustre, but not standard ext4).
|
||||
|
||||
Internal nodes of the extent tree, also known as index nodes, are
|
||||
|
@ -112,22 +112,22 @@ recorded as ``struct ext4_extent_idx``, and are 12 bytes long:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- ei\_block
|
||||
- __le32
|
||||
- ei_block
|
||||
- This index node covers file blocks from 'block' onward.
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- ei\_leaf\_lo
|
||||
- __le32
|
||||
- ei_leaf_lo
|
||||
- Lower 32-bits of the block number of the extent node that is the next
|
||||
level lower in the tree. The tree node pointed to can be either another
|
||||
internal node or a leaf node, described below.
|
||||
* - 0x8
|
||||
- \_\_le16
|
||||
- ei\_leaf\_hi
|
||||
- __le16
|
||||
- ei_leaf_hi
|
||||
- Upper 16-bits of the previous field.
|
||||
* - 0xA
|
||||
- \_\_u16
|
||||
- ei\_unused
|
||||
- __u16
|
||||
- ei_unused
|
||||
-
|
||||
|
||||
Leaf nodes of the extent tree are recorded as ``struct ext4_extent``,
|
||||
|
@ -142,24 +142,24 @@ and are also 12 bytes long:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- ee\_block
|
||||
- __le32
|
||||
- ee_block
|
||||
- First file block number that this extent covers.
|
||||
* - 0x4
|
||||
- \_\_le16
|
||||
- ee\_len
|
||||
- __le16
|
||||
- ee_len
|
||||
- Number of blocks covered by extent. If the value of this field is <=
|
||||
32768, the extent is initialized. If the value of the field is > 32768,
|
||||
the extent is uninitialized and the actual extent length is ``ee_len`` -
|
||||
32768. Therefore, the maximum length of a initialized extent is 32768
|
||||
blocks, and the maximum length of an uninitialized extent is 32767.
|
||||
* - 0x6
|
||||
- \_\_le16
|
||||
- ee\_start\_hi
|
||||
- __le16
|
||||
- ee_start_hi
|
||||
- Upper 16-bits of the block number to which this extent points.
|
||||
* - 0x8
|
||||
- \_\_le32
|
||||
- ee\_start\_lo
|
||||
- __le32
|
||||
- ee_start_lo
|
||||
- Lower 32-bits of the block number to which this extent points.
|
||||
|
||||
Prior to the introduction of metadata checksums, the extent header +
|
||||
|
@ -182,8 +182,8 @@ including) the checksum itself.
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- eb\_checksum
|
||||
- __le32
|
||||
- eb_checksum
|
||||
- Checksum of the extent block, crc32c(uuid+inum+igeneration+extentblock)
|
||||
|
||||
Inline Data
|
||||
|
|
|
@ -11,12 +11,12 @@ file is smaller than 60 bytes, then the data are stored inline in
|
|||
attribute space, then it might be found as an extended attribute
|
||||
“system.data” within the inode body (“ibody EA”). This of course
|
||||
constrains the amount of extended attributes one can attach to an inode.
|
||||
If the data size increases beyond i\_block + ibody EA, a regular block
|
||||
If the data size increases beyond i_block + ibody EA, a regular block
|
||||
is allocated and the contents moved to that block.
|
||||
|
||||
Pending a change to compact the extended attribute key used to store
|
||||
inline data, one ought to be able to store 160 bytes of data in a
|
||||
256-byte inode (as of June 2015, when i\_extra\_isize is 28). Prior to
|
||||
256-byte inode (as of June 2015, when i_extra_isize is 28). Prior to
|
||||
that, the limit was 156 bytes due to inefficient use of inode space.
|
||||
|
||||
The inline data feature requires the presence of an extended attribute
|
||||
|
@ -25,12 +25,12 @@ for “system.data”, even if the attribute value is zero length.
|
|||
Inline Directories
|
||||
~~~~~~~~~~~~~~~~~~
|
||||
|
||||
The first four bytes of i\_block are the inode number of the parent
|
||||
The first four bytes of i_block are the inode number of the parent
|
||||
directory. Following that is a 56-byte space for an array of directory
|
||||
entries; see ``struct ext4_dir_entry``. If there is a “system.data”
|
||||
attribute in the inode body, the EA value is an array of
|
||||
``struct ext4_dir_entry`` as well. Note that for inline directories, the
|
||||
i\_block and EA space are treated as separate dirent blocks; directory
|
||||
i_block and EA space are treated as separate dirent blocks; directory
|
||||
entries cannot span the two.
|
||||
|
||||
Inline directory entries are not checksummed, as the inode checksum
|
||||
|
|
|
@ -38,138 +38,138 @@ The inode table entry is laid out in ``struct ext4_inode``.
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le16
|
||||
- i\_mode
|
||||
- __le16
|
||||
- i_mode
|
||||
- File mode. See the table i_mode_ below.
|
||||
* - 0x2
|
||||
- \_\_le16
|
||||
- i\_uid
|
||||
- __le16
|
||||
- i_uid
|
||||
- Lower 16-bits of Owner UID.
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- i\_size\_lo
|
||||
- __le32
|
||||
- i_size_lo
|
||||
- Lower 32-bits of size in bytes.
|
||||
* - 0x8
|
||||
- \_\_le32
|
||||
- i\_atime
|
||||
- Last access time, in seconds since the epoch. However, if the EA\_INODE
|
||||
- __le32
|
||||
- i_atime
|
||||
- Last access time, in seconds since the epoch. However, if the EA_INODE
|
||||
inode flag is set, this inode stores an extended attribute value and
|
||||
this field contains the checksum of the value.
|
||||
* - 0xC
|
||||
- \_\_le32
|
||||
- i\_ctime
|
||||
- __le32
|
||||
- i_ctime
|
||||
- Last inode change time, in seconds since the epoch. However, if the
|
||||
EA\_INODE inode flag is set, this inode stores an extended attribute
|
||||
EA_INODE inode flag is set, this inode stores an extended attribute
|
||||
value and this field contains the lower 32 bits of the attribute value's
|
||||
reference count.
|
||||
* - 0x10
|
||||
- \_\_le32
|
||||
- i\_mtime
|
||||
- __le32
|
||||
- i_mtime
|
||||
- Last data modification time, in seconds since the epoch. However, if the
|
||||
EA\_INODE inode flag is set, this inode stores an extended attribute
|
||||
EA_INODE inode flag is set, this inode stores an extended attribute
|
||||
value and this field contains the number of the inode that owns the
|
||||
extended attribute.
|
||||
* - 0x14
|
||||
- \_\_le32
|
||||
- i\_dtime
|
||||
- __le32
|
||||
- i_dtime
|
||||
- Deletion Time, in seconds since the epoch.
|
||||
* - 0x18
|
||||
- \_\_le16
|
||||
- i\_gid
|
||||
- __le16
|
||||
- i_gid
|
||||
- Lower 16-bits of GID.
|
||||
* - 0x1A
|
||||
- \_\_le16
|
||||
- i\_links\_count
|
||||
- __le16
|
||||
- i_links_count
|
||||
- Hard link count. Normally, ext4 does not permit an inode to have more
|
||||
than 65,000 hard links. This applies to files as well as directories,
|
||||
which means that there cannot be more than 64,998 subdirectories in a
|
||||
directory (each subdirectory's '..' entry counts as a hard link, as does
|
||||
the '.' entry in the directory itself). With the DIR\_NLINK feature
|
||||
the '.' entry in the directory itself). With the DIR_NLINK feature
|
||||
enabled, ext4 supports more than 64,998 subdirectories by setting this
|
||||
field to 1 to indicate that the number of hard links is not known.
|
||||
* - 0x1C
|
||||
- \_\_le32
|
||||
- i\_blocks\_lo
|
||||
- Lower 32-bits of “block” count. If the huge\_file feature flag is not
|
||||
- __le32
|
||||
- i_blocks_lo
|
||||
- Lower 32-bits of “block” count. If the huge_file feature flag is not
|
||||
set on the filesystem, the file consumes ``i_blocks_lo`` 512-byte blocks
|
||||
on disk. If huge\_file is set and EXT4\_HUGE\_FILE\_FL is NOT set in
|
||||
on disk. If huge_file is set and EXT4_HUGE_FILE_FL is NOT set in
|
||||
``inode.i_flags``, then the file consumes ``i_blocks_lo + (i_blocks_hi
|
||||
<< 32)`` 512-byte blocks on disk. If huge\_file is set and
|
||||
EXT4\_HUGE\_FILE\_FL IS set in ``inode.i_flags``, then this file
|
||||
<< 32)`` 512-byte blocks on disk. If huge_file is set and
|
||||
EXT4_HUGE_FILE_FL IS set in ``inode.i_flags``, then this file
|
||||
consumes (``i_blocks_lo + i_blocks_hi`` << 32) filesystem blocks on
|
||||
disk.
|
||||
* - 0x20
|
||||
- \_\_le32
|
||||
- i\_flags
|
||||
- __le32
|
||||
- i_flags
|
||||
- Inode flags. See the table i_flags_ below.
|
||||
* - 0x24
|
||||
- 4 bytes
|
||||
- i\_osd1
|
||||
- i_osd1
|
||||
- See the table i_osd1_ for more details.
|
||||
* - 0x28
|
||||
- 60 bytes
|
||||
- i\_block[EXT4\_N\_BLOCKS=15]
|
||||
- Block map or extent tree. See the section “The Contents of inode.i\_block”.
|
||||
- i_block[EXT4_N_BLOCKS=15]
|
||||
- Block map or extent tree. See the section “The Contents of inode.i_block”.
|
||||
* - 0x64
|
||||
- \_\_le32
|
||||
- i\_generation
|
||||
- __le32
|
||||
- i_generation
|
||||
- File version (for NFS).
|
||||
* - 0x68
|
||||
- \_\_le32
|
||||
- i\_file\_acl\_lo
|
||||
- __le32
|
||||
- i_file_acl_lo
|
||||
- Lower 32-bits of extended attribute block. ACLs are of course one of
|
||||
many possible extended attributes; I think the name of this field is a
|
||||
result of the first use of extended attributes being for ACLs.
|
||||
* - 0x6C
|
||||
- \_\_le32
|
||||
- i\_size\_high / i\_dir\_acl
|
||||
- __le32
|
||||
- i_size_high / i_dir_acl
|
||||
- Upper 32-bits of file/directory size. In ext2/3 this field was named
|
||||
i\_dir\_acl, though it was usually set to zero and never used.
|
||||
i_dir_acl, though it was usually set to zero and never used.
|
||||
* - 0x70
|
||||
- \_\_le32
|
||||
- i\_obso\_faddr
|
||||
- __le32
|
||||
- i_obso_faddr
|
||||
- (Obsolete) fragment address.
|
||||
* - 0x74
|
||||
- 12 bytes
|
||||
- i\_osd2
|
||||
- i_osd2
|
||||
- See the table i_osd2_ for more details.
|
||||
* - 0x80
|
||||
- \_\_le16
|
||||
- i\_extra\_isize
|
||||
- __le16
|
||||
- i_extra_isize
|
||||
- Size of this inode - 128. Alternately, the size of the extended inode
|
||||
fields beyond the original ext2 inode, including this field.
|
||||
* - 0x82
|
||||
- \_\_le16
|
||||
- i\_checksum\_hi
|
||||
- __le16
|
||||
- i_checksum_hi
|
||||
- Upper 16-bits of the inode checksum.
|
||||
* - 0x84
|
||||
- \_\_le32
|
||||
- i\_ctime\_extra
|
||||
- __le32
|
||||
- i_ctime_extra
|
||||
- Extra change time bits. This provides sub-second precision. See Inode
|
||||
Timestamps section.
|
||||
* - 0x88
|
||||
- \_\_le32
|
||||
- i\_mtime\_extra
|
||||
- __le32
|
||||
- i_mtime_extra
|
||||
- Extra modification time bits. This provides sub-second precision.
|
||||
* - 0x8C
|
||||
- \_\_le32
|
||||
- i\_atime\_extra
|
||||
- __le32
|
||||
- i_atime_extra
|
||||
- Extra access time bits. This provides sub-second precision.
|
||||
* - 0x90
|
||||
- \_\_le32
|
||||
- i\_crtime
|
||||
- __le32
|
||||
- i_crtime
|
||||
- File creation time, in seconds since the epoch.
|
||||
* - 0x94
|
||||
- \_\_le32
|
||||
- i\_crtime\_extra
|
||||
- __le32
|
||||
- i_crtime_extra
|
||||
- Extra file creation time bits. This provides sub-second precision.
|
||||
* - 0x98
|
||||
- \_\_le32
|
||||
- i\_version\_hi
|
||||
- __le32
|
||||
- i_version_hi
|
||||
- Upper 32-bits for version number.
|
||||
* - 0x9C
|
||||
- \_\_le32
|
||||
- i\_projid
|
||||
- __le32
|
||||
- i_projid
|
||||
- Project ID.
|
||||
|
||||
.. _i_mode:
|
||||
|
@ -183,45 +183,45 @@ The ``i_mode`` value is a combination of the following flags:
|
|||
* - Value
|
||||
- Description
|
||||
* - 0x1
|
||||
- S\_IXOTH (Others may execute)
|
||||
- S_IXOTH (Others may execute)
|
||||
* - 0x2
|
||||
- S\_IWOTH (Others may write)
|
||||
- S_IWOTH (Others may write)
|
||||
* - 0x4
|
||||
- S\_IROTH (Others may read)
|
||||
- S_IROTH (Others may read)
|
||||
* - 0x8
|
||||
- S\_IXGRP (Group members may execute)
|
||||
- S_IXGRP (Group members may execute)
|
||||
* - 0x10
|
||||
- S\_IWGRP (Group members may write)
|
||||
- S_IWGRP (Group members may write)
|
||||
* - 0x20
|
||||
- S\_IRGRP (Group members may read)
|
||||
- S_IRGRP (Group members may read)
|
||||
* - 0x40
|
||||
- S\_IXUSR (Owner may execute)
|
||||
- S_IXUSR (Owner may execute)
|
||||
* - 0x80
|
||||
- S\_IWUSR (Owner may write)
|
||||
- S_IWUSR (Owner may write)
|
||||
* - 0x100
|
||||
- S\_IRUSR (Owner may read)
|
||||
- S_IRUSR (Owner may read)
|
||||
* - 0x200
|
||||
- S\_ISVTX (Sticky bit)
|
||||
- S_ISVTX (Sticky bit)
|
||||
* - 0x400
|
||||
- S\_ISGID (Set GID)
|
||||
- S_ISGID (Set GID)
|
||||
* - 0x800
|
||||
- S\_ISUID (Set UID)
|
||||
- S_ISUID (Set UID)
|
||||
* -
|
||||
- These are mutually-exclusive file types:
|
||||
* - 0x1000
|
||||
- S\_IFIFO (FIFO)
|
||||
- S_IFIFO (FIFO)
|
||||
* - 0x2000
|
||||
- S\_IFCHR (Character device)
|
||||
- S_IFCHR (Character device)
|
||||
* - 0x4000
|
||||
- S\_IFDIR (Directory)
|
||||
- S_IFDIR (Directory)
|
||||
* - 0x6000
|
||||
- S\_IFBLK (Block device)
|
||||
- S_IFBLK (Block device)
|
||||
* - 0x8000
|
||||
- S\_IFREG (Regular file)
|
||||
- S_IFREG (Regular file)
|
||||
* - 0xA000
|
||||
- S\_IFLNK (Symbolic link)
|
||||
- S_IFLNK (Symbolic link)
|
||||
* - 0xC000
|
||||
- S\_IFSOCK (Socket)
|
||||
- S_IFSOCK (Socket)
|
||||
|
||||
.. _i_flags:
|
||||
|
||||
|
@ -234,56 +234,56 @@ The ``i_flags`` field is a combination of these values:
|
|||
* - Value
|
||||
- Description
|
||||
* - 0x1
|
||||
- This file requires secure deletion (EXT4\_SECRM\_FL). (not implemented)
|
||||
- This file requires secure deletion (EXT4_SECRM_FL). (not implemented)
|
||||
* - 0x2
|
||||
- This file should be preserved, should undeletion be desired
|
||||
(EXT4\_UNRM\_FL). (not implemented)
|
||||
(EXT4_UNRM_FL). (not implemented)
|
||||
* - 0x4
|
||||
- File is compressed (EXT4\_COMPR\_FL). (not really implemented)
|
||||
- File is compressed (EXT4_COMPR_FL). (not really implemented)
|
||||
* - 0x8
|
||||
- All writes to the file must be synchronous (EXT4\_SYNC\_FL).
|
||||
- All writes to the file must be synchronous (EXT4_SYNC_FL).
|
||||
* - 0x10
|
||||
- File is immutable (EXT4\_IMMUTABLE\_FL).
|
||||
- File is immutable (EXT4_IMMUTABLE_FL).
|
||||
* - 0x20
|
||||
- File can only be appended (EXT4\_APPEND\_FL).
|
||||
- File can only be appended (EXT4_APPEND_FL).
|
||||
* - 0x40
|
||||
- The dump(1) utility should not dump this file (EXT4\_NODUMP\_FL).
|
||||
- The dump(1) utility should not dump this file (EXT4_NODUMP_FL).
|
||||
* - 0x80
|
||||
- Do not update access time (EXT4\_NOATIME\_FL).
|
||||
- Do not update access time (EXT4_NOATIME_FL).
|
||||
* - 0x100
|
||||
- Dirty compressed file (EXT4\_DIRTY\_FL). (not used)
|
||||
- Dirty compressed file (EXT4_DIRTY_FL). (not used)
|
||||
* - 0x200
|
||||
- File has one or more compressed clusters (EXT4\_COMPRBLK\_FL). (not used)
|
||||
- File has one or more compressed clusters (EXT4_COMPRBLK_FL). (not used)
|
||||
* - 0x400
|
||||
- Do not compress file (EXT4\_NOCOMPR\_FL). (not used)
|
||||
- Do not compress file (EXT4_NOCOMPR_FL). (not used)
|
||||
* - 0x800
|
||||
- Encrypted inode (EXT4\_ENCRYPT\_FL). This bit value previously was
|
||||
EXT4\_ECOMPR\_FL (compression error), which was never used.
|
||||
- Encrypted inode (EXT4_ENCRYPT_FL). This bit value previously was
|
||||
EXT4_ECOMPR_FL (compression error), which was never used.
|
||||
* - 0x1000
|
||||
- Directory has hashed indexes (EXT4\_INDEX\_FL).
|
||||
- Directory has hashed indexes (EXT4_INDEX_FL).
|
||||
* - 0x2000
|
||||
- AFS magic directory (EXT4\_IMAGIC\_FL).
|
||||
- AFS magic directory (EXT4_IMAGIC_FL).
|
||||
* - 0x4000
|
||||
- File data must always be written through the journal
|
||||
(EXT4\_JOURNAL\_DATA\_FL).
|
||||
(EXT4_JOURNAL_DATA_FL).
|
||||
* - 0x8000
|
||||
- File tail should not be merged (EXT4\_NOTAIL\_FL). (not used by ext4)
|
||||
- File tail should not be merged (EXT4_NOTAIL_FL). (not used by ext4)
|
||||
* - 0x10000
|
||||
- All directory entry data should be written synchronously (see
|
||||
``dirsync``) (EXT4\_DIRSYNC\_FL).
|
||||
``dirsync``) (EXT4_DIRSYNC_FL).
|
||||
* - 0x20000
|
||||
- Top of directory hierarchy (EXT4\_TOPDIR\_FL).
|
||||
- Top of directory hierarchy (EXT4_TOPDIR_FL).
|
||||
* - 0x40000
|
||||
- This is a huge file (EXT4\_HUGE\_FILE\_FL).
|
||||
- This is a huge file (EXT4_HUGE_FILE_FL).
|
||||
* - 0x80000
|
||||
- Inode uses extents (EXT4\_EXTENTS\_FL).
|
||||
- Inode uses extents (EXT4_EXTENTS_FL).
|
||||
* - 0x100000
|
||||
- Verity protected file (EXT4\_VERITY\_FL).
|
||||
- Verity protected file (EXT4_VERITY_FL).
|
||||
* - 0x200000
|
||||
- Inode stores a large extended attribute value in its data blocks
|
||||
(EXT4\_EA\_INODE\_FL).
|
||||
(EXT4_EA_INODE_FL).
|
||||
* - 0x400000
|
||||
- This file has blocks allocated past EOF (EXT4\_EOFBLOCKS\_FL).
|
||||
- This file has blocks allocated past EOF (EXT4_EOFBLOCKS_FL).
|
||||
(deprecated)
|
||||
* - 0x01000000
|
||||
- Inode is a snapshot (``EXT4_SNAPFILE_FL``). (not in mainline)
|
||||
|
@ -294,21 +294,21 @@ The ``i_flags`` field is a combination of these values:
|
|||
- Snapshot shrink has completed (``EXT4_SNAPFILE_SHRUNK_FL``). (not in
|
||||
mainline)
|
||||
* - 0x10000000
|
||||
- Inode has inline data (EXT4\_INLINE\_DATA\_FL).
|
||||
- Inode has inline data (EXT4_INLINE_DATA_FL).
|
||||
* - 0x20000000
|
||||
- Create children with the same project ID (EXT4\_PROJINHERIT\_FL).
|
||||
- Create children with the same project ID (EXT4_PROJINHERIT_FL).
|
||||
* - 0x80000000
|
||||
- Reserved for ext4 library (EXT4\_RESERVED\_FL).
|
||||
- Reserved for ext4 library (EXT4_RESERVED_FL).
|
||||
* -
|
||||
- Aggregate flags:
|
||||
* - 0x705BDFFF
|
||||
- User-visible flags.
|
||||
* - 0x604BC0FF
|
||||
- User-modifiable flags. Note that while EXT4\_JOURNAL\_DATA\_FL and
|
||||
EXT4\_EXTENTS\_FL can be set with setattr, they are not in the kernel's
|
||||
EXT4\_FL\_USER\_MODIFIABLE mask, since it needs to handle the setting of
|
||||
- User-modifiable flags. Note that while EXT4_JOURNAL_DATA_FL and
|
||||
EXT4_EXTENTS_FL can be set with setattr, they are not in the kernel's
|
||||
EXT4_FL_USER_MODIFIABLE mask, since it needs to handle the setting of
|
||||
these flags in a special manner and they are masked out of the set of
|
||||
flags that are saved directly to i\_flags.
|
||||
flags that are saved directly to i_flags.
|
||||
|
||||
.. _i_osd1:
|
||||
|
||||
|
@ -325,9 +325,9 @@ Linux:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- l\_i\_version
|
||||
- Inode version. However, if the EA\_INODE inode flag is set, this inode
|
||||
- __le32
|
||||
- l_i_version
|
||||
- Inode version. However, if the EA_INODE inode flag is set, this inode
|
||||
stores an extended attribute value and this field contains the upper 32
|
||||
bits of the attribute value's reference count.
|
||||
|
||||
|
@ -342,8 +342,8 @@ Hurd:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- h\_i\_translator
|
||||
- __le32
|
||||
- h_i_translator
|
||||
- ??
|
||||
|
||||
Masix:
|
||||
|
@ -357,8 +357,8 @@ Masix:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- m\_i\_reserved
|
||||
- __le32
|
||||
- m_i_reserved
|
||||
- ??
|
||||
|
||||
.. _i_osd2:
|
||||
|
@ -376,30 +376,30 @@ Linux:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le16
|
||||
- l\_i\_blocks\_high
|
||||
- __le16
|
||||
- l_i_blocks_high
|
||||
- Upper 16-bits of the block count. Please see the note attached to
|
||||
i\_blocks\_lo.
|
||||
i_blocks_lo.
|
||||
* - 0x2
|
||||
- \_\_le16
|
||||
- l\_i\_file\_acl\_high
|
||||
- __le16
|
||||
- l_i_file_acl_high
|
||||
- Upper 16-bits of the extended attribute block (historically, the file
|
||||
ACL location). See the Extended Attributes section below.
|
||||
* - 0x4
|
||||
- \_\_le16
|
||||
- l\_i\_uid\_high
|
||||
- __le16
|
||||
- l_i_uid_high
|
||||
- Upper 16-bits of the Owner UID.
|
||||
* - 0x6
|
||||
- \_\_le16
|
||||
- l\_i\_gid\_high
|
||||
- __le16
|
||||
- l_i_gid_high
|
||||
- Upper 16-bits of the GID.
|
||||
* - 0x8
|
||||
- \_\_le16
|
||||
- l\_i\_checksum\_lo
|
||||
- __le16
|
||||
- l_i_checksum_lo
|
||||
- Lower 16-bits of the inode checksum.
|
||||
* - 0xA
|
||||
- \_\_le16
|
||||
- l\_i\_reserved
|
||||
- __le16
|
||||
- l_i_reserved
|
||||
- Unused.
|
||||
|
||||
Hurd:
|
||||
|
@ -413,24 +413,24 @@ Hurd:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le16
|
||||
- h\_i\_reserved1
|
||||
- __le16
|
||||
- h_i_reserved1
|
||||
- ??
|
||||
* - 0x2
|
||||
- \_\_u16
|
||||
- h\_i\_mode\_high
|
||||
- __u16
|
||||
- h_i_mode_high
|
||||
- Upper 16-bits of the file mode.
|
||||
* - 0x4
|
||||
- \_\_le16
|
||||
- h\_i\_uid\_high
|
||||
- __le16
|
||||
- h_i_uid_high
|
||||
- Upper 16-bits of the Owner UID.
|
||||
* - 0x6
|
||||
- \_\_le16
|
||||
- h\_i\_gid\_high
|
||||
- __le16
|
||||
- h_i_gid_high
|
||||
- Upper 16-bits of the GID.
|
||||
* - 0x8
|
||||
- \_\_u32
|
||||
- h\_i\_author
|
||||
- __u32
|
||||
- h_i_author
|
||||
- Author code?
|
||||
|
||||
Masix:
|
||||
|
@ -444,17 +444,17 @@ Masix:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le16
|
||||
- h\_i\_reserved1
|
||||
- __le16
|
||||
- h_i_reserved1
|
||||
- ??
|
||||
* - 0x2
|
||||
- \_\_u16
|
||||
- m\_i\_file\_acl\_high
|
||||
- __u16
|
||||
- m_i_file_acl_high
|
||||
- Upper 16-bits of the extended attribute block (historically, the file
|
||||
ACL location).
|
||||
* - 0x4
|
||||
- \_\_u32
|
||||
- m\_i\_reserved2[2]
|
||||
- __u32
|
||||
- m_i_reserved2[2]
|
||||
- ??
|
||||
|
||||
Inode Size
|
||||
|
@ -466,11 +466,11 @@ In ext2 and ext3, the inode structure size was fixed at 128 bytes
|
|||
on-disk inode at format time for all inodes in the filesystem to provide
|
||||
space beyond the end of the original ext2 inode. The on-disk inode
|
||||
record size is recorded in the superblock as ``s_inode_size``. The
|
||||
number of bytes actually used by struct ext4\_inode beyond the original
|
||||
number of bytes actually used by struct ext4_inode beyond the original
|
||||
128-byte ext2 inode is recorded in the ``i_extra_isize`` field for each
|
||||
inode, which allows struct ext4\_inode to grow for a new kernel without
|
||||
inode, which allows struct ext4_inode to grow for a new kernel without
|
||||
having to upgrade all of the on-disk inodes. Access to fields beyond
|
||||
EXT2\_GOOD\_OLD\_INODE\_SIZE should be verified to be within
|
||||
EXT2_GOOD_OLD_INODE_SIZE should be verified to be within
|
||||
``i_extra_isize``. By default, ext4 inode records are 256 bytes, and (as
|
||||
of August 2019) the inode structure is 160 bytes
|
||||
(``i_extra_isize = 32``). The extra space between the end of the inode
|
||||
|
@ -516,7 +516,7 @@ creation time (crtime); this field is 64-bits wide and decoded in the
|
|||
same manner as 64-bit [cma]time. Neither crtime nor dtime are accessible
|
||||
through the regular stat() interface, though debugfs will report them.
|
||||
|
||||
We use the 32-bit signed time value plus (2^32 \* (extra epoch bits)).
|
||||
We use the 32-bit signed time value plus (2^32 * (extra epoch bits)).
|
||||
In other words:
|
||||
|
||||
.. list-table::
|
||||
|
@ -525,8 +525,8 @@ In other words:
|
|||
|
||||
* - Extra epoch bits
|
||||
- MSB of 32-bit time
|
||||
- Adjustment for signed 32-bit to 64-bit tv\_sec
|
||||
- Decoded 64-bit tv\_sec
|
||||
- Adjustment for signed 32-bit to 64-bit tv_sec
|
||||
- Decoded 64-bit tv_sec
|
||||
- valid time range
|
||||
* - 0 0
|
||||
- 1
|
||||
|
|
|
@ -63,8 +63,8 @@ Generally speaking, the journal has this format:
|
|||
:header-rows: 1
|
||||
|
||||
* - Superblock
|
||||
- descriptor\_block (data\_blocks or revocation\_block) [more data or
|
||||
revocations] commmit\_block
|
||||
- descriptor_block (data_blocks or revocation_block) [more data or
|
||||
revocations] commmit_block
|
||||
- [more transactions...]
|
||||
* -
|
||||
- One transaction
|
||||
|
@ -93,8 +93,8 @@ superblock.
|
|||
* - 1024 bytes of padding
|
||||
- ext4 Superblock
|
||||
- Journal Superblock
|
||||
- descriptor\_block (data\_blocks or revocation\_block) [more data or
|
||||
revocations] commmit\_block
|
||||
- descriptor_block (data_blocks or revocation_block) [more data or
|
||||
revocations] commmit_block
|
||||
- [more transactions...]
|
||||
* -
|
||||
-
|
||||
|
@ -117,17 +117,17 @@ Every block in the journal starts with a common 12-byte header
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_be32
|
||||
- h\_magic
|
||||
- __be32
|
||||
- h_magic
|
||||
- jbd2 magic number, 0xC03B3998.
|
||||
* - 0x4
|
||||
- \_\_be32
|
||||
- h\_blocktype
|
||||
- __be32
|
||||
- h_blocktype
|
||||
- Description of what this block contains. See the jbd2_blocktype_ table
|
||||
below.
|
||||
* - 0x8
|
||||
- \_\_be32
|
||||
- h\_sequence
|
||||
- __be32
|
||||
- h_sequence
|
||||
- The transaction ID that goes with this block.
|
||||
|
||||
.. _jbd2_blocktype:
|
||||
|
@ -177,99 +177,99 @@ which is 1024 bytes long:
|
|||
-
|
||||
- Static information describing the journal.
|
||||
* - 0x0
|
||||
- journal\_header\_t (12 bytes)
|
||||
- s\_header
|
||||
- journal_header_t (12 bytes)
|
||||
- s_header
|
||||
- Common header identifying this as a superblock.
|
||||
* - 0xC
|
||||
- \_\_be32
|
||||
- s\_blocksize
|
||||
- __be32
|
||||
- s_blocksize
|
||||
- Journal device block size.
|
||||
* - 0x10
|
||||
- \_\_be32
|
||||
- s\_maxlen
|
||||
- __be32
|
||||
- s_maxlen
|
||||
- Total number of blocks in this journal.
|
||||
* - 0x14
|
||||
- \_\_be32
|
||||
- s\_first
|
||||
- __be32
|
||||
- s_first
|
||||
- First block of log information.
|
||||
* -
|
||||
-
|
||||
-
|
||||
- Dynamic information describing the current state of the log.
|
||||
* - 0x18
|
||||
- \_\_be32
|
||||
- s\_sequence
|
||||
- __be32
|
||||
- s_sequence
|
||||
- First commit ID expected in log.
|
||||
* - 0x1C
|
||||
- \_\_be32
|
||||
- s\_start
|
||||
- __be32
|
||||
- s_start
|
||||
- Block number of the start of log. Contrary to the comments, this field
|
||||
being zero does not imply that the journal is clean!
|
||||
* - 0x20
|
||||
- \_\_be32
|
||||
- s\_errno
|
||||
- Error value, as set by jbd2\_journal\_abort().
|
||||
- __be32
|
||||
- s_errno
|
||||
- Error value, as set by jbd2_journal_abort().
|
||||
* -
|
||||
-
|
||||
-
|
||||
- The remaining fields are only valid in a v2 superblock.
|
||||
* - 0x24
|
||||
- \_\_be32
|
||||
- s\_feature\_compat;
|
||||
- __be32
|
||||
- s_feature_compat;
|
||||
- Compatible feature set. See the table jbd2_compat_ below.
|
||||
* - 0x28
|
||||
- \_\_be32
|
||||
- s\_feature\_incompat
|
||||
- __be32
|
||||
- s_feature_incompat
|
||||
- Incompatible feature set. See the table jbd2_incompat_ below.
|
||||
* - 0x2C
|
||||
- \_\_be32
|
||||
- s\_feature\_ro\_compat
|
||||
- __be32
|
||||
- s_feature_ro_compat
|
||||
- Read-only compatible feature set. There aren't any of these currently.
|
||||
* - 0x30
|
||||
- \_\_u8
|
||||
- s\_uuid[16]
|
||||
- __u8
|
||||
- s_uuid[16]
|
||||
- 128-bit uuid for journal. This is compared against the copy in the ext4
|
||||
super block at mount time.
|
||||
* - 0x40
|
||||
- \_\_be32
|
||||
- s\_nr\_users
|
||||
- __be32
|
||||
- s_nr_users
|
||||
- Number of file systems sharing this journal.
|
||||
* - 0x44
|
||||
- \_\_be32
|
||||
- s\_dynsuper
|
||||
- __be32
|
||||
- s_dynsuper
|
||||
- Location of dynamic super block copy. (Not used?)
|
||||
* - 0x48
|
||||
- \_\_be32
|
||||
- s\_max\_transaction
|
||||
- __be32
|
||||
- s_max_transaction
|
||||
- Limit of journal blocks per transaction. (Not used?)
|
||||
* - 0x4C
|
||||
- \_\_be32
|
||||
- s\_max\_trans\_data
|
||||
- __be32
|
||||
- s_max_trans_data
|
||||
- Limit of data blocks per transaction. (Not used?)
|
||||
* - 0x50
|
||||
- \_\_u8
|
||||
- s\_checksum\_type
|
||||
- __u8
|
||||
- s_checksum_type
|
||||
- Checksum algorithm used for the journal. See jbd2_checksum_type_ for
|
||||
more info.
|
||||
* - 0x51
|
||||
- \_\_u8[3]
|
||||
- s\_padding2
|
||||
- __u8[3]
|
||||
- s_padding2
|
||||
-
|
||||
* - 0x54
|
||||
- \_\_be32
|
||||
- s\_num\_fc\_blocks
|
||||
- __be32
|
||||
- s_num_fc_blocks
|
||||
- Number of fast commit blocks in the journal.
|
||||
* - 0x58
|
||||
- \_\_u32
|
||||
- s\_padding[42]
|
||||
- __u32
|
||||
- s_padding[42]
|
||||
-
|
||||
* - 0xFC
|
||||
- \_\_be32
|
||||
- s\_checksum
|
||||
- __be32
|
||||
- s_checksum
|
||||
- Checksum of the entire superblock, with this field set to zero.
|
||||
* - 0x100
|
||||
- \_\_u8
|
||||
- s\_users[16\*48]
|
||||
- __u8
|
||||
- s_users[16*48]
|
||||
- ids of all file systems sharing the log. e2fsprogs/Linux don't allow
|
||||
shared external journals, but I imagine Lustre (or ocfs2?), which use
|
||||
the jbd2 code, might.
|
||||
|
@ -286,7 +286,7 @@ The journal compat features are any combination of the following:
|
|||
- Description
|
||||
* - 0x1
|
||||
- Journal maintains checksums on the data blocks.
|
||||
(JBD2\_FEATURE\_COMPAT\_CHECKSUM)
|
||||
(JBD2_FEATURE_COMPAT_CHECKSUM)
|
||||
|
||||
.. _jbd2_incompat:
|
||||
|
||||
|
@ -299,23 +299,23 @@ The journal incompat features are any combination of the following:
|
|||
* - Value
|
||||
- Description
|
||||
* - 0x1
|
||||
- Journal has block revocation records. (JBD2\_FEATURE\_INCOMPAT\_REVOKE)
|
||||
- Journal has block revocation records. (JBD2_FEATURE_INCOMPAT_REVOKE)
|
||||
* - 0x2
|
||||
- Journal can deal with 64-bit block numbers.
|
||||
(JBD2\_FEATURE\_INCOMPAT\_64BIT)
|
||||
(JBD2_FEATURE_INCOMPAT_64BIT)
|
||||
* - 0x4
|
||||
- Journal commits asynchronously. (JBD2\_FEATURE\_INCOMPAT\_ASYNC\_COMMIT)
|
||||
- Journal commits asynchronously. (JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)
|
||||
* - 0x8
|
||||
- This journal uses v2 of the checksum on-disk format. Each journal
|
||||
metadata block gets its own checksum, and the block tags in the
|
||||
descriptor table contain checksums for each of the data blocks in the
|
||||
journal. (JBD2\_FEATURE\_INCOMPAT\_CSUM\_V2)
|
||||
journal. (JBD2_FEATURE_INCOMPAT_CSUM_V2)
|
||||
* - 0x10
|
||||
- This journal uses v3 of the checksum on-disk format. This is the same as
|
||||
v2, but the journal block tag size is fixed regardless of the size of
|
||||
block numbers. (JBD2\_FEATURE\_INCOMPAT\_CSUM\_V3)
|
||||
block numbers. (JBD2_FEATURE_INCOMPAT_CSUM_V3)
|
||||
* - 0x20
|
||||
- Journal has fast commit blocks. (JBD2\_FEATURE\_INCOMPAT\_FAST\_COMMIT)
|
||||
- Journal has fast commit blocks. (JBD2_FEATURE_INCOMPAT_FAST_COMMIT)
|
||||
|
||||
.. _jbd2_checksum_type:
|
||||
|
||||
|
@ -355,11 +355,11 @@ Descriptor blocks consume at least 36 bytes, but use a full block:
|
|||
- Name
|
||||
- Descriptor
|
||||
* - 0x0
|
||||
- journal\_header\_t
|
||||
- journal_header_t
|
||||
- (open coded)
|
||||
- Common block header.
|
||||
* - 0xC
|
||||
- struct journal\_block\_tag\_s
|
||||
- struct journal_block_tag_s
|
||||
- open coded array[]
|
||||
- Enough tags either to fill up the block or to describe all the data
|
||||
blocks that follow this descriptor block.
|
||||
|
@ -367,7 +367,7 @@ Descriptor blocks consume at least 36 bytes, but use a full block:
|
|||
Journal block tags have any of the following formats, depending on which
|
||||
journal feature and block tag flags are set.
|
||||
|
||||
If JBD2\_FEATURE\_INCOMPAT\_CSUM\_V3 is set, the journal block tag is
|
||||
If JBD2_FEATURE_INCOMPAT_CSUM_V3 is set, the journal block tag is
|
||||
defined as ``struct journal_block_tag3_s``, which looks like the
|
||||
following. The size is 16 or 32 bytes.
|
||||
|
||||
|
@ -380,24 +380,24 @@ following. The size is 16 or 32 bytes.
|
|||
- Name
|
||||
- Descriptor
|
||||
* - 0x0
|
||||
- \_\_be32
|
||||
- t\_blocknr
|
||||
- __be32
|
||||
- t_blocknr
|
||||
- Lower 32-bits of the location of where the corresponding data block
|
||||
should end up on disk.
|
||||
* - 0x4
|
||||
- \_\_be32
|
||||
- t\_flags
|
||||
- __be32
|
||||
- t_flags
|
||||
- Flags that go with the descriptor. See the table jbd2_tag_flags_ for
|
||||
more info.
|
||||
* - 0x8
|
||||
- \_\_be32
|
||||
- t\_blocknr\_high
|
||||
- __be32
|
||||
- t_blocknr_high
|
||||
- Upper 32-bits of the location of where the corresponding data block
|
||||
should end up on disk. This is zero if JBD2\_FEATURE\_INCOMPAT\_64BIT is
|
||||
should end up on disk. This is zero if JBD2_FEATURE_INCOMPAT_64BIT is
|
||||
not enabled.
|
||||
* - 0xC
|
||||
- \_\_be32
|
||||
- t\_checksum
|
||||
- __be32
|
||||
- t_checksum
|
||||
- Checksum of the journal UUID, the sequence number, and the data block.
|
||||
* -
|
||||
-
|
||||
|
@ -433,7 +433,7 @@ The journal tag flags are any combination of the following:
|
|||
* - 0x8
|
||||
- This is the last tag in this descriptor block.
|
||||
|
||||
If JBD2\_FEATURE\_INCOMPAT\_CSUM\_V3 is NOT set, the journal block tag
|
||||
If JBD2_FEATURE_INCOMPAT_CSUM_V3 is NOT set, the journal block tag
|
||||
is defined as ``struct journal_block_tag_s``, which looks like the
|
||||
following. The size is 8, 12, 24, or 28 bytes:
|
||||
|
||||
|
@ -446,18 +446,18 @@ following. The size is 8, 12, 24, or 28 bytes:
|
|||
- Name
|
||||
- Descriptor
|
||||
* - 0x0
|
||||
- \_\_be32
|
||||
- t\_blocknr
|
||||
- __be32
|
||||
- t_blocknr
|
||||
- Lower 32-bits of the location of where the corresponding data block
|
||||
should end up on disk.
|
||||
* - 0x4
|
||||
- \_\_be16
|
||||
- t\_checksum
|
||||
- __be16
|
||||
- t_checksum
|
||||
- Checksum of the journal UUID, the sequence number, and the data block.
|
||||
Note that only the lower 16 bits are stored.
|
||||
* - 0x6
|
||||
- \_\_be16
|
||||
- t\_flags
|
||||
- __be16
|
||||
- t_flags
|
||||
- Flags that go with the descriptor. See the table jbd2_tag_flags_ for
|
||||
more info.
|
||||
* -
|
||||
|
@ -466,8 +466,8 @@ following. The size is 8, 12, 24, or 28 bytes:
|
|||
- This next field is only present if the super block indicates support for
|
||||
64-bit block numbers.
|
||||
* - 0x8
|
||||
- \_\_be32
|
||||
- t\_blocknr\_high
|
||||
- __be32
|
||||
- t_blocknr_high
|
||||
- Upper 32-bits of the location of where the corresponding data block
|
||||
should end up on disk.
|
||||
* -
|
||||
|
@ -483,8 +483,8 @@ following. The size is 8, 12, 24, or 28 bytes:
|
|||
``j_uuid`` field in ``struct journal_s``, but only tune2fs touches that
|
||||
field.
|
||||
|
||||
If JBD2\_FEATURE\_INCOMPAT\_CSUM\_V2 or
|
||||
JBD2\_FEATURE\_INCOMPAT\_CSUM\_V3 are set, the end of the block is a
|
||||
If JBD2_FEATURE_INCOMPAT_CSUM_V2 or
|
||||
JBD2_FEATURE_INCOMPAT_CSUM_V3 are set, the end of the block is a
|
||||
``struct jbd2_journal_block_tail``, which looks like this:
|
||||
|
||||
.. list-table::
|
||||
|
@ -496,8 +496,8 @@ JBD2\_FEATURE\_INCOMPAT\_CSUM\_V3 are set, the end of the block is a
|
|||
- Name
|
||||
- Descriptor
|
||||
* - 0x0
|
||||
- \_\_be32
|
||||
- t\_checksum
|
||||
- __be32
|
||||
- t_checksum
|
||||
- Checksum of the journal UUID + the descriptor block, with this field set
|
||||
to zero.
|
||||
|
||||
|
@ -538,25 +538,25 @@ length, but use a full block:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- journal\_header\_t
|
||||
- r\_header
|
||||
- journal_header_t
|
||||
- r_header
|
||||
- Common block header.
|
||||
* - 0xC
|
||||
- \_\_be32
|
||||
- r\_count
|
||||
- __be32
|
||||
- r_count
|
||||
- Number of bytes used in this block.
|
||||
* - 0x10
|
||||
- \_\_be32 or \_\_be64
|
||||
- __be32 or __be64
|
||||
- blocks[0]
|
||||
- Blocks to revoke.
|
||||
|
||||
After r\_count is a linear array of block numbers that are effectively
|
||||
After r_count is a linear array of block numbers that are effectively
|
||||
revoked by this transaction. The size of each block number is 8 bytes if
|
||||
the superblock advertises 64-bit block number support, or 4 bytes
|
||||
otherwise.
|
||||
|
||||
If JBD2\_FEATURE\_INCOMPAT\_CSUM\_V2 or
|
||||
JBD2\_FEATURE\_INCOMPAT\_CSUM\_V3 are set, the end of the revocation
|
||||
If JBD2_FEATURE_INCOMPAT_CSUM_V2 or
|
||||
JBD2_FEATURE_INCOMPAT_CSUM_V3 are set, the end of the revocation
|
||||
block is a ``struct jbd2_journal_revoke_tail``, which has this format:
|
||||
|
||||
.. list-table::
|
||||
|
@ -568,8 +568,8 @@ block is a ``struct jbd2_journal_revoke_tail``, which has this format:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_be32
|
||||
- r\_checksum
|
||||
- __be32
|
||||
- r_checksum
|
||||
- Checksum of the journal UUID + revocation block
|
||||
|
||||
Commit Block
|
||||
|
@ -592,38 +592,38 @@ bytes long (but uses a full block):
|
|||
- Name
|
||||
- Descriptor
|
||||
* - 0x0
|
||||
- journal\_header\_s
|
||||
- journal_header_s
|
||||
- (open coded)
|
||||
- Common block header.
|
||||
* - 0xC
|
||||
- unsigned char
|
||||
- h\_chksum\_type
|
||||
- h_chksum_type
|
||||
- The type of checksum to use to verify the integrity of the data blocks
|
||||
in the transaction. See jbd2_checksum_type_ for more info.
|
||||
* - 0xD
|
||||
- unsigned char
|
||||
- h\_chksum\_size
|
||||
- h_chksum_size
|
||||
- The number of bytes used by the checksum. Most likely 4.
|
||||
* - 0xE
|
||||
- unsigned char
|
||||
- h\_padding[2]
|
||||
- h_padding[2]
|
||||
-
|
||||
* - 0x10
|
||||
- \_\_be32
|
||||
- h\_chksum[JBD2\_CHECKSUM\_BYTES]
|
||||
- __be32
|
||||
- h_chksum[JBD2_CHECKSUM_BYTES]
|
||||
- 32 bytes of space to store checksums. If
|
||||
JBD2\_FEATURE\_INCOMPAT\_CSUM\_V2 or JBD2\_FEATURE\_INCOMPAT\_CSUM\_V3
|
||||
JBD2_FEATURE_INCOMPAT_CSUM_V2 or JBD2_FEATURE_INCOMPAT_CSUM_V3
|
||||
are set, the first ``__be32`` is the checksum of the journal UUID and
|
||||
the entire commit block, with this field zeroed. If
|
||||
JBD2\_FEATURE\_COMPAT\_CHECKSUM is set, the first ``__be32`` is the
|
||||
JBD2_FEATURE_COMPAT_CHECKSUM is set, the first ``__be32`` is the
|
||||
crc32 of all the blocks already written to the transaction.
|
||||
* - 0x30
|
||||
- \_\_be64
|
||||
- h\_commit\_sec
|
||||
- __be64
|
||||
- h_commit_sec
|
||||
- The time that the transaction was committed, in seconds since the epoch.
|
||||
* - 0x38
|
||||
- \_\_be32
|
||||
- h\_commit\_nsec
|
||||
- __be32
|
||||
- h_commit_nsec
|
||||
- Nanoseconds component of the above timestamp.
|
||||
|
||||
Fast commits
|
||||
|
|
|
@ -7,8 +7,8 @@ Multiple mount protection (MMP) is a feature that protects the
|
|||
filesystem against multiple hosts trying to use the filesystem
|
||||
simultaneously. When a filesystem is opened (for mounting, or fsck,
|
||||
etc.), the MMP code running on the node (call it node A) checks a
|
||||
sequence number. If the sequence number is EXT4\_MMP\_SEQ\_CLEAN, the
|
||||
open continues. If the sequence number is EXT4\_MMP\_SEQ\_FSCK, then
|
||||
sequence number. If the sequence number is EXT4_MMP_SEQ_CLEAN, the
|
||||
open continues. If the sequence number is EXT4_MMP_SEQ_FSCK, then
|
||||
fsck is (hopefully) running, and open fails immediately. Otherwise, the
|
||||
open code will wait for twice the specified MMP check interval and check
|
||||
the sequence number again. If the sequence number has changed, then the
|
||||
|
@ -40,38 +40,38 @@ The MMP structure (``struct mmp_struct``) is as follows:
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- mmp\_magic
|
||||
- __le32
|
||||
- mmp_magic
|
||||
- Magic number for MMP, 0x004D4D50 (“MMP”).
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- mmp\_seq
|
||||
- __le32
|
||||
- mmp_seq
|
||||
- Sequence number, updated periodically.
|
||||
* - 0x8
|
||||
- \_\_le64
|
||||
- mmp\_time
|
||||
- __le64
|
||||
- mmp_time
|
||||
- Time that the MMP block was last updated.
|
||||
* - 0x10
|
||||
- char[64]
|
||||
- mmp\_nodename
|
||||
- mmp_nodename
|
||||
- Hostname of the node that opened the filesystem.
|
||||
* - 0x50
|
||||
- char[32]
|
||||
- mmp\_bdevname
|
||||
- mmp_bdevname
|
||||
- Block device name of the filesystem.
|
||||
* - 0x70
|
||||
- \_\_le16
|
||||
- mmp\_check\_interval
|
||||
- __le16
|
||||
- mmp_check_interval
|
||||
- The MMP re-check interval, in seconds.
|
||||
* - 0x72
|
||||
- \_\_le16
|
||||
- mmp\_pad1
|
||||
- __le16
|
||||
- mmp_pad1
|
||||
- Zero.
|
||||
* - 0x74
|
||||
- \_\_le32[226]
|
||||
- mmp\_pad2
|
||||
- __le32[226]
|
||||
- mmp_pad2
|
||||
- Zero.
|
||||
* - 0x3FC
|
||||
- \_\_le32
|
||||
- mmp\_checksum
|
||||
- __le32
|
||||
- mmp_checksum
|
||||
- Checksum of the MMP block.
|
||||
|
|
|
@ -7,7 +7,7 @@ An ext4 file system is split into a series of block groups. To reduce
|
|||
performance difficulties due to fragmentation, the block allocator tries
|
||||
very hard to keep each file's blocks within the same group, thereby
|
||||
reducing seek times. The size of a block group is specified in
|
||||
``sb.s_blocks_per_group`` blocks, though it can also calculated as 8 \*
|
||||
``sb.s_blocks_per_group`` blocks, though it can also calculated as 8 *
|
||||
``block_size_in_bytes``. With the default block size of 4KiB, each group
|
||||
will contain 32,768 blocks, for a length of 128MiB. The number of block
|
||||
groups is the size of the device divided by the size of a block group.
|
||||
|
|
|
@ -34,7 +34,7 @@ ext4 reserves some inode for special features, as follows:
|
|||
* - 10
|
||||
- Replica inode, used for some non-upstream feature?
|
||||
* - 11
|
||||
- Traditional first non-reserved inode. Usually this is the lost+found directory. See s\_first\_ino in the superblock.
|
||||
- Traditional first non-reserved inode. Usually this is the lost+found directory. See s_first_ino in the superblock.
|
||||
|
||||
Note that there are also some inodes allocated from non-reserved inode numbers
|
||||
for other filesystem features which are not referenced from standard directory
|
||||
|
@ -47,9 +47,9 @@ hierarchy. These are generally reference from the superblock. They are:
|
|||
* - Superblock field
|
||||
- Description
|
||||
|
||||
* - s\_lpf\_ino
|
||||
* - s_lpf_ino
|
||||
- Inode number of lost+found directory.
|
||||
* - s\_prj\_quota\_inum
|
||||
* - s_prj_quota_inum
|
||||
- Inode number of quota file tracking project quotas
|
||||
* - s\_orphan\_file\_inum
|
||||
* - s_orphan_file_inum
|
||||
- Inode number of file tracking orphan inodes.
|
||||
|
|
|
@ -7,7 +7,7 @@ The superblock records various information about the enclosing
|
|||
filesystem, such as block counts, inode counts, supported features,
|
||||
maintenance information, and more.
|
||||
|
||||
If the sparse\_super feature flag is set, redundant copies of the
|
||||
If the sparse_super feature flag is set, redundant copies of the
|
||||
superblock and group descriptors are kept only in the groups whose group
|
||||
number is either 0 or a power of 3, 5, or 7. If the flag is not set,
|
||||
redundant copies are kept in all groups.
|
||||
|
@ -27,107 +27,107 @@ The ext4 superblock is laid out as follows in
|
|||
- Name
|
||||
- Description
|
||||
* - 0x0
|
||||
- \_\_le32
|
||||
- s\_inodes\_count
|
||||
- __le32
|
||||
- s_inodes_count
|
||||
- Total inode count.
|
||||
* - 0x4
|
||||
- \_\_le32
|
||||
- s\_blocks\_count\_lo
|
||||
- __le32
|
||||
- s_blocks_count_lo
|
||||
- Total block count.
|
||||
* - 0x8
|
||||
- \_\_le32
|
||||
- s\_r\_blocks\_count\_lo
|
||||
- __le32
|
||||
- s_r_blocks_count_lo
|
||||
- This number of blocks can only be allocated by the super-user.
|
||||
* - 0xC
|
||||
- \_\_le32
|
||||
- s\_free\_blocks\_count\_lo
|
||||
- __le32
|
||||
- s_free_blocks_count_lo
|
||||
- Free block count.
|
||||
* - 0x10
|
||||
- \_\_le32
|
||||
- s\_free\_inodes\_count
|
||||
- __le32
|
||||
- s_free_inodes_count
|
||||
- Free inode count.
|
||||
* - 0x14
|
||||
- \_\_le32
|
||||
- s\_first\_data\_block
|
||||
- __le32
|
||||
- s_first_data_block
|
||||
- First data block. This must be at least 1 for 1k-block filesystems and
|
||||
is typically 0 for all other block sizes.
|
||||
* - 0x18
|
||||
- \_\_le32
|
||||
- s\_log\_block\_size
|
||||
- Block size is 2 ^ (10 + s\_log\_block\_size).
|
||||
- __le32
|
||||
- s_log_block_size
|
||||
- Block size is 2 ^ (10 + s_log_block_size).
|
||||
* - 0x1C
|
||||
- \_\_le32
|
||||
- s\_log\_cluster\_size
|
||||
- Cluster size is 2 ^ (10 + s\_log\_cluster\_size) blocks if bigalloc is
|
||||
enabled. Otherwise s\_log\_cluster\_size must equal s\_log\_block\_size.
|
||||
- __le32
|
||||
- s_log_cluster_size
|
||||
- Cluster size is 2 ^ (10 + s_log_cluster_size) blocks if bigalloc is
|
||||
enabled. Otherwise s_log_cluster_size must equal s_log_block_size.
|
||||
* - 0x20
|
||||
- \_\_le32
|
||||
- s\_blocks\_per\_group
|
||||
- __le32
|
||||
- s_blocks_per_group
|
||||
- Blocks per group.
|
||||
* - 0x24
|
||||
- \_\_le32
|
||||
- s\_clusters\_per\_group
|
||||
- __le32
|
||||
- s_clusters_per_group
|
||||
- Clusters per group, if bigalloc is enabled. Otherwise
|
||||
s\_clusters\_per\_group must equal s\_blocks\_per\_group.
|
||||
s_clusters_per_group must equal s_blocks_per_group.
|
||||
* - 0x28
|
||||
- \_\_le32
|
||||
- s\_inodes\_per\_group
|
||||
- __le32
|
||||
- s_inodes_per_group
|
||||
- Inodes per group.
|
||||
* - 0x2C
|
||||
- \_\_le32
|
||||
- s\_mtime
|
||||
- __le32
|
||||
- s_mtime
|
||||
- Mount time, in seconds since the epoch.
|
||||
* - 0x30
|
||||
- \_\_le32
|
||||
- s\_wtime
|
||||
- __le32
|
||||
- s_wtime
|
||||
- Write time, in seconds since the epoch.
|
||||
* - 0x34
|
||||
- \_\_le16
|
||||
- s\_mnt\_count
|
||||
- __le16
|
||||
- s_mnt_count
|
||||
- Number of mounts since the last fsck.
|
||||
* - 0x36
|
||||
- \_\_le16
|
||||
- s\_max\_mnt\_count
|
||||
- __le16
|
||||
- s_max_mnt_count
|
||||
- Number of mounts beyond which a fsck is needed.
|
||||
* - 0x38
|
||||
- \_\_le16
|
||||
- s\_magic
|
||||
- __le16
|
||||
- s_magic
|
||||
- Magic signature, 0xEF53
|
||||
* - 0x3A
|
||||
- \_\_le16
|
||||
- s\_state
|
||||
- __le16
|
||||
- s_state
|
||||
- File system state. See super_state_ for more info.
|
||||
* - 0x3C
|
||||
- \_\_le16
|
||||
- s\_errors
|
||||
- __le16
|
||||
- s_errors
|
||||
- Behaviour when detecting errors. See super_errors_ for more info.
|
||||
* - 0x3E
|
||||
- \_\_le16
|
||||
- s\_minor\_rev\_level
|
||||
- __le16
|
||||
- s_minor_rev_level
|
||||
- Minor revision level.
|
||||
* - 0x40
|
||||
- \_\_le32
|
||||
- s\_lastcheck
|
||||
- __le32
|
||||
- s_lastcheck
|
||||
- Time of last check, in seconds since the epoch.
|
||||
* - 0x44
|
||||
- \_\_le32
|
||||
- s\_checkinterval
|
||||
- __le32
|
||||
- s_checkinterval
|
||||
- Maximum time between checks, in seconds.
|
||||
* - 0x48
|
||||
- \_\_le32
|
||||
- s\_creator\_os
|
||||
- __le32
|
||||
- s_creator_os
|
||||
- Creator OS. See the table super_creator_ for more info.
|
||||
* - 0x4C
|
||||
- \_\_le32
|
||||
- s\_rev\_level
|
||||
- __le32
|
||||
- s_rev_level
|
||||
- Revision level. See the table super_revision_ for more info.
|
||||
* - 0x50
|
||||
- \_\_le16
|
||||
- s\_def\_resuid
|
||||
- __le16
|
||||
- s_def_resuid
|
||||
- Default uid for reserved blocks.
|
||||
* - 0x52
|
||||
- \_\_le16
|
||||
- s\_def\_resgid
|
||||
- __le16
|
||||
- s_def_resgid
|
||||
- Default gid for reserved blocks.
|
||||
* -
|
||||
-
|
||||
|
@ -143,50 +143,50 @@ The ext4 superblock is laid out as follows in
|
|||
about a feature in either the compatible or incompatible feature set, it
|
||||
must abort and not try to meddle with things it doesn't understand...
|
||||
* - 0x54
|
||||
- \_\_le32
|
||||
- s\_first\_ino
|
||||
- __le32
|
||||
- s_first_ino
|
||||
- First non-reserved inode.
|
||||
* - 0x58
|
||||
- \_\_le16
|
||||
- s\_inode\_size
|
||||
- __le16
|
||||
- s_inode_size
|
||||
- Size of inode structure, in bytes.
|
||||
* - 0x5A
|
||||
- \_\_le16
|
||||
- s\_block\_group\_nr
|
||||
- __le16
|
||||
- s_block_group_nr
|
||||
- Block group # of this superblock.
|
||||
* - 0x5C
|
||||
- \_\_le32
|
||||
- s\_feature\_compat
|
||||
- __le32
|
||||
- s_feature_compat
|
||||
- Compatible feature set flags. Kernel can still read/write this fs even
|
||||
if it doesn't understand a flag; fsck should not do that. See the
|
||||
super_compat_ table for more info.
|
||||
* - 0x60
|
||||
- \_\_le32
|
||||
- s\_feature\_incompat
|
||||
- __le32
|
||||
- s_feature_incompat
|
||||
- Incompatible feature set. If the kernel or fsck doesn't understand one
|
||||
of these bits, it should stop. See the super_incompat_ table for more
|
||||
info.
|
||||
* - 0x64
|
||||
- \_\_le32
|
||||
- s\_feature\_ro\_compat
|
||||
- __le32
|
||||
- s_feature_ro_compat
|
||||
- Readonly-compatible feature set. If the kernel doesn't understand one of
|
||||
these bits, it can still mount read-only. See the super_rocompat_ table
|
||||
for more info.
|
||||
* - 0x68
|
||||
- \_\_u8
|
||||
- s\_uuid[16]
|
||||
- __u8
|
||||
- s_uuid[16]
|
||||
- 128-bit UUID for volume.
|
||||
* - 0x78
|
||||
- char
|
||||
- s\_volume\_name[16]
|
||||
- s_volume_name[16]
|
||||
- Volume label.
|
||||
* - 0x88
|
||||
- char
|
||||
- s\_last\_mounted[64]
|
||||
- s_last_mounted[64]
|
||||
- Directory where filesystem was last mounted.
|
||||
* - 0xC8
|
||||
- \_\_le32
|
||||
- s\_algorithm\_usage\_bitmap
|
||||
- __le32
|
||||
- s_algorithm_usage_bitmap
|
||||
- For compression (Not used in e2fsprogs/Linux)
|
||||
* -
|
||||
-
|
||||
|
@ -194,18 +194,18 @@ The ext4 superblock is laid out as follows in
|
|||
- Performance hints. Directory preallocation should only happen if the
|
||||
EXT4_FEATURE_COMPAT_DIR_PREALLOC flag is on.
|
||||
* - 0xCC
|
||||
- \_\_u8
|
||||
- s\_prealloc\_blocks
|
||||
- __u8
|
||||
- s_prealloc_blocks
|
||||
- #. of blocks to try to preallocate for ... files? (Not used in
|
||||
e2fsprogs/Linux)
|
||||
* - 0xCD
|
||||
- \_\_u8
|
||||
- s\_prealloc\_dir\_blocks
|
||||
- __u8
|
||||
- s_prealloc_dir_blocks
|
||||
- #. of blocks to preallocate for directories. (Not used in
|
||||
e2fsprogs/Linux)
|
||||
* - 0xCE
|
||||
- \_\_le16
|
||||
- s\_reserved\_gdt\_blocks
|
||||
- __le16
|
||||
- s_reserved_gdt_blocks
|
||||
- Number of reserved GDT entries for future filesystem expansion.
|
||||
* -
|
||||
-
|
||||
|
@ -213,281 +213,281 @@ The ext4 superblock is laid out as follows in
|
|||
- Journalling support is valid only if EXT4_FEATURE_COMPAT_HAS_JOURNAL is
|
||||
set.
|
||||
* - 0xD0
|
||||
- \_\_u8
|
||||
- s\_journal\_uuid[16]
|
||||
- __u8
|
||||
- s_journal_uuid[16]
|
||||
- UUID of journal superblock
|
||||
* - 0xE0
|
||||
- \_\_le32
|
||||
- s\_journal\_inum
|
||||
- __le32
|
||||
- s_journal_inum
|
||||
- inode number of journal file.
|
||||
* - 0xE4
|
||||
- \_\_le32
|
||||
- s\_journal\_dev
|
||||
- __le32
|
||||
- s_journal_dev
|
||||
- Device number of journal file, if the external journal feature flag is
|
||||
set.
|
||||
* - 0xE8
|
||||
- \_\_le32
|
||||
- s\_last\_orphan
|
||||
- __le32
|
||||
- s_last_orphan
|
||||
- Start of list of orphaned inodes to delete.
|
||||
* - 0xEC
|
||||
- \_\_le32
|
||||
- s\_hash\_seed[4]
|
||||
- __le32
|
||||
- s_hash_seed[4]
|
||||
- HTREE hash seed.
|
||||
* - 0xFC
|
||||
- \_\_u8
|
||||
- s\_def\_hash\_version
|
||||
- __u8
|
||||
- s_def_hash_version
|
||||
- Default hash algorithm to use for directory hashes. See super_def_hash_
|
||||
for more info.
|
||||
* - 0xFD
|
||||
- \_\_u8
|
||||
- s\_jnl\_backup\_type
|
||||
- If this value is 0 or EXT3\_JNL\_BACKUP\_BLOCKS (1), then the
|
||||
- __u8
|
||||
- s_jnl_backup_type
|
||||
- If this value is 0 or EXT3_JNL_BACKUP_BLOCKS (1), then the
|
||||
``s_jnl_blocks`` field contains a duplicate copy of the inode's
|
||||
``i_block[]`` array and ``i_size``.
|
||||
* - 0xFE
|
||||
- \_\_le16
|
||||
- s\_desc\_size
|
||||
- __le16
|
||||
- s_desc_size
|
||||
- Size of group descriptors, in bytes, if the 64bit incompat feature flag
|
||||
is set.
|
||||
* - 0x100
|
||||
- \_\_le32
|
||||
- s\_default\_mount\_opts
|
||||
- __le32
|
||||
- s_default_mount_opts
|
||||
- Default mount options. See the super_mountopts_ table for more info.
|
||||
* - 0x104
|
||||
- \_\_le32
|
||||
- s\_first\_meta\_bg
|
||||
- First metablock block group, if the meta\_bg feature is enabled.
|
||||
- __le32
|
||||
- s_first_meta_bg
|
||||
- First metablock block group, if the meta_bg feature is enabled.
|
||||
* - 0x108
|
||||
- \_\_le32
|
||||
- s\_mkfs\_time
|
||||
- __le32
|
||||
- s_mkfs_time
|
||||
- When the filesystem was created, in seconds since the epoch.
|
||||
* - 0x10C
|
||||
- \_\_le32
|
||||
- s\_jnl\_blocks[17]
|
||||
- __le32
|
||||
- s_jnl_blocks[17]
|
||||
- Backup copy of the journal inode's ``i_block[]`` array in the first 15
|
||||
elements and i\_size\_high and i\_size in the 16th and 17th elements,
|
||||
elements and i_size_high and i_size in the 16th and 17th elements,
|
||||
respectively.
|
||||
* -
|
||||
-
|
||||
-
|
||||
- 64bit support is valid only if EXT4_FEATURE_COMPAT_64BIT is set.
|
||||
* - 0x150
|
||||
- \_\_le32
|
||||
- s\_blocks\_count\_hi
|
||||
- __le32
|
||||
- s_blocks_count_hi
|
||||
- High 32-bits of the block count.
|
||||
* - 0x154
|
||||
- \_\_le32
|
||||
- s\_r\_blocks\_count\_hi
|
||||
- __le32
|
||||
- s_r_blocks_count_hi
|
||||
- High 32-bits of the reserved block count.
|
||||
* - 0x158
|
||||
- \_\_le32
|
||||
- s\_free\_blocks\_count\_hi
|
||||
- __le32
|
||||
- s_free_blocks_count_hi
|
||||
- High 32-bits of the free block count.
|
||||
* - 0x15C
|
||||
- \_\_le16
|
||||
- s\_min\_extra\_isize
|
||||
- __le16
|
||||
- s_min_extra_isize
|
||||
- All inodes have at least # bytes.
|
||||
* - 0x15E
|
||||
- \_\_le16
|
||||
- s\_want\_extra\_isize
|
||||
- __le16
|
||||
- s_want_extra_isize
|
||||
- New inodes should reserve # bytes.
|
||||
* - 0x160
|
||||
- \_\_le32
|
||||
- s\_flags
|
||||
- __le32
|
||||
- s_flags
|
||||
- Miscellaneous flags. See the super_flags_ table for more info.
|
||||
* - 0x164
|
||||
- \_\_le16
|
||||
- s\_raid\_stride
|
||||
- __le16
|
||||
- s_raid_stride
|
||||
- RAID stride. This is the number of logical blocks read from or written
|
||||
to the disk before moving to the next disk. This affects the placement
|
||||
of filesystem metadata, which will hopefully make RAID storage faster.
|
||||
* - 0x166
|
||||
- \_\_le16
|
||||
- s\_mmp\_interval
|
||||
- __le16
|
||||
- s_mmp_interval
|
||||
- #. seconds to wait in multi-mount prevention (MMP) checking. In theory,
|
||||
MMP is a mechanism to record in the superblock which host and device
|
||||
have mounted the filesystem, in order to prevent multiple mounts. This
|
||||
feature does not seem to be implemented...
|
||||
* - 0x168
|
||||
- \_\_le64
|
||||
- s\_mmp\_block
|
||||
- __le64
|
||||
- s_mmp_block
|
||||
- Block # for multi-mount protection data.
|
||||
* - 0x170
|
||||
- \_\_le32
|
||||
- s\_raid\_stripe\_width
|
||||
- __le32
|
||||
- s_raid_stripe_width
|
||||
- RAID stripe width. This is the number of logical blocks read from or
|
||||
written to the disk before coming back to the current disk. This is used
|
||||
by the block allocator to try to reduce the number of read-modify-write
|
||||
operations in a RAID5/6.
|
||||
* - 0x174
|
||||
- \_\_u8
|
||||
- s\_log\_groups\_per\_flex
|
||||
- __u8
|
||||
- s_log_groups_per_flex
|
||||
- Size of a flexible block group is 2 ^ ``s_log_groups_per_flex``.
|
||||
* - 0x175
|
||||
- \_\_u8
|
||||
- s\_checksum\_type
|
||||
- __u8
|
||||
- s_checksum_type
|
||||
- Metadata checksum algorithm type. The only valid value is 1 (crc32c).
|
||||
* - 0x176
|
||||
- \_\_le16
|
||||
- s\_reserved\_pad
|
||||
- __le16
|
||||
- s_reserved_pad
|
||||
-
|
||||
* - 0x178
|
||||
- \_\_le64
|
||||
- s\_kbytes\_written
|
||||
- __le64
|
||||
- s_kbytes_written
|
||||
- Number of KiB written to this filesystem over its lifetime.
|
||||
* - 0x180
|
||||
- \_\_le32
|
||||
- s\_snapshot\_inum
|
||||
- __le32
|
||||
- s_snapshot_inum
|
||||
- inode number of active snapshot. (Not used in e2fsprogs/Linux.)
|
||||
* - 0x184
|
||||
- \_\_le32
|
||||
- s\_snapshot\_id
|
||||
- __le32
|
||||
- s_snapshot_id
|
||||
- Sequential ID of active snapshot. (Not used in e2fsprogs/Linux.)
|
||||
* - 0x188
|
||||
- \_\_le64
|
||||
- s\_snapshot\_r\_blocks\_count
|
||||
- __le64
|
||||
- s_snapshot_r_blocks_count
|
||||
- Number of blocks reserved for active snapshot's future use. (Not used in
|
||||
e2fsprogs/Linux.)
|
||||
* - 0x190
|
||||
- \_\_le32
|
||||
- s\_snapshot\_list
|
||||
- __le32
|
||||
- s_snapshot_list
|
||||
- inode number of the head of the on-disk snapshot list. (Not used in
|
||||
e2fsprogs/Linux.)
|
||||
* - 0x194
|
||||
- \_\_le32
|
||||
- s\_error\_count
|
||||
- __le32
|
||||
- s_error_count
|
||||
- Number of errors seen.
|
||||
* - 0x198
|
||||
- \_\_le32
|
||||
- s\_first\_error\_time
|
||||
- __le32
|
||||
- s_first_error_time
|
||||
- First time an error happened, in seconds since the epoch.
|
||||
* - 0x19C
|
||||
- \_\_le32
|
||||
- s\_first\_error\_ino
|
||||
- __le32
|
||||
- s_first_error_ino
|
||||
- inode involved in first error.
|
||||
* - 0x1A0
|
||||
- \_\_le64
|
||||
- s\_first\_error\_block
|
||||
- __le64
|
||||
- s_first_error_block
|
||||
- Number of block involved of first error.
|
||||
* - 0x1A8
|
||||
- \_\_u8
|
||||
- s\_first\_error\_func[32]
|
||||
- __u8
|
||||
- s_first_error_func[32]
|
||||
- Name of function where the error happened.
|
||||
* - 0x1C8
|
||||
- \_\_le32
|
||||
- s\_first\_error\_line
|
||||
- __le32
|
||||
- s_first_error_line
|
||||
- Line number where error happened.
|
||||
* - 0x1CC
|
||||
- \_\_le32
|
||||
- s\_last\_error\_time
|
||||
- __le32
|
||||
- s_last_error_time
|
||||
- Time of most recent error, in seconds since the epoch.
|
||||
* - 0x1D0
|
||||
- \_\_le32
|
||||
- s\_last\_error\_ino
|
||||
- __le32
|
||||
- s_last_error_ino
|
||||
- inode involved in most recent error.
|
||||
* - 0x1D4
|
||||
- \_\_le32
|
||||
- s\_last\_error\_line
|
||||
- __le32
|
||||
- s_last_error_line
|
||||
- Line number where most recent error happened.
|
||||
* - 0x1D8
|
||||
- \_\_le64
|
||||
- s\_last\_error\_block
|
||||
- __le64
|
||||
- s_last_error_block
|
||||
- Number of block involved in most recent error.
|
||||
* - 0x1E0
|
||||
- \_\_u8
|
||||
- s\_last\_error\_func[32]
|
||||
- __u8
|
||||
- s_last_error_func[32]
|
||||
- Name of function where the most recent error happened.
|
||||
* - 0x200
|
||||
- \_\_u8
|
||||
- s\_mount\_opts[64]
|
||||
- __u8
|
||||
- s_mount_opts[64]
|
||||
- ASCIIZ string of mount options.
|
||||
* - 0x240
|
||||
- \_\_le32
|
||||
- s\_usr\_quota\_inum
|
||||
- __le32
|
||||
- s_usr_quota_inum
|
||||
- Inode number of user `quota <quota>`__ file.
|
||||
* - 0x244
|
||||
- \_\_le32
|
||||
- s\_grp\_quota\_inum
|
||||
- __le32
|
||||
- s_grp_quota_inum
|
||||
- Inode number of group `quota <quota>`__ file.
|
||||
* - 0x248
|
||||
- \_\_le32
|
||||
- s\_overhead\_blocks
|
||||
- __le32
|
||||
- s_overhead_blocks
|
||||
- Overhead blocks/clusters in fs. (Huh? This field is always zero, which
|
||||
means that the kernel calculates it dynamically.)
|
||||
* - 0x24C
|
||||
- \_\_le32
|
||||
- s\_backup\_bgs[2]
|
||||
- Block groups containing superblock backups (if sparse\_super2)
|
||||
- __le32
|
||||
- s_backup_bgs[2]
|
||||
- Block groups containing superblock backups (if sparse_super2)
|
||||
* - 0x254
|
||||
- \_\_u8
|
||||
- s\_encrypt\_algos[4]
|
||||
- __u8
|
||||
- s_encrypt_algos[4]
|
||||
- Encryption algorithms in use. There can be up to four algorithms in use
|
||||
at any time; valid algorithm codes are given in the super_encrypt_ table
|
||||
below.
|
||||
* - 0x258
|
||||
- \_\_u8
|
||||
- s\_encrypt\_pw\_salt[16]
|
||||
- __u8
|
||||
- s_encrypt_pw_salt[16]
|
||||
- Salt for the string2key algorithm for encryption.
|
||||
* - 0x268
|
||||
- \_\_le32
|
||||
- s\_lpf\_ino
|
||||
- __le32
|
||||
- s_lpf_ino
|
||||
- Inode number of lost+found
|
||||
* - 0x26C
|
||||
- \_\_le32
|
||||
- s\_prj\_quota\_inum
|
||||
- __le32
|
||||
- s_prj_quota_inum
|
||||
- Inode that tracks project quotas.
|
||||
* - 0x270
|
||||
- \_\_le32
|
||||
- s\_checksum\_seed
|
||||
- Checksum seed used for metadata\_csum calculations. This value is
|
||||
crc32c(~0, $orig\_fs\_uuid).
|
||||
- __le32
|
||||
- s_checksum_seed
|
||||
- Checksum seed used for metadata_csum calculations. This value is
|
||||
crc32c(~0, $orig_fs_uuid).
|
||||
* - 0x274
|
||||
- \_\_u8
|
||||
- s\_wtime_hi
|
||||
- __u8
|
||||
- s_wtime_hi
|
||||
- Upper 8 bits of the s_wtime field.
|
||||
* - 0x275
|
||||
- \_\_u8
|
||||
- s\_mtime_hi
|
||||
- __u8
|
||||
- s_mtime_hi
|
||||
- Upper 8 bits of the s_mtime field.
|
||||
* - 0x276
|
||||
- \_\_u8
|
||||
- s\_mkfs_time_hi
|
||||
- __u8
|
||||
- s_mkfs_time_hi
|
||||
- Upper 8 bits of the s_mkfs_time field.
|
||||
* - 0x277
|
||||
- \_\_u8
|
||||
- s\_lastcheck_hi
|
||||
- __u8
|
||||
- s_lastcheck_hi
|
||||
- Upper 8 bits of the s_lastcheck_hi field.
|
||||
* - 0x278
|
||||
- \_\_u8
|
||||
- s\_first_error_time_hi
|
||||
- __u8
|
||||
- s_first_error_time_hi
|
||||
- Upper 8 bits of the s_first_error_time_hi field.
|
||||
* - 0x279
|
||||
- \_\_u8
|
||||
- s\_last_error_time_hi
|
||||
- __u8
|
||||
- s_last_error_time_hi
|
||||
- Upper 8 bits of the s_last_error_time_hi field.
|
||||
* - 0x27A
|
||||
- \_\_u8
|
||||
- s\_pad[2]
|
||||
- __u8
|
||||
- s_pad[2]
|
||||
- Zero padding.
|
||||
* - 0x27C
|
||||
- \_\_le16
|
||||
- s\_encoding
|
||||
- __le16
|
||||
- s_encoding
|
||||
- Filename charset encoding.
|
||||
* - 0x27E
|
||||
- \_\_le16
|
||||
- s\_encoding_flags
|
||||
- __le16
|
||||
- s_encoding_flags
|
||||
- Filename charset encoding flags.
|
||||
* - 0x280
|
||||
- \_\_le32
|
||||
- s\_orphan\_file\_inum
|
||||
- __le32
|
||||
- s_orphan_file_inum
|
||||
- Orphan file inode number.
|
||||
* - 0x284
|
||||
- \_\_le32
|
||||
- s\_reserved[94]
|
||||
- __le32
|
||||
- s_reserved[94]
|
||||
- Padding to the end of the block.
|
||||
* - 0x3FC
|
||||
- \_\_le32
|
||||
- s\_checksum
|
||||
- __le32
|
||||
- s_checksum
|
||||
- Superblock checksum.
|
||||
|
||||
.. _super_state:
|
||||
|
@ -574,44 +574,44 @@ following:
|
|||
* - Value
|
||||
- Description
|
||||
* - 0x1
|
||||
- Directory preallocation (COMPAT\_DIR\_PREALLOC).
|
||||
- Directory preallocation (COMPAT_DIR_PREALLOC).
|
||||
* - 0x2
|
||||
- “imagic inodes”. Not clear from the code what this does
|
||||
(COMPAT\_IMAGIC\_INODES).
|
||||
(COMPAT_IMAGIC_INODES).
|
||||
* - 0x4
|
||||
- Has a journal (COMPAT\_HAS\_JOURNAL).
|
||||
- Has a journal (COMPAT_HAS_JOURNAL).
|
||||
* - 0x8
|
||||
- Supports extended attributes (COMPAT\_EXT\_ATTR).
|
||||
- Supports extended attributes (COMPAT_EXT_ATTR).
|
||||
* - 0x10
|
||||
- Has reserved GDT blocks for filesystem expansion
|
||||
(COMPAT\_RESIZE\_INODE). Requires RO\_COMPAT\_SPARSE\_SUPER.
|
||||
(COMPAT_RESIZE_INODE). Requires RO_COMPAT_SPARSE_SUPER.
|
||||
* - 0x20
|
||||
- Has directory indices (COMPAT\_DIR\_INDEX).
|
||||
- Has directory indices (COMPAT_DIR_INDEX).
|
||||
* - 0x40
|
||||
- “Lazy BG”. Not in Linux kernel, seems to have been for uninitialized
|
||||
block groups? (COMPAT\_LAZY\_BG)
|
||||
block groups? (COMPAT_LAZY_BG)
|
||||
* - 0x80
|
||||
- “Exclude inode”. Not used. (COMPAT\_EXCLUDE\_INODE).
|
||||
- “Exclude inode”. Not used. (COMPAT_EXCLUDE_INODE).
|
||||
* - 0x100
|
||||
- “Exclude bitmap”. Seems to be used to indicate the presence of
|
||||
snapshot-related exclude bitmaps? Not defined in kernel or used in
|
||||
e2fsprogs (COMPAT\_EXCLUDE\_BITMAP).
|
||||
e2fsprogs (COMPAT_EXCLUDE_BITMAP).
|
||||
* - 0x200
|
||||
- Sparse Super Block, v2. If this flag is set, the SB field s\_backup\_bgs
|
||||
- Sparse Super Block, v2. If this flag is set, the SB field s_backup_bgs
|
||||
points to the two block groups that contain backup superblocks
|
||||
(COMPAT\_SPARSE\_SUPER2).
|
||||
(COMPAT_SPARSE_SUPER2).
|
||||
* - 0x400
|
||||
- Fast commits supported. Although fast commits blocks are
|
||||
backward incompatible, fast commit blocks are not always
|
||||
present in the journal. If fast commit blocks are present in
|
||||
the journal, JBD2 incompat feature
|
||||
(JBD2\_FEATURE\_INCOMPAT\_FAST\_COMMIT) gets
|
||||
set (COMPAT\_FAST\_COMMIT).
|
||||
(JBD2_FEATURE_INCOMPAT_FAST_COMMIT) gets
|
||||
set (COMPAT_FAST_COMMIT).
|
||||
* - 0x1000
|
||||
- Orphan file allocated. This is the special file for more efficient
|
||||
tracking of unlinked but still open inodes. When there may be any
|
||||
entries in the file, we additionally set proper rocompat feature
|
||||
(RO\_COMPAT\_ORPHAN\_PRESENT).
|
||||
(RO_COMPAT_ORPHAN_PRESENT).
|
||||
|
||||
.. _super_incompat:
|
||||
|
||||
|
@ -625,45 +625,45 @@ following:
|
|||
* - Value
|
||||
- Description
|
||||
* - 0x1
|
||||
- Compression (INCOMPAT\_COMPRESSION).
|
||||
- Compression (INCOMPAT_COMPRESSION).
|
||||
* - 0x2
|
||||
- Directory entries record the file type. See ext4\_dir\_entry\_2 below
|
||||
(INCOMPAT\_FILETYPE).
|
||||
- Directory entries record the file type. See ext4_dir_entry_2 below
|
||||
(INCOMPAT_FILETYPE).
|
||||
* - 0x4
|
||||
- Filesystem needs recovery (INCOMPAT\_RECOVER).
|
||||
- Filesystem needs recovery (INCOMPAT_RECOVER).
|
||||
* - 0x8
|
||||
- Filesystem has a separate journal device (INCOMPAT\_JOURNAL\_DEV).
|
||||
- Filesystem has a separate journal device (INCOMPAT_JOURNAL_DEV).
|
||||
* - 0x10
|
||||
- Meta block groups. See the earlier discussion of this feature
|
||||
(INCOMPAT\_META\_BG).
|
||||
(INCOMPAT_META_BG).
|
||||
* - 0x40
|
||||
- Files in this filesystem use extents (INCOMPAT\_EXTENTS).
|
||||
- Files in this filesystem use extents (INCOMPAT_EXTENTS).
|
||||
* - 0x80
|
||||
- Enable a filesystem size of 2^64 blocks (INCOMPAT\_64BIT).
|
||||
- Enable a filesystem size of 2^64 blocks (INCOMPAT_64BIT).
|
||||
* - 0x100
|
||||
- Multiple mount protection (INCOMPAT\_MMP).
|
||||
- Multiple mount protection (INCOMPAT_MMP).
|
||||
* - 0x200
|
||||
- Flexible block groups. See the earlier discussion of this feature
|
||||
(INCOMPAT\_FLEX\_BG).
|
||||
(INCOMPAT_FLEX_BG).
|
||||
* - 0x400
|
||||
- Inodes can be used to store large extended attribute values
|
||||
(INCOMPAT\_EA\_INODE).
|
||||
(INCOMPAT_EA_INODE).
|
||||
* - 0x1000
|
||||
- Data in directory entry (INCOMPAT\_DIRDATA). (Not implemented?)
|
||||
- Data in directory entry (INCOMPAT_DIRDATA). (Not implemented?)
|
||||
* - 0x2000
|
||||
- Metadata checksum seed is stored in the superblock. This feature enables
|
||||
the administrator to change the UUID of a metadata\_csum filesystem
|
||||
the administrator to change the UUID of a metadata_csum filesystem
|
||||
while the filesystem is mounted; without it, the checksum definition
|
||||
requires all metadata blocks to be rewritten (INCOMPAT\_CSUM\_SEED).
|
||||
requires all metadata blocks to be rewritten (INCOMPAT_CSUM_SEED).
|
||||
* - 0x4000
|
||||
- Large directory >2GB or 3-level htree (INCOMPAT\_LARGEDIR). Prior to
|
||||
- Large directory >2GB or 3-level htree (INCOMPAT_LARGEDIR). Prior to
|
||||
this feature, directories could not be larger than 4GiB and could not
|
||||
have an htree more than 2 levels deep. If this feature is enabled,
|
||||
directories can be larger than 4GiB and have a maximum htree depth of 3.
|
||||
* - 0x8000
|
||||
- Data in inode (INCOMPAT\_INLINE\_DATA).
|
||||
- Data in inode (INCOMPAT_INLINE_DATA).
|
||||
* - 0x10000
|
||||
- Encrypted inodes are present on the filesystem. (INCOMPAT\_ENCRYPT).
|
||||
- Encrypted inodes are present on the filesystem. (INCOMPAT_ENCRYPT).
|
||||
|
||||
.. _super_rocompat:
|
||||
|
||||
|
@ -678,54 +678,54 @@ the following:
|
|||
- Description
|
||||
* - 0x1
|
||||
- Sparse superblocks. See the earlier discussion of this feature
|
||||
(RO\_COMPAT\_SPARSE\_SUPER).
|
||||
(RO_COMPAT_SPARSE_SUPER).
|
||||
* - 0x2
|
||||
- This filesystem has been used to store a file greater than 2GiB
|
||||
(RO\_COMPAT\_LARGE\_FILE).
|
||||
(RO_COMPAT_LARGE_FILE).
|
||||
* - 0x4
|
||||
- Not used in kernel or e2fsprogs (RO\_COMPAT\_BTREE\_DIR).
|
||||
- Not used in kernel or e2fsprogs (RO_COMPAT_BTREE_DIR).
|
||||
* - 0x8
|
||||
- This filesystem has files whose sizes are represented in units of
|
||||
logical blocks, not 512-byte sectors. This implies a very large file
|
||||
indeed! (RO\_COMPAT\_HUGE\_FILE)
|
||||
indeed! (RO_COMPAT_HUGE_FILE)
|
||||
* - 0x10
|
||||
- Group descriptors have checksums. In addition to detecting corruption,
|
||||
this is useful for lazy formatting with uninitialized groups
|
||||
(RO\_COMPAT\_GDT\_CSUM).
|
||||
(RO_COMPAT_GDT_CSUM).
|
||||
* - 0x20
|
||||
- Indicates that the old ext3 32,000 subdirectory limit no longer applies
|
||||
(RO\_COMPAT\_DIR\_NLINK). A directory's i\_links\_count will be set to 1
|
||||
(RO_COMPAT_DIR_NLINK). A directory's i_links_count will be set to 1
|
||||
if it is incremented past 64,999.
|
||||
* - 0x40
|
||||
- Indicates that large inodes exist on this filesystem
|
||||
(RO\_COMPAT\_EXTRA\_ISIZE).
|
||||
(RO_COMPAT_EXTRA_ISIZE).
|
||||
* - 0x80
|
||||
- This filesystem has a snapshot (RO\_COMPAT\_HAS\_SNAPSHOT).
|
||||
- This filesystem has a snapshot (RO_COMPAT_HAS_SNAPSHOT).
|
||||
* - 0x100
|
||||
- `Quota <Quota>`__ (RO\_COMPAT\_QUOTA).
|
||||
- `Quota <Quota>`__ (RO_COMPAT_QUOTA).
|
||||
* - 0x200
|
||||
- This filesystem supports “bigalloc”, which means that file extents are
|
||||
tracked in units of clusters (of blocks) instead of blocks
|
||||
(RO\_COMPAT\_BIGALLOC).
|
||||
(RO_COMPAT_BIGALLOC).
|
||||
* - 0x400
|
||||
- This filesystem supports metadata checksumming.
|
||||
(RO\_COMPAT\_METADATA\_CSUM; implies RO\_COMPAT\_GDT\_CSUM, though
|
||||
GDT\_CSUM must not be set)
|
||||
(RO_COMPAT_METADATA_CSUM; implies RO_COMPAT_GDT_CSUM, though
|
||||
GDT_CSUM must not be set)
|
||||
* - 0x800
|
||||
- Filesystem supports replicas. This feature is neither in the kernel nor
|
||||
e2fsprogs. (RO\_COMPAT\_REPLICA)
|
||||
e2fsprogs. (RO_COMPAT_REPLICA)
|
||||
* - 0x1000
|
||||
- Read-only filesystem image; the kernel will not mount this image
|
||||
read-write and most tools will refuse to write to the image.
|
||||
(RO\_COMPAT\_READONLY)
|
||||
(RO_COMPAT_READONLY)
|
||||
* - 0x2000
|
||||
- Filesystem tracks project quotas. (RO\_COMPAT\_PROJECT)
|
||||
- Filesystem tracks project quotas. (RO_COMPAT_PROJECT)
|
||||
* - 0x8000
|
||||
- Verity inodes may be present on the filesystem. (RO\_COMPAT\_VERITY)
|
||||
- Verity inodes may be present on the filesystem. (RO_COMPAT_VERITY)
|
||||
* - 0x10000
|
||||
- Indicates orphan file may have valid orphan entries and thus we need
|
||||
to clean them up when mounting the filesystem
|
||||
(RO\_COMPAT\_ORPHAN\_PRESENT).
|
||||
(RO_COMPAT_ORPHAN_PRESENT).
|
||||
|
||||
.. _super_def_hash:
|
||||
|
||||
|
@ -761,36 +761,36 @@ The ``s_default_mount_opts`` field is any combination of the following:
|
|||
* - Value
|
||||
- Description
|
||||
* - 0x0001
|
||||
- Print debugging info upon (re)mount. (EXT4\_DEFM\_DEBUG)
|
||||
- Print debugging info upon (re)mount. (EXT4_DEFM_DEBUG)
|
||||
* - 0x0002
|
||||
- New files take the gid of the containing directory (instead of the fsgid
|
||||
of the current process). (EXT4\_DEFM\_BSDGROUPS)
|
||||
of the current process). (EXT4_DEFM_BSDGROUPS)
|
||||
* - 0x0004
|
||||
- Support userspace-provided extended attributes. (EXT4\_DEFM\_XATTR\_USER)
|
||||
- Support userspace-provided extended attributes. (EXT4_DEFM_XATTR_USER)
|
||||
* - 0x0008
|
||||
- Support POSIX access control lists (ACLs). (EXT4\_DEFM\_ACL)
|
||||
- Support POSIX access control lists (ACLs). (EXT4_DEFM_ACL)
|
||||
* - 0x0010
|
||||
- Do not support 32-bit UIDs. (EXT4\_DEFM\_UID16)
|
||||
- Do not support 32-bit UIDs. (EXT4_DEFM_UID16)
|
||||
* - 0x0020
|
||||
- All data and metadata are commited to the journal.
|
||||
(EXT4\_DEFM\_JMODE\_DATA)
|
||||
(EXT4_DEFM_JMODE_DATA)
|
||||
* - 0x0040
|
||||
- All data are flushed to the disk before metadata are committed to the
|
||||
journal. (EXT4\_DEFM\_JMODE\_ORDERED)
|
||||
journal. (EXT4_DEFM_JMODE_ORDERED)
|
||||
* - 0x0060
|
||||
- Data ordering is not preserved; data may be written after the metadata
|
||||
has been written. (EXT4\_DEFM\_JMODE\_WBACK)
|
||||
has been written. (EXT4_DEFM_JMODE_WBACK)
|
||||
* - 0x0100
|
||||
- Disable write flushes. (EXT4\_DEFM\_NOBARRIER)
|
||||
- Disable write flushes. (EXT4_DEFM_NOBARRIER)
|
||||
* - 0x0200
|
||||
- Track which blocks in a filesystem are metadata and therefore should not
|
||||
be used as data blocks. This option will be enabled by default on 3.18,
|
||||
hopefully. (EXT4\_DEFM\_BLOCK\_VALIDITY)
|
||||
hopefully. (EXT4_DEFM_BLOCK_VALIDITY)
|
||||
* - 0x0400
|
||||
- Enable DISCARD support, where the storage device is told about blocks
|
||||
becoming unused. (EXT4\_DEFM\_DISCARD)
|
||||
becoming unused. (EXT4_DEFM_DISCARD)
|
||||
* - 0x0800
|
||||
- Disable delayed allocation. (EXT4\_DEFM\_NODELALLOC)
|
||||
- Disable delayed allocation. (EXT4_DEFM_NODELALLOC)
|
||||
|
||||
.. _super_flags:
|
||||
|
||||
|
@ -820,12 +820,12 @@ The ``s_encrypt_algos`` list can contain any of the following:
|
|||
* - Value
|
||||
- Description
|
||||
* - 0
|
||||
- Invalid algorithm (ENCRYPTION\_MODE\_INVALID).
|
||||
- Invalid algorithm (ENCRYPTION_MODE_INVALID).
|
||||
* - 1
|
||||
- 256-bit AES in XTS mode (ENCRYPTION\_MODE\_AES\_256\_XTS).
|
||||
- 256-bit AES in XTS mode (ENCRYPTION_MODE_AES_256_XTS).
|
||||
* - 2
|
||||
- 256-bit AES in GCM mode (ENCRYPTION\_MODE\_AES\_256\_GCM).
|
||||
- 256-bit AES in GCM mode (ENCRYPTION_MODE_AES_256_GCM).
|
||||
* - 3
|
||||
- 256-bit AES in CBC mode (ENCRYPTION\_MODE\_AES\_256\_CBC).
|
||||
- 256-bit AES in CBC mode (ENCRYPTION_MODE_AES_256_CBC).
|
||||
|
||||
Total size of the superblock is 1024 bytes.
|
||||
|
|
|
@ -829,7 +829,7 @@ int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
|
|||
ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
|
||||
inode->i_ino, create);
|
||||
return _ext4_get_block(inode, iblock, bh_result,
|
||||
EXT4_GET_BLOCKS_IO_CREATE_EXT);
|
||||
EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT);
|
||||
}
|
||||
|
||||
/* Maximum number of blocks we map for direct IO at once. */
|
||||
|
|
|
@ -4104,6 +4104,15 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
|
|||
size = size >> bsbits;
|
||||
start = start_off >> bsbits;
|
||||
|
||||
/*
|
||||
* For tiny groups (smaller than 8MB) the chosen allocation
|
||||
* alignment may be larger than group size. Make sure the
|
||||
* alignment does not move allocation to a different group which
|
||||
* makes mballoc fail assertions later.
|
||||
*/
|
||||
start = max(start, rounddown(ac->ac_o_ex.fe_logical,
|
||||
(ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb)));
|
||||
|
||||
/* don't cover already allocated blocks in selected range */
|
||||
if (ar->pleft && start <= ar->lleft) {
|
||||
size -= ar->lleft + 1 - start;
|
||||
|
@ -4176,7 +4185,22 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
|
|||
}
|
||||
rcu_read_unlock();
|
||||
|
||||
if (start + size <= ac->ac_o_ex.fe_logical &&
|
||||
/*
|
||||
* In this function "start" and "size" are normalized for better
|
||||
* alignment and length such that we could preallocate more blocks.
|
||||
* This normalization is done such that original request of
|
||||
* ac->ac_o_ex.fe_logical & fe_len should always lie within "start" and
|
||||
* "size" boundaries.
|
||||
* (Note fe_len can be relaxed since FS block allocation API does not
|
||||
* provide gurantee on number of contiguous blocks allocation since that
|
||||
* depends upon free space left, etc).
|
||||
* In case of inode pa, later we use the allocated blocks
|
||||
* [pa_start + fe_logical - pa_lstart, fe_len/size] from the preallocated
|
||||
* range of goal/best blocks [start, size] to put it at the
|
||||
* ac_o_ex.fe_logical extent of this inode.
|
||||
* (See ext4_mb_use_inode_pa() for more details)
|
||||
*/
|
||||
if (start + size <= ac->ac_o_ex.fe_logical ||
|
||||
start > ac->ac_o_ex.fe_logical) {
|
||||
ext4_msg(ac->ac_sb, KERN_ERR,
|
||||
"start %lu, size %lu, fe_logical %lu",
|
||||
|
|
|
@ -438,7 +438,7 @@ int ext4_ext_migrate(struct inode *inode)
|
|||
|
||||
/*
|
||||
* Worst case we can touch the allocation bitmaps and a block
|
||||
* group descriptor block. We do need need to worry about
|
||||
* group descriptor block. We do need to worry about
|
||||
* credits for modifying the quota inode.
|
||||
*/
|
||||
handle = ext4_journal_start(inode, EXT4_HT_MIGRATE,
|
||||
|
|
|
@ -1929,7 +1929,8 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
|
|||
struct dx_hash_info *hinfo)
|
||||
{
|
||||
unsigned blocksize = dir->i_sb->s_blocksize;
|
||||
unsigned count, continued;
|
||||
unsigned continued;
|
||||
int count;
|
||||
struct buffer_head *bh2;
|
||||
ext4_lblk_t newblock;
|
||||
u32 hash2;
|
||||
|
|
|
@ -465,7 +465,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
|
|||
/*
|
||||
* In the first loop we prepare and mark buffers to submit. We have to
|
||||
* mark all buffers in the page before submitting so that
|
||||
* end_page_writeback() cannot be called from ext4_bio_end_io() when IO
|
||||
* end_page_writeback() cannot be called from ext4_end_bio() when IO
|
||||
* on the first buffer finishes and we are still working on submitting
|
||||
* the second buffer.
|
||||
*/
|
||||
|
|
|
@ -53,6 +53,16 @@ int ext4_resize_begin(struct super_block *sb)
|
|||
if (!capable(CAP_SYS_RESOURCE))
|
||||
return -EPERM;
|
||||
|
||||
/*
|
||||
* If the reserved GDT blocks is non-zero, the resize_inode feature
|
||||
* should always be set.
|
||||
*/
|
||||
if (EXT4_SB(sb)->s_es->s_reserved_gdt_blocks &&
|
||||
!ext4_has_feature_resize_inode(sb)) {
|
||||
ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
|
||||
return -EFSCORRUPTED;
|
||||
}
|
||||
|
||||
/*
|
||||
* If we are not using the primary superblock/GDT copy don't resize,
|
||||
* because the user tools have no way of handling this. Probably a
|
||||
|
|
172
fs/ext4/super.c
172
fs/ext4/super.c
|
@ -87,7 +87,7 @@ static struct inode *ext4_get_journal_inode(struct super_block *sb,
|
|||
static int ext4_validate_options(struct fs_context *fc);
|
||||
static int ext4_check_opt_consistency(struct fs_context *fc,
|
||||
struct super_block *sb);
|
||||
static int ext4_apply_options(struct fs_context *fc, struct super_block *sb);
|
||||
static void ext4_apply_options(struct fs_context *fc, struct super_block *sb);
|
||||
static int ext4_parse_param(struct fs_context *fc, struct fs_parameter *param);
|
||||
static int ext4_get_tree(struct fs_context *fc);
|
||||
static int ext4_reconfigure(struct fs_context *fc);
|
||||
|
@ -1870,31 +1870,12 @@ ext4_sb_read_encoding(const struct ext4_super_block *es)
|
|||
}
|
||||
#endif
|
||||
|
||||
static int ext4_set_test_dummy_encryption(struct super_block *sb, char *arg)
|
||||
{
|
||||
#ifdef CONFIG_FS_ENCRYPTION
|
||||
struct ext4_sb_info *sbi = EXT4_SB(sb);
|
||||
int err;
|
||||
|
||||
err = fscrypt_set_test_dummy_encryption(sb, arg,
|
||||
&sbi->s_dummy_enc_policy);
|
||||
if (err) {
|
||||
ext4_msg(sb, KERN_WARNING,
|
||||
"Error while setting test dummy encryption [%d]", err);
|
||||
return err;
|
||||
}
|
||||
ext4_msg(sb, KERN_WARNING, "Test dummy encryption mode enabled");
|
||||
#endif
|
||||
return 0;
|
||||
}
|
||||
|
||||
#define EXT4_SPEC_JQUOTA (1 << 0)
|
||||
#define EXT4_SPEC_JQFMT (1 << 1)
|
||||
#define EXT4_SPEC_DATAJ (1 << 2)
|
||||
#define EXT4_SPEC_SB_BLOCK (1 << 3)
|
||||
#define EXT4_SPEC_JOURNAL_DEV (1 << 4)
|
||||
#define EXT4_SPEC_JOURNAL_IOPRIO (1 << 5)
|
||||
#define EXT4_SPEC_DUMMY_ENCRYPTION (1 << 6)
|
||||
#define EXT4_SPEC_s_want_extra_isize (1 << 7)
|
||||
#define EXT4_SPEC_s_max_batch_time (1 << 8)
|
||||
#define EXT4_SPEC_s_min_batch_time (1 << 9)
|
||||
|
@ -1911,7 +1892,7 @@ static int ext4_set_test_dummy_encryption(struct super_block *sb, char *arg)
|
|||
|
||||
struct ext4_fs_context {
|
||||
char *s_qf_names[EXT4_MAXQUOTAS];
|
||||
char *test_dummy_enc_arg;
|
||||
struct fscrypt_dummy_policy dummy_enc_policy;
|
||||
int s_jquota_fmt; /* Format of quota to use */
|
||||
#ifdef CONFIG_EXT4_DEBUG
|
||||
int s_fc_debug_max_replay;
|
||||
|
@ -1953,7 +1934,7 @@ static void ext4_fc_free(struct fs_context *fc)
|
|||
for (i = 0; i < EXT4_MAXQUOTAS; i++)
|
||||
kfree(ctx->s_qf_names[i]);
|
||||
|
||||
kfree(ctx->test_dummy_enc_arg);
|
||||
fscrypt_free_dummy_policy(&ctx->dummy_enc_policy);
|
||||
kfree(ctx);
|
||||
}
|
||||
|
||||
|
@ -2029,6 +2010,29 @@ static int unnote_qf_name(struct fs_context *fc, int qtype)
|
|||
}
|
||||
#endif
|
||||
|
||||
static int ext4_parse_test_dummy_encryption(const struct fs_parameter *param,
|
||||
struct ext4_fs_context *ctx)
|
||||
{
|
||||
int err;
|
||||
|
||||
if (!IS_ENABLED(CONFIG_FS_ENCRYPTION)) {
|
||||
ext4_msg(NULL, KERN_WARNING,
|
||||
"test_dummy_encryption option not supported");
|
||||
return -EINVAL;
|
||||
}
|
||||
err = fscrypt_parse_test_dummy_encryption(param,
|
||||
&ctx->dummy_enc_policy);
|
||||
if (err == -EINVAL) {
|
||||
ext4_msg(NULL, KERN_WARNING,
|
||||
"Value of option \"%s\" is unrecognized", param->key);
|
||||
} else if (err == -EEXIST) {
|
||||
ext4_msg(NULL, KERN_WARNING,
|
||||
"Conflicting test_dummy_encryption options");
|
||||
return -EINVAL;
|
||||
}
|
||||
return err;
|
||||
}
|
||||
|
||||
#define EXT4_SET_CTX(name) \
|
||||
static inline void ctx_set_##name(struct ext4_fs_context *ctx, \
|
||||
unsigned long flag) \
|
||||
|
@ -2291,29 +2295,7 @@ static int ext4_parse_param(struct fs_context *fc, struct fs_parameter *param)
|
|||
ctx->spec |= EXT4_SPEC_JOURNAL_IOPRIO;
|
||||
return 0;
|
||||
case Opt_test_dummy_encryption:
|
||||
#ifdef CONFIG_FS_ENCRYPTION
|
||||
if (param->type == fs_value_is_flag) {
|
||||
ctx->spec |= EXT4_SPEC_DUMMY_ENCRYPTION;
|
||||
ctx->test_dummy_enc_arg = NULL;
|
||||
return 0;
|
||||
}
|
||||
if (*param->string &&
|
||||
!(!strcmp(param->string, "v1") ||
|
||||
!strcmp(param->string, "v2"))) {
|
||||
ext4_msg(NULL, KERN_WARNING,
|
||||
"Value of option \"%s\" is unrecognized",
|
||||
param->key);
|
||||
return -EINVAL;
|
||||
}
|
||||
ctx->spec |= EXT4_SPEC_DUMMY_ENCRYPTION;
|
||||
ctx->test_dummy_enc_arg = kmemdup_nul(param->string, param->size,
|
||||
GFP_KERNEL);
|
||||
return 0;
|
||||
#else
|
||||
ext4_msg(NULL, KERN_WARNING,
|
||||
"test_dummy_encryption option not supported");
|
||||
return -EINVAL;
|
||||
#endif
|
||||
return ext4_parse_test_dummy_encryption(param, ctx);
|
||||
case Opt_dax:
|
||||
case Opt_dax_type:
|
||||
#ifdef CONFIG_FS_DAX
|
||||
|
@ -2504,7 +2486,8 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
|
|||
if (s_ctx->spec & EXT4_SPEC_JOURNAL_IOPRIO)
|
||||
m_ctx->journal_ioprio = s_ctx->journal_ioprio;
|
||||
|
||||
ret = ext4_apply_options(fc, sb);
|
||||
ext4_apply_options(fc, sb);
|
||||
ret = 0;
|
||||
|
||||
out_free:
|
||||
if (fc) {
|
||||
|
@ -2673,11 +2656,11 @@ static int ext4_check_quota_consistency(struct fs_context *fc,
|
|||
static int ext4_check_test_dummy_encryption(const struct fs_context *fc,
|
||||
struct super_block *sb)
|
||||
{
|
||||
#ifdef CONFIG_FS_ENCRYPTION
|
||||
const struct ext4_fs_context *ctx = fc->fs_private;
|
||||
const struct ext4_sb_info *sbi = EXT4_SB(sb);
|
||||
int err;
|
||||
|
||||
if (!(ctx->spec & EXT4_SPEC_DUMMY_ENCRYPTION))
|
||||
if (!fscrypt_is_dummy_policy_set(&ctx->dummy_enc_policy))
|
||||
return 0;
|
||||
|
||||
if (!ext4_has_feature_encrypt(sb)) {
|
||||
|
@ -2691,14 +2674,46 @@ static int ext4_check_test_dummy_encryption(const struct fs_context *fc,
|
|||
* needed to allow it to be set or changed during remount. We do allow
|
||||
* it to be specified during remount, but only if there is no change.
|
||||
*/
|
||||
if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE &&
|
||||
!sbi->s_dummy_enc_policy.policy) {
|
||||
if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
|
||||
if (fscrypt_dummy_policies_equal(&sbi->s_dummy_enc_policy,
|
||||
&ctx->dummy_enc_policy))
|
||||
return 0;
|
||||
ext4_msg(NULL, KERN_WARNING,
|
||||
"Can't set test_dummy_encryption on remount");
|
||||
"Can't set or change test_dummy_encryption on remount");
|
||||
return -EINVAL;
|
||||
}
|
||||
#endif /* CONFIG_FS_ENCRYPTION */
|
||||
return 0;
|
||||
/* Also make sure s_mount_opts didn't contain a conflicting value. */
|
||||
if (fscrypt_is_dummy_policy_set(&sbi->s_dummy_enc_policy)) {
|
||||
if (fscrypt_dummy_policies_equal(&sbi->s_dummy_enc_policy,
|
||||
&ctx->dummy_enc_policy))
|
||||
return 0;
|
||||
ext4_msg(NULL, KERN_WARNING,
|
||||
"Conflicting test_dummy_encryption options");
|
||||
return -EINVAL;
|
||||
}
|
||||
/*
|
||||
* fscrypt_add_test_dummy_key() technically changes the super_block, so
|
||||
* technically it should be delayed until ext4_apply_options() like the
|
||||
* other changes. But since we never get here for remounts (see above),
|
||||
* and this is the last chance to report errors, we do it here.
|
||||
*/
|
||||
err = fscrypt_add_test_dummy_key(sb, &ctx->dummy_enc_policy);
|
||||
if (err)
|
||||
ext4_msg(NULL, KERN_WARNING,
|
||||
"Error adding test dummy encryption key [%d]", err);
|
||||
return err;
|
||||
}
|
||||
|
||||
static void ext4_apply_test_dummy_encryption(struct ext4_fs_context *ctx,
|
||||
struct super_block *sb)
|
||||
{
|
||||
if (!fscrypt_is_dummy_policy_set(&ctx->dummy_enc_policy) ||
|
||||
/* if already set, it was already verified to be the same */
|
||||
fscrypt_is_dummy_policy_set(&EXT4_SB(sb)->s_dummy_enc_policy))
|
||||
return;
|
||||
EXT4_SB(sb)->s_dummy_enc_policy = ctx->dummy_enc_policy;
|
||||
memset(&ctx->dummy_enc_policy, 0, sizeof(ctx->dummy_enc_policy));
|
||||
ext4_msg(sb, KERN_WARNING, "Test dummy encryption mode enabled");
|
||||
}
|
||||
|
||||
static int ext4_check_opt_consistency(struct fs_context *fc,
|
||||
|
@ -2785,11 +2800,10 @@ static int ext4_check_opt_consistency(struct fs_context *fc,
|
|||
return ext4_check_quota_consistency(fc, sb);
|
||||
}
|
||||
|
||||
static int ext4_apply_options(struct fs_context *fc, struct super_block *sb)
|
||||
static void ext4_apply_options(struct fs_context *fc, struct super_block *sb)
|
||||
{
|
||||
struct ext4_fs_context *ctx = fc->fs_private;
|
||||
struct ext4_sb_info *sbi = fc->s_fs_info;
|
||||
int ret = 0;
|
||||
|
||||
sbi->s_mount_opt &= ~ctx->mask_s_mount_opt;
|
||||
sbi->s_mount_opt |= ctx->vals_s_mount_opt;
|
||||
|
@ -2825,11 +2839,7 @@ static int ext4_apply_options(struct fs_context *fc, struct super_block *sb)
|
|||
#endif
|
||||
|
||||
ext4_apply_quota_options(fc, sb);
|
||||
|
||||
if (ctx->spec & EXT4_SPEC_DUMMY_ENCRYPTION)
|
||||
ret = ext4_set_test_dummy_encryption(sb, ctx->test_dummy_enc_arg);
|
||||
|
||||
return ret;
|
||||
ext4_apply_test_dummy_encryption(ctx, sb);
|
||||
}
|
||||
|
||||
|
||||
|
@ -4552,9 +4562,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
|
|||
if (err < 0)
|
||||
goto failed_mount;
|
||||
|
||||
err = ext4_apply_options(fc, sb);
|
||||
if (err < 0)
|
||||
goto failed_mount;
|
||||
ext4_apply_options(fc, sb);
|
||||
|
||||
#if IS_ENABLED(CONFIG_UNICODE)
|
||||
if (ext4_has_feature_casefold(sb) && !sb->s_encoding) {
|
||||
|
@ -5302,14 +5310,6 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
|
|||
err = percpu_counter_init(&sbi->s_freeinodes_counter, freei,
|
||||
GFP_KERNEL);
|
||||
}
|
||||
/*
|
||||
* Update the checksum after updating free space/inode
|
||||
* counters. Otherwise the superblock can have an incorrect
|
||||
* checksum in the buffer cache until it is written out and
|
||||
* e2fsprogs programs trying to open a file system immediately
|
||||
* after it is mounted can fail.
|
||||
*/
|
||||
ext4_superblock_csum_set(sb);
|
||||
if (!err)
|
||||
err = percpu_counter_init(&sbi->s_dirs_counter,
|
||||
ext4_count_dirs(sb), GFP_KERNEL);
|
||||
|
@ -5367,6 +5367,14 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
|
|||
EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
|
||||
ext4_orphan_cleanup(sb, es);
|
||||
EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
|
||||
/*
|
||||
* Update the checksum after updating free space/inode counters and
|
||||
* ext4_orphan_cleanup. Otherwise the superblock can have an incorrect
|
||||
* checksum in the buffer cache until it is written out and
|
||||
* e2fsprogs programs trying to open a file system immediately
|
||||
* after it is mounted can fail.
|
||||
*/
|
||||
ext4_superblock_csum_set(sb);
|
||||
if (needs_recovery) {
|
||||
ext4_msg(sb, KERN_INFO, "recovery complete");
|
||||
err = ext4_mark_recovery_complete(sb, es);
|
||||
|
@ -5898,7 +5906,6 @@ static void ext4_update_super(struct super_block *sb)
|
|||
static int ext4_commit_super(struct super_block *sb)
|
||||
{
|
||||
struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
|
||||
int error = 0;
|
||||
|
||||
if (!sbh)
|
||||
return -EINVAL;
|
||||
|
@ -5907,6 +5914,13 @@ static int ext4_commit_super(struct super_block *sb)
|
|||
|
||||
ext4_update_super(sb);
|
||||
|
||||
lock_buffer(sbh);
|
||||
/* Buffer got discarded which means block device got invalidated */
|
||||
if (!buffer_mapped(sbh)) {
|
||||
unlock_buffer(sbh);
|
||||
return -EIO;
|
||||
}
|
||||
|
||||
if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) {
|
||||
/*
|
||||
* Oh, dear. A previous attempt to write the
|
||||
|
@ -5921,17 +5935,21 @@ static int ext4_commit_super(struct super_block *sb)
|
|||
clear_buffer_write_io_error(sbh);
|
||||
set_buffer_uptodate(sbh);
|
||||
}
|
||||
BUFFER_TRACE(sbh, "marking dirty");
|
||||
mark_buffer_dirty(sbh);
|
||||
error = __sync_dirty_buffer(sbh,
|
||||
REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0));
|
||||
get_bh(sbh);
|
||||
/* Clear potential dirty bit if it was journalled update */
|
||||
clear_buffer_dirty(sbh);
|
||||
sbh->b_end_io = end_buffer_write_sync;
|
||||
submit_bh(REQ_OP_WRITE,
|
||||
REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0), sbh);
|
||||
wait_on_buffer(sbh);
|
||||
if (buffer_write_io_error(sbh)) {
|
||||
ext4_msg(sb, KERN_ERR, "I/O error while writing "
|
||||
"superblock");
|
||||
clear_buffer_write_io_error(sbh);
|
||||
set_buffer_uptodate(sbh);
|
||||
return -EIO;
|
||||
}
|
||||
return error;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
|
@ -1895,11 +1895,10 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
|
|||
|
||||
unlock_buffer(bs->bh);
|
||||
ea_bdebug(bs->bh, "cloning");
|
||||
s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
|
||||
s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
|
||||
error = -ENOMEM;
|
||||
if (s->base == NULL)
|
||||
goto cleanup;
|
||||
memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
|
||||
s->first = ENTRY(header(s->base)+1);
|
||||
header(s->base)->h_refcount = cpu_to_le32(1);
|
||||
s->here = ENTRY(s->base + offset);
|
||||
|
|
|
@ -2114,7 +2114,7 @@ __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
|
|||
/**
|
||||
* jbd2_journal_try_to_free_buffers() - try to free page buffers.
|
||||
* @journal: journal for operation
|
||||
* @page: to try and free
|
||||
* @folio: Folio to detach data from.
|
||||
*
|
||||
* For all the buffers on this page,
|
||||
* if they are fully written out ordered data, move them onto BUF_CLEAN
|
||||
|
|
Loading…
Reference in a new issue