Commit graph

766 commits

Author SHA1 Message Date
Theodore Ts'o
eb7054212e ext4: update the cached overhead value in the superblock
If we (re-)calculate the file system overhead amount and it's
different from the on-disk s_overhead_clusters value, update the
on-disk version since this can take potentially quite a while on
bigalloc file systems.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2022-04-14 22:39:00 -04:00
Ye Bin
c186f0887f ext4: fix use-after-free in ext4_search_dir
We got issue as follows:
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
==================================================================
BUG: KASAN: use-after-free in ext4_search_dir fs/ext4/namei.c:1394 [inline]
BUG: KASAN: use-after-free in search_dirblock fs/ext4/namei.c:1199 [inline]
BUG: KASAN: use-after-free in __ext4_find_entry+0xdca/0x1210 fs/ext4/namei.c:1553
Read of size 1 at addr ffff8881317c3005 by task syz-executor117/2331

CPU: 1 PID: 2331 Comm: syz-executor117 Not tainted 5.10.0+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:83 [inline]
 dump_stack+0x144/0x187 lib/dump_stack.c:124
 print_address_description+0x7d/0x630 mm/kasan/report.c:387
 __kasan_report+0x132/0x190 mm/kasan/report.c:547
 kasan_report+0x47/0x60 mm/kasan/report.c:564
 ext4_search_dir fs/ext4/namei.c:1394 [inline]
 search_dirblock fs/ext4/namei.c:1199 [inline]
 __ext4_find_entry+0xdca/0x1210 fs/ext4/namei.c:1553
 ext4_lookup_entry fs/ext4/namei.c:1622 [inline]
 ext4_lookup+0xb8/0x3a0 fs/ext4/namei.c:1690
 __lookup_hash+0xc5/0x190 fs/namei.c:1451
 do_rmdir+0x19e/0x310 fs/namei.c:3760
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x445e59
Code: 4d c7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 1b c7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff2277fac8 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 0000000000400280 RCX: 0000000000445e59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200000c0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000002
R10: 00007fff2277f990 R11: 0000000000000246 R12: 0000000000000000
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:0000000048cd3304 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1317c3
flags: 0x200000000000000()
raw: 0200000000000000 ffffea0004526588 ffffea0004528088 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881317c2f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881317c2f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881317c3000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8881317c3080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881317c3100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

ext4_search_dir:
  ...
  de = (struct ext4_dir_entry_2 *)search_buf;
  dlimit = search_buf + buf_size;
  while ((char *) de < dlimit) {
  ...
    if ((char *) de + de->name_len <= dlimit &&
	 ext4_match(dir, fname, de)) {
	    ...
    }
  ...
    de_len = ext4_rec_len_from_disk(de->rec_len, dir->i_sb->s_blocksize);
    if (de_len <= 0)
      return -1;
    offset += de_len;
    de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
  }

Assume:
de=0xffff8881317c2fff
dlimit=0x0xffff8881317c3000

If read 'de->name_len' which address is 0xffff8881317c3005, obviously is
out of range, then will trigger use-after-free.
To solve this issue, 'dlimit' must reserve 8 bytes, as we will read
'de->name_len' to judge if '(char *) de + de->name_len' out of range.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220324064816.1209985-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2022-04-12 22:24:22 -04:00
Darrick J. Wong
ad5cd4f4ee ext4: fix fallocate to use file_modified to update permissions consistently
Since the initial introduction of (posix) fallocate back at the turn of
the century, it has been possible to use this syscall to change the
user-visible contents of files.  This can happen by extending the file
size during a preallocation, or through any of the newer modes (punch,
zero, collapse, insert range).  Because the call can be used to change
file contents, we should treat it like we do any other modification to a
file -- update the mtime, and drop set[ug]id privileges/capabilities.

The VFS function file_modified() does all this for us if pass it a
locked inode, so let's make fallocate drop permissions correctly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20220308185043.GA117678@magnolia
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2022-04-12 22:22:02 -04:00
Ritesh Harjani
b3998b3bc6 ext4: improve fast_commit performance and scalability
Currently ext4_fc_commit_dentry_updates() is of quadratic time
complexity, which is causing performance bottlenecks with high
threads/file/dir count with fs_mark.

This patch makes commit dentry updates (and hence ext4_fc_commit()) path
to linear time complexity. Hence improves the performance of workloads
which does fsync on multiple threads/open files one-by-one.

Absolute numbers in avg file creates per sec (from fs_mark in 1K order)
=======================================================================
no.     Order   without-patch(K)   with-patch(K)   Diff(%)
1       1        16.90              17.51           +3.60
2       2,2      32.08              31.80           -0.87
3       3,3      53.97              55.01           +1.92
4       4,4      78.94              76.90           -2.58
5       5,5      95.82              95.37           -0.46
6       6,6      87.92              103.38          +17.58
7       6,10      0.73              126.13          +17178.08
8       6,14      2.33              143.19          +6045.49

workload type
==============
For e.g. 7th row order of 6,10 (2^6 == 64 && 2^10 == 1024)
echo /run/riteshh/mnt/{1..64} |sed -E 's/[[:space:]]+/ -d /g' \
  | xargs -I {} bash -c "sudo fs_mark -L 100 -D 1024 -n 1024 -s0 -S5 -d {}"

Perf profile
(w/o patches)
=============================
87.15%  [kernel]  [k] ext4_fc_commit           --> Heavy contention/bottleneck
 1.98%  [kernel]  [k] perf_event_interrupt
 0.96%  [kernel]  [k] power_pmu_enable
 0.91%  [kernel]  [k] update_sd_lb_stats.constprop.0
 0.67%  [kernel]  [k] ktime_get

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/930f35d4fd5f83e2673c868781d9ebf15e91bf4e.1645426817.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-03-02 23:11:15 -05:00
Ritesh Harjani
6bc6c2bdf1 ext4: add ext4_sb_block_valid() refactored out of ext4_inode_block_valid()
This API will be needed at places where we don't have an inode
for e.g. while freeing blocks in ext4_group_add_blocks()

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/dd34a236543ad5ae7123eeebe0cb69e6bdd44f34.1644992610.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-02-25 21:34:56 -05:00
Ritesh Harjani
123e3016ee ext4: rename ext4_set_bits to mb_set_bits
ext4_set_bits() should actually be mb_set_bits() for uniform API naming
convention.
This is via below cmd -

grep -nr "ext4_set_bits" fs/ext4/ | cut -d ":" -f 1 | xargs sed -i 's/ext4_set_bits/mb_set_bits/g'

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/f1f6ece1405b76a7a987e9145d1adfaf71e30695.1644992610.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-02-25 21:34:56 -05:00
Linus Torvalds
d8ad2ce873 Various bug fixes for ext4 fast commit and inline data handling. Also
fix regression introduced as part of moving to the new mount API.
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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:
 "Various bug fixes for ext4 fast commit and inline data handling.

  Also fix regression introduced as part of moving to the new mount API"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  fs/ext4: fix comments mentioning i_mutex
  ext4: fix incorrect type issue during replay_del_range
  jbd2: fix kernel-doc descriptions for jbd2_journal_shrink_{scan,count}()
  ext4: fix potential NULL pointer dereference in ext4_fill_super()
  jbd2: refactor wait logic for transaction updates into a common function
  jbd2: cleanup unused functions declarations from jbd2.h
  ext4: fix error handling in ext4_fc_record_modified_inode()
  ext4: remove redundant max inline_size check in ext4_da_write_inline_data_begin()
  ext4: fix error handling in ext4_restore_inline_data()
  ext4: fast commit may miss file actions
  ext4: fast commit may not fallback for ineligible commit
  ext4: modify the logic of ext4_mb_new_blocks_simple
  ext4: prevent used blocks from being allocated during fast commit replay
2022-02-06 10:34:45 -08:00
hongnanli
f340b3d902 fs/ext4: fix comments mentioning i_mutex
inode->i_mutex has been replaced with inode->i_rwsem long ago. Fix
comments still mentioning i_mutex.

Signed-off-by: hongnanli <hongnan.li@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220121070611.21618-1-hongnan.li@linux.alibaba.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-02-03 10:57:53 -05:00
Xin Yin
bdc8a53a6f ext4: fast commit may miss file actions
in the follow scenario:
1. jbd start transaction n
2. task A get new handle for transaction n+1
3. task A do some actions and add inode to FC_Q_MAIN fc_q
4. jbd complete transaction n and clear FC_Q_MAIN fc_q
5. task A call fsync

Fast commit will lost the file actions during a full commit.

we should also add updates to staging queue during a full commit.
and in ext4_fc_cleanup(), when reset a inode's fc track range, check
it's i_sync_tid, if it bigger than current transaction tid, do not
rest it, or we will lost the track range.

And EXT4_MF_FC_COMMITTING is not needed anymore, so drop it.

Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
Link: https://lore.kernel.org/r/20220117093655.35160-3-yinxin.x@bytedance.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2022-02-03 10:57:02 -05:00
Xin Yin
e85c81ba88 ext4: fast commit may not fallback for ineligible commit
For the follow scenario:
1. jbd start commit transaction n
2. task A get new handle for transaction n+1
3. task A do some ineligible actions and mark FC_INELIGIBLE
4. jbd complete transaction n and clean FC_INELIGIBLE
5. task A call fsync

In this case fast commit will not fallback to full commit and
transaction n+1 also not handled by jbd.

Make ext4_fc_mark_ineligible() also record transaction tid for
latest ineligible case, when call ext4_fc_cleanup() check
current transaction tid, if small than latest ineligible tid
do not clear the EXT4_MF_FC_INELIGIBLE.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reported-by: Ritesh Harjani <riteshh@linux.ibm.com>
Suggested-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
Link: https://lore.kernel.org/r/20220117093655.35160-2-yinxin.x@bytedance.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2022-02-03 10:56:39 -05:00
Xin Yin
599ea31d13 ext4: prevent used blocks from being allocated during fast commit replay
During fast commit replay procedure, we clear inode blocks bitmap in
ext4_ext_clear_bb(), this may cause ext4_mb_new_blocks_simple() allocate
blocks still in use.

Make ext4_fc_record_regions() also record physical disk regions used by
inodes during replay procedure. Then ext4_mb_new_blocks_simple() can
excludes these blocks in use.

Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
Link: https://lore.kernel.org/r/20220110035141.1980-2-yinxin.x@bytedance.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2022-02-03 10:56:01 -05:00
Christoph Hellwig
5298d4bfe8 unicode: clean up the Kconfig symbol confusion
Turn the CONFIG_UNICODE symbol into a tristate that generates some always
built in code and remove the confusing CONFIG_UNICODE_UTF8_DATA symbol.

Note that a lot of the IS_ENABLED() checks could be turned from cpp
statements into normal ifs, but this change is intended to be fairly
mechanic, so that should be cleaned up later.

Fixes: 2b3d047870 ("unicode: Add utf8-data module")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
2022-01-20 19:57:24 -05:00
Linus Torvalds
3acbdbf42e dax + libnvdimm for v5.17
- Simplify the dax_operations API
   - Eliminate bdev_dax_pgoff() in favor of the filesystem maintaining
     and applying a partition offset to all its DAX iomap operations.
   - Remove wrappers and device-mapper stacked callbacks for
     ->copy_from_iter() and ->copy_to_iter() in favor of moving
     block_device relative offset responsibility to the
     dax_direct_access() caller.
   - Remove the need for an @bdev in filesystem-DAX infrastructure
   - Remove unused uio helpers copy_from_iter_flushcache() and
     copy_mc_to_iter() as only the non-check_copy_size() versions are
     used for DAX.
 - Prepare XFS for the pending (next merge window) DAX+reflink support
 - Remove deprecated DEV_DAX_PMEM_COMPAT support
 - Cleanup a straggling misuse of the GUID api
 
 Tags offered after the branch was cut:
 Reviewed-by: Mike Snitzer <snitzer@redhat.com>
 Link: https://lore.kernel.org/r/Ydb/3P+8nvjCjYfO@redhat.com
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Merge tag 'libnvdimm-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull dax and libnvdimm updates from Dan Williams:
 "The bulk of this is a rework of the dax_operations API after
  discovering the obstacles it posed to the work-in-progress DAX+reflink
  support for XFS and other copy-on-write filesystem mechanics.

  Primarily the need to plumb a block_device through the API to handle
  partition offsets was a sticking point and Christoph untangled that
  dependency in addition to other cleanups to make landing the
  DAX+reflink support easier.

  The DAX_PMEM_COMPAT option has been around for 4 years and not only
  are distributions shipping userspace that understand the current
  configuration API, but some are not even bothering to turn this option
  on anymore, so it seems a good time to remove it per the deprecation
  schedule. Recall that this was added after the device-dax subsystem
  moved from /sys/class/dax to /sys/bus/dax for its sysfs organization.
  All recent functionality depends on /sys/bus/dax.

  Some other miscellaneous cleanups and reflink prep patches are
  included as well.

  Summary:

   - Simplify the dax_operations API:

      - Eliminate bdev_dax_pgoff() in favor of the filesystem
        maintaining and applying a partition offset to all its DAX iomap
        operations.

      - Remove wrappers and device-mapper stacked callbacks for
        ->copy_from_iter() and ->copy_to_iter() in favor of moving
        block_device relative offset responsibility to the
        dax_direct_access() caller.

      - Remove the need for an @bdev in filesystem-DAX infrastructure

      - Remove unused uio helpers copy_from_iter_flushcache() and
        copy_mc_to_iter() as only the non-check_copy_size() versions are
        used for DAX.

   - Prepare XFS for the pending (next merge window) DAX+reflink support

   - Remove deprecated DEV_DAX_PMEM_COMPAT support

   - Cleanup a straggling misuse of the GUID api"

* tag 'libnvdimm-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (38 commits)
  iomap: Fix error handling in iomap_zero_iter()
  ACPI: NFIT: Import GUID before use
  dax: remove the copy_from_iter and copy_to_iter methods
  dax: remove the DAXDEV_F_SYNC flag
  dax: simplify dax_synchronous and set_dax_synchronous
  uio: remove copy_from_iter_flushcache() and copy_mc_to_iter()
  iomap: turn the byte variable in iomap_zero_iter into a ssize_t
  memremap: remove support for external pgmap refcounts
  fsdax: don't require CONFIG_BLOCK
  iomap: build the block based code conditionally
  dax: fix up some of the block device related ifdefs
  fsdax: shift partition offset handling into the file systems
  dax: return the partition offset from fs_dax_get_by_bdev
  iomap: add a IOMAP_DAX flag
  xfs: pass the mapping flags to xfs_bmbt_to_iomap
  xfs: use xfs_direct_write_iomap_ops for DAX zeroing
  xfs: move dax device handling into xfs_{alloc,free}_buftarg
  ext4: cleanup the dax handling in ext4_fill_super
  ext2: cleanup the dax handling in ext2_fill_super
  fsdax: decouple zeroing from the iomap buffered I/O code
  ...
2022-01-12 15:46:11 -08:00
xu xin
a2e3965df4 ext4: use BUG_ON instead of if condition followed by BUG
BUG_ON would be better.

This issue was detected with the help of Coccinelle.

Reported-by: Zeal robot <zealci@zte.com.cn>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Link: https://lore.kernel.org/r/20211228073252.580296-1-xu.xin16@zte.com.cn
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-01-10 13:25:56 -05:00
Lukas Czerner
2327fb2e23 ext4: change s_last_trim_minblks type to unsigned long
There is no good reason for the s_last_trim_minblks to be atomic. There is
no data integrity needed and there is no real danger in setting and
reading it in a racy manner. Change it to be unsigned long, the same type
as s_clusters_per_group which is the maximum that's allowed.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Suggested-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20211103145122.17338-1-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-01-10 13:25:55 -05:00
Lukas Czerner
bbc605cdb1 ext4: implement support for get/set fs label
Implement support for FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL ioctls for
online reading and setting of file system label.

ext4_ioctl_getlabel() is simple, just get the label from the primary
superblock. This might not be the first sb on the file system if
'sb=' mount option is used.

In ext4_ioctl_setlabel() we update what ext4 currently views as a
primary superblock and then proceed to update backup superblocks. There
are two caveats:
 - the primary superblock might not be the first superblock and so it
   might not be the one used by userspace tools if read directly
   off the disk.
 - because the primary superblock might not be the first superblock we
   potentialy have to update it as part of backup superblock update.
   However the first sb location is a bit more complicated than the rest
   so we have to account for that.

The superblock modification is created generic enough so the
infrastructure can be used for other potential superblock modification
operations, such as chaning UUID.

Tested with generic/492 with various configurations. I also checked the
behavior with 'sb=' mount options, including very large file systems
with and without sparse_super/sparse_super2.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Link: https://lore.kernel.org/r/20211213135618.43303-1-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-01-10 13:25:55 -05:00
Sebastian Andrzej Siewior
ab047d516d ext4: destroy ext4_fc_dentry_cachep kmemcache on module removal
The kmemcache for ext4_fc_dentry_cachep remains registered after module
removal.

Destroy ext4_fc_dentry_cachep kmemcache on module removal.

Fixes: aa75f4d3da ("ext4: main fast-commit commit path")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211110134640.lyku5vklvdndw6uk@linutronix.de
Link: https://lore.kernel.org/r/YbiK3JetFFl08bd7@linutronix.de
Link: https://lore.kernel.org/r/20211223164436.2628390-1-bigeasy@linutronix.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2022-01-10 13:25:54 -05:00
Harshad Shirwadkar
0915e464cb ext4: simplify updating of fast commit stats
Move fast commit stats updating logic to a separate function from
ext4_fc_commit(). This significantly improves readability of
ext4_fc_commit().

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211223202140.2061101-4-harshads@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-12-23 18:13:25 -05:00
Harshad Shirwadkar
7bbbe241ec ext4: drop ineligible txn start stop APIs
This patch drops ext4_fc_start_ineligible() and
ext4_fc_stop_ineligible() APIs. Fast commit ineligible transactions
should simply call ext4_fc_mark_ineligible() after starting the
trasaction.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211223202140.2061101-3-harshads@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-12-23 18:13:25 -05:00
Christoph Hellwig
cd913c76f4 dax: return the partition offset from fs_dax_get_by_bdev
Prepare for the removal of the block_device from the DAX I/O path by
returning the partition offset from fs_dax_get_by_bdev so that the file
systems have it at hand for use during I/O.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-26-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-12-04 08:58:54 -08:00
Xiyu Yang
31d21d219b ext4: convert from atomic_t to refcount_t on ext4_io_end->count
refcount_t type and corresponding API can protect refcounters from
accidental underflow and overflow and further use-after-free situations.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/1626674355-55795-1-git-send-email-xiyuyang19@fudan.edu.cn
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-11-04 10:33:24 -04:00
Linus Torvalds
ca3cef466f Fix a number of ext4 bugs in fast_commit, inline data, and delayed
allocation.  Also fix error handling code paths in ext4_dx_readdir()
 and ext4_fill_super().  Finally, avoid a grabbing a journal head in
 the delayed allocation write in the common cases where we are
 overwriting an pre-existing block or appending to an inode.
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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 number of ext4 bugs in fast_commit, inline data, and delayed
  allocation.

  Also fix error handling code paths in ext4_dx_readdir() and
  ext4_fill_super().

  Finally, avoid a grabbing a journal head in the delayed allocation
  write in the common cases where we are overwriting a pre-existing
  block or appending to an inode"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: recheck buffer uptodate bit under buffer lock
  ext4: fix potential infinite loop in ext4_dx_readdir()
  ext4: flush s_error_work before journal destroy in ext4_fill_super
  ext4: fix loff_t overflow in ext4_max_bitmap_size()
  ext4: fix reserved space counter leakage
  ext4: limit the number of blocks in one ADD_RANGE TLV
  ext4: enforce buffer head state assertion in ext4_da_map_blocks
  ext4: remove extent cache entries when truncating inline data
  ext4: drop unnecessary journal handle in delalloc write
  ext4: factor out write end code of inline file
  ext4: correct the error path of ext4_write_inline_data_end()
  ext4: check and update i_disksize properly
  ext4: add error checking to ext4_ext_replay_set_iblocks()
2021-10-03 13:56:53 -07:00
Theodore Ts'o
11ef08c9eb Merge branch 'delalloc-buffer-write' into dev
Fix a bug in how we update i_disksize, and the error path in
inline_data_end.  Finally, drop an unnecessary creation of a journal
handle which was only needed for inline data, which can give us a
large performance gain in delayed allocation writes.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-09-09 10:47:06 -04:00
Zhang Yi
6984aef598 ext4: factor out write end code of inline file
Now that the inline_data file write end procedure are falled into the
common write end functions, it is not clear. Factor them out and do
some cleanup. This patch also drop ext4_da_write_inline_data_end()
and switch to use ext4_write_inline_data_end() instead because we also
need to do the same error processing if we failed to write data into
inline entry.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20210716122024.1105856-4-yi.zhang@huawei.com
2021-09-04 23:38:18 -04:00
Linus Torvalds
111c1aa8ca In addition to some ext4 bug fixes and cleanups, this cycle we add the
orphan_file feature, which eliminates bottlenecks when doing a large
 number of parallel truncates and file deletions, and move the discard
 operation out of the jbd2 commit thread when using the discard mount
 option, to better support devices with slow discard operations.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "In addition to some ext4 bug fixes and cleanups, this cycle we add the
  orphan_file feature, which eliminates bottlenecks when doing a large
  number of parallel truncates and file deletions, and move the discard
  operation out of the jbd2 commit thread when using the discard mount
  option, to better support devices with slow discard operations"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (23 commits)
  ext4: make the updating inode data procedure atomic
  ext4: remove an unnecessary if statement in __ext4_get_inode_loc()
  ext4: move inode eio simulation behind io completeion
  ext4: Improve scalability of ext4 orphan file handling
  ext4: Orphan file documentation
  ext4: Speedup ext4 orphan inode handling
  ext4: Move orphan inode handling into a separate file
  ext4: Support for checksumming from journal triggers
  ext4: fix race writing to an inline_data file while its xattrs are changing
  jbd2: add sparse annotations for add_transaction_credits()
  ext4: fix sparse warnings
  ext4: Make sure quota files are not grabbed accidentally
  ext4: fix e2fsprogs checksum failure for mounted filesystem
  ext4: if zeroout fails fall back to splitting the extent node
  ext4: reduce arguments of ext4_fc_add_dentry_tlv
  ext4: flush background discard kwork when retry allocation
  ext4: get discard out of jbd2 commit kthread contex
  ext4: remove the repeated comment of ext4_trim_all_free
  ext4: add new helper interface ext4_try_to_trim_range()
  ext4: remove the 'group' parameter of ext4_trim_extent
  ...
2021-09-02 09:37:09 -07:00
Jan Kara
4a79a98c7b ext4: Improve scalability of ext4 orphan file handling
Even though the length of the critical section when adding / removing
orphaned inodes was significantly reduced by using orphan file, the
contention of lock protecting orphan file still appears high in profiles
for truncate / unlink intensive workloads with high number of threads.

This patch makes handling of orphan file completely lockless. Also to
reduce conflicts between CPUs different CPUs start searching for empty
slot in orphan file in different blocks.

Performance comparison of locked orphan file handling, lockless orphan
file handling, and completely disabled orphan inode handling
from 80 CPU Xeon Server with 526 GB of RAM, filesystem located on
SAS SSD disk, average of 5 runs:

stress-orphan (microbenchmark truncating files byte-by-byte from N
processes in parallel)

Threads Time            Time            Time
        Orphan locked   Orphan lockless No orphan
  1       0.945600       0.939400        0.891200
  2       1.331800       1.246600        1.174400
  4       1.995000       1.780600        1.713200
  8       6.424200       4.900000        4.106000
 16      14.937600       8.516400        8.138000
 32      33.038200      24.565600       24.002200
 64      60.823600      39.844600       38.440200
128     122.941400      70.950400       69.315000

So we can see that with lockless orphan file handling, addition /
deletion of orphaned inodes got almost completely out of picture even
for a microbenchmark stressing it.

For reaim creat_clo workload on ramdisk there are also noticeable gains
(average of 5 runs):

Clients         Vanilla (ops/s)        Patched (ops/s)
creat_clo-1     14705.88 (   0.00%)    14354.07 *  -2.39%*
creat_clo-3     27108.43 (   0.00%)    28301.89 (   4.40%)
creat_clo-5     37406.48 (   0.00%)    45180.73 *  20.78%*
creat_clo-7     41338.58 (   0.00%)    54687.50 *  32.29%*
creat_clo-9     45226.13 (   0.00%)    62937.07 *  39.16%*
creat_clo-11    44000.00 (   0.00%)    65088.76 *  47.93%*
creat_clo-13    36516.85 (   0.00%)    68661.97 *  88.03%*
creat_clo-15    30864.20 (   0.00%)    69551.78 * 125.35%*
creat_clo-17    27478.45 (   0.00%)    67729.08 * 146.48%*
creat_clo-19    25000.00 (   0.00%)    61621.62 * 146.49%*
creat_clo-21    18772.35 (   0.00%)    63829.79 * 240.02%*
creat_clo-23    16698.94 (   0.00%)    61938.96 * 270.92%*
creat_clo-25    14973.05 (   0.00%)    56947.61 * 280.33%*
creat_clo-27    16436.69 (   0.00%)    65008.03 * 295.51%*
creat_clo-29    13949.01 (   0.00%)    69047.62 * 395.00%*
creat_clo-31    14283.52 (   0.00%)    67982.45 * 375.95%*

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210816095713.16537-5-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-08-30 23:36:51 -04:00
Jan Kara
02f310fcf4 ext4: Speedup ext4 orphan inode handling
Ext4 orphan inode handling is a bottleneck for workloads which heavily
truncate / unlink small files since it contends on the global
s_orphan_mutex lock (and generally it's difficult to improve scalability
of the ondisk linked list of orphaned inodes).

This patch implements new way of handling orphan inodes. Instead of
linking orphaned inode into a linked list, we store it's inode number in
a new special file which we call "orphan file". Only if there's no more
space in the orphan file (too many inodes are currently orphaned) we
fall back to using old style linked list. Currently we protect
operations in the orphan file with a spinlock for simplicity but even in
this setting we can substantially reduce the length of the critical
section and thus speedup some workloads. In the next patch we improve
this by making orphan handling lockless.

Note that the change is backwards compatible when the filesystem is
clean - the existence of the orphan file is a compat feature, we set
another ro-compat feature indicating orphan file needs scanning for
orphaned inodes when mounting filesystem read-write. This ro-compat
feature gets cleared on unmount / remount read-only.

Some performance data from 80 CPU Xeon Server with 512 GB of RAM,
filesystem located on SSD, average of 5 runs:

stress-orphan (microbenchmark truncating files byte-by-byte from N
processes in parallel)

Threads Time            Time
        Vanilla         Patched
  1       1.057200        0.945600
  2       1.680400        1.331800
  4       2.547000        1.995000
  8       7.049400        6.424200
 16      14.827800       14.937600
 32      40.948200       33.038200
 64      87.787400       60.823600
128     206.504000      122.941400

So we can see significant wins all over the board.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210816095713.16537-3-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-08-30 23:36:51 -04:00
Jan Kara
25c6d98fc4 ext4: Move orphan inode handling into a separate file
Move functions for handling orphan inodes into a new file
fs/ext4/orphan.c to have them in one place and somewhat reduce size of
other files. No code changes.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210816095713.16537-2-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-08-30 23:36:51 -04:00
Jan Kara
188c299e2a ext4: Support for checksumming from journal triggers
JBD2 layer support triggers which are called when journaling layer moves
buffer to a certain state. We can use the frozen trigger, which gets
called when buffer data is frozen and about to be written out to the
journal, to compute block checksums for some buffer types (similarly as
does ocfs2). This avoids unnecessary repeated recomputation of the
checksum (at the cost of larger window where memory corruption won't be
caught by checksumming) and is even necessary when there are
unsynchronized updaters of the checksummed data.

So add superblock and journal trigger type arguments to
ext4_journal_get_write_access() and ext4_journal_get_create_access() so
that frozen triggers can be set accordingly. Also add inode argument to
ext4_walk_page_buffers() and all the callbacks used with that function
for the same purpose. This patch is mostly only a change of prototype of
the above mentioned functions and a few small helpers. Real checksumming
will come later.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210816095713.16537-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-08-30 23:36:50 -04:00
Wang Jianchao
5036ab8df2 ext4: flush background discard kwork when retry allocation
The background discard kwork tries to mark blocks used and issue
discard. This can make filesystem suffer from NOSPC error, xfstest
generic/371 can fail due to it. Fix it by flushing discard kwork
in ext4_should_retry_alloc. At the same time, give up discard at
the moment.

Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
Link: https://lore.kernel.org/r/20210830075246.12516-6-jianchao.wan9@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-08-30 23:35:53 -04:00
Wang Jianchao
55cdd0af2b ext4: get discard out of jbd2 commit kthread contex
Right now, discard is issued and waited to be completed in jbd2
commit kthread context after the logs are committed. When large
amount of files are deleted and discard is flooding, jbd2 commit
kthread can be blocked for long time. Then all of the metadata
operations can be blocked to wait the log space.

One case is the page fault path with read mm->mmap_sem held, which
wants to update the file time but has to wait for the log space.
When other threads in the task wants to do mmap, then write mmap_sem
is blocked. Finally all of the following read mmap_sem requirements
are blocked, even the ps command which need to read the /proc/pid/
-cmdline. Our monitor service which needs to read /proc/pid/cmdline
used to be blocked for 5 mins.

This patch frees the blocks back to buddy after commit and then do
discard in a async kworker context in fstrim fashion, namely,
 - mark blocks to be discarded as used if they have not been allocated
 - do discard
 - mark them free
After this, jbd2 commit kthread won't be blocked any more by discard
and we won't get NOSPC even if the discard is slow or throttled.

Link: https://marc.info/?l=linux-kernel&m=162143690731901&w=2
Suggested-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
Link: https://lore.kernel.org/r/20210830075246.12516-5-jianchao.wan9@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-08-30 23:34:52 -04:00
Jan Kara
d4f5258eae ext4: Convert to use mapping->invalidate_lock
Convert ext4 to use mapping->invalidate_lock instead of its private
EXT4_I(inode)->i_mmap_sem. This is mostly search-and-replace. By this
conversion we fix a long standing race between hole punching and read(2)
/ readahead(2) paths that can lead to stale page cache contents.

CC: <linux-ext4@vger.kernel.org>
CC: Ted Tso <tytso@mit.edu>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
2021-07-13 14:29:00 +02:00
Jonathan Davies
d578b99443 ext4: notify sysfs on errors_count value change
After s_error_count is incremented, signal the change in the
corresponding sysfs attribute via sysfs_notify. This allows userspace to
poll() on changes to /sys/fs/ext4/*/errors_count.

[ Moved call of ext4_notify_error_sysfs() to flush_stashed_error_work()
  to avoid BUG's caused by calling sysfs_notify trying to sleep after
  being called from an invalid context. -- TYT ]

Signed-off-by: Jonathan Davies <jonathan.davies@nutanix.com>
Link: https://lore.kernel.org/r/20210611140209.28903-1-jonathan.davies@nutanix.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-06-29 21:06:02 -04:00
Eric Biggers
6d2424a845 ext4: fix comment for s_hash_unsigned
Fix the comment for s_hash_unsigned to not be the opposite of what it
actually is.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20210527235557.2377525-1-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-06-24 09:42:41 -04:00
Leah Rumancik
351a0a3fbc ext4: add ioctl EXT4_IOC_CHECKPOINT
ioctl EXT4_IOC_CHECKPOINT checkpoints and flushes the journal. This
includes forcing all the transactions to the log, checkpointing the
transactions, and flushing the log to disk. This ioctl takes u32 "flags"
as an argument. Three flags are supported. EXT4_IOC_CHECKPOINT_FLAG_DRY_RUN
can be used to verify input to the ioctl. It returns error if there is any
invalid input, otherwise it returns success without performing
any checkpointing. The other two flags, EXT4_IOC_CHECKPOINT_FLAG_DISCARD
and EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT, can be used to issue requests to
discard or zeroout the journal logs blocks, respectively. At this
point, EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT is primarily added to enable
testing of this codepath on devices that don't support discard.
EXT4_IOC_CHECKPOINT_FLAG_DISCARD and EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT
cannot both be set.

Systems that wish to achieve content deletion SLO can set up a daemon
that calls this ioctl at a regular interval such that it matches with the
SLO requirement. Thus, with this patch, the ext4_dir_entry2 wipeout
patch[1], and the Ext4 "-o discard" mount option set, Ext4 can now
guarantee that all file contents, file metatdata, and filenames will not
be accessible through the filesystem and will have had discard or
zeroout requests issued for corresponding device blocks.

The __jbd2_journal_erase function could also be used to discard or
zero-fill the journal during journal load after recovery. This would
provide a potential solution to a journal replay bug reported earlier this
year[2]. After a successful journal recovery, e2fsck can call this ioctl to
discard the journal as well.

[1] https://lore.kernel.org/linux-ext4/YIHknqxngB1sUdie@mit.edu/
[2] https://lore.kernel.org/linux-ext4/YDZoaacIYStFQT8g@mit.edu/

Link: https://lore.kernel.org/r/20210518151327.130198-2-leah.rumancik@gmail.com
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-06-22 21:34:08 -04:00
Pavel Skripkin
618f003199 ext4: fix memory leak in ext4_fill_super
static int kthread(void *_create) will return -ENOMEM
or -EINTR in case of internal failure or
kthread_stop() call happens before threadfn call.

To prevent fancy error checking and make code
more straightforward we moved all cleanup code out
of kmmpd threadfn.

Also, dropped struct mmpd_data at all. Now struct super_block
is a threadfn data and struct buffer_head embedded into
struct ext4_sb_info.

Reported-by: syzbot+d9e482e303930fa4f6ff@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Link: https://lore.kernel.org/r/20210430185046.15742-1-paskripkin@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-06-17 10:53:19 -04:00
Joseph Qi
5c680150d7 ext4: remove redundant check buffer_uptodate()
Now set_buffer_uptodate() will test first and then set, so we don't have
to check buffer_uptodate() first, remove it to simplify code.

Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Link: https://lore.kernel.org/r/1619418587-5580-1-git-send-email-joseph.qi@linux.alibaba.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-06-17 10:53:19 -04:00
Linus Torvalds
9f67672a81 New features for ext4 this cycle include support for encrypted
casefold, ensure that deleted file names are cleared in directory
 blocks by zeroing directory entries when they are unlinked or moved as
 part of a hash tree node split.  We also improve the block allocator's
 performance on a freshly mounted file system by prefetching block
 bitmaps.
 
 There are also the usual cleanups and bug fixes, including fixing a
 page cache invalidation race when there is mixed buffered and direct
 I/O and the block size is less than page size, and allow the dax flag
 to be set and cleared on inline directories.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "New features for ext4 this cycle include support for encrypted
  casefold, ensure that deleted file names are cleared in directory
  blocks by zeroing directory entries when they are unlinked or moved as
  part of a hash tree node split. We also improve the block allocator's
  performance on a freshly mounted file system by prefetching block
  bitmaps.

  There are also the usual cleanups and bug fixes, including fixing a
  page cache invalidation race when there is mixed buffered and direct
  I/O and the block size is less than page size, and allow the dax flag
  to be set and cleared on inline directories"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (32 commits)
  ext4: wipe ext4_dir_entry2 upon file deletion
  ext4: Fix occasional generic/418 failure
  fs: fix reporting supported extra file attributes for statx()
  ext4: allow the dax flag to be set and cleared on inline directories
  ext4: fix debug format string warning
  ext4: fix trailing whitespace
  ext4: fix various seppling typos
  ext4: fix error return code in ext4_fc_perform_commit()
  ext4: annotate data race in jbd2_journal_dirty_metadata()
  ext4: annotate data race in start_this_handle()
  ext4: fix ext4_error_err save negative errno into superblock
  ext4: fix error code in ext4_commit_super
  ext4: always panic when errors=panic is specified
  ext4: delete redundant uptodate check for buffer
  ext4: do not set SB_ACTIVE in ext4_orphan_cleanup()
  ext4: make prefetch_block_bitmaps default
  ext4: add proc files to monitor new structures
  ext4: improve cr 0 / cr 1 group scanning
  ext4: add MB_NUM_ORDERS macro
  ext4: add mballoc stats proc file
  ...
2021-04-30 15:35:30 -07:00
Miklos Szeredi
4db5c2e623 ext4: convert to fileattr
Use the fileattr API to let the VFS handle locking, permission checking and
conversion.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
2021-04-12 15:04:29 +02:00
Harshad Shirwadkar
21175ca434 ext4: make prefetch_block_bitmaps default
Block bitmap prefetching is needed for these allocator optimization
data structures to get populated and provide better group scanning
order. So, turn it on bu default. prefetch_block_bitmaps mount option
is now marked as removed and a new option no_prefetch_block_bitmaps is
added to disable block bitmap prefetching.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20210401172129.189766-8-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-04-09 11:34:59 -04:00
Harshad Shirwadkar
f68f406385 ext4: add proc files to monitor new structures
This patch adds a new file "mb_structs_summary" which allows us to see
the summary of the new allocator structures added in this
series. Here's the sample output of file:

optimize_scan: 1
max_free_order_lists:
        list_order_0_groups: 0
        list_order_1_groups: 0
        list_order_2_groups: 0
        list_order_3_groups: 0
        list_order_4_groups: 0
        list_order_5_groups: 0
        list_order_6_groups: 0
        list_order_7_groups: 0
        list_order_8_groups: 0
        list_order_9_groups: 0
        list_order_10_groups: 0
        list_order_11_groups: 0
        list_order_12_groups: 0
        list_order_13_groups: 40
fragment_size_tree:
        tree_min: 16384
        tree_max: 32768
        tree_nodes: 40

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20210401172129.189766-7-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-04-09 11:34:59 -04:00
Harshad Shirwadkar
196e402adf ext4: improve cr 0 / cr 1 group scanning
Instead of traversing through groups linearly, scan groups in specific
orders at cr 0 and cr 1. At cr 0, we want to find groups that have the
largest free order >= the order of the request. So, with this patch,
we maintain lists for each possible order and insert each group into a
list based on the largest free order in its buddy bitmap. During cr 0
allocation, we traverse these lists in the increasing order of largest
free orders. This allows us to find a group with the best available cr
0 match in constant time. If nothing can be found, we fallback to cr 1
immediately.

At CR1, the story is slightly different. We want to traverse in the
order of increasing average fragment size. For CR1, we maintain a rb
tree of groupinfos which is sorted by average fragment size. Instead
of traversing linearly, at CR1, we traverse in the order of increasing
average fragment size, starting at the most optimal group. This brings
down cr 1 search complexity to log(num groups).

For cr >= 2, we just perform the linear search as before. Also, in
case of lock contention, we intermittently fallback to linear search
even in CR 0 and CR 1 cases. This allows us to proceed during the
allocation path even in case of high contention.

There is an opportunity to do optimization at CR2 too. That's because
at CR2 we only consider groups where bb_free counter (number of free
blocks) is greater than the request extent size. That's left as future
work.

All the changes introduced in this patch are protected under a new
mount option "mb_optimize_scan".

With this patchset, following experiment was performed:

Created a highly fragmented disk of size 65TB. The disk had no
contiguous 2M regions. Following command was run consecutively for 3
times:

time dd if=/dev/urandom of=file bs=2M count=10

Here are the results with and without cr 0/1 optimizations introduced
in this patch:

|---------+------------------------------+---------------------------|
|         | Without CR 0/1 Optimizations | With CR 0/1 Optimizations |
|---------+------------------------------+---------------------------|
| 1st run | 5m1.871s                     | 2m47.642s                 |
| 2nd run | 2m28.390s                    | 0m0.611s                  |
| 3rd run | 2m26.530s                    | 0m1.255s                  |
|---------+------------------------------+---------------------------|

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20210401172129.189766-6-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-04-09 11:34:59 -04:00
Harshad Shirwadkar
a6c75eaf11 ext4: add mballoc stats proc file
Add new stats for measuring the performance of mballoc. This patch is
forked from Artem Blagodarenko's work that can be found here:

https://github.com/lustre/lustre-release/blob/master/ldiskfs/kernel_patches/patches/rhel8/ext4-simple-blockalloc.patch

This patch reorganizes the stats by cr level. This is how the output
looks like:

mballoc:
	reqs: 0
	success: 0
	groups_scanned: 0
	cr0_stats:
		hits: 0
		groups_considered: 0
		useless_loops: 0
		bad_suggestions: 0
	cr1_stats:
		hits: 0
		groups_considered: 0
		useless_loops: 0
		bad_suggestions: 0
	cr2_stats:
		hits: 0
		groups_considered: 0
		useless_loops: 0
	cr3_stats:
		hits: 0
		groups_considered: 0
		useless_loops: 0
	extents_scanned: 0
		goal_hits: 0
		2^n_hits: 0
		breaks: 0
		lost: 0
	buddies_generated: 0/40
	buddies_time_used: 0
	preallocated: 0
	discarded: 0

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20210401172129.189766-4-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-04-09 11:34:59 -04:00
Harshad Shirwadkar
67d2518604 ext4: drop s_mb_bal_lock and convert protected fields to atomic
s_mb_buddies_generated gets used later in this patch series to
determine if the cr 0 and cr 1 optimziations should be performed or
not. Currently, s_mb_buddies_generated is protected under a
spin_lock. In the allocation path, it is better if we don't depend on
the lock and instead read the value atomically. In order to do that,
we drop s_bal_lock altogether and we convert the only two protected
fields by it s_mb_buddies_generated and s_mb_generation_time to atomic
type.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20210401172129.189766-2-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-04-09 11:34:58 -04:00
Daniel Rosenberg
1ae98e295f ext4: optimize match for casefolded encrypted dirs
Matching names with casefolded encrypting directories requires
decrypting entries to confirm case since we are case preserving. We can
avoid needing to decrypt if our hash values don't match.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Link: https://lore.kernel.org/r/20210319073414.1381041-3-drosen@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-04-05 22:18:36 -04:00
Daniel Rosenberg
471fbbea7f ext4: handle casefolding with encryption
This adds support for encryption with casefolding.

Since the name on disk is case preserving, and also encrypted, we can no
longer just recompute the hash on the fly. Additionally, to avoid
leaking extra information from the hash of the unencrypted name, we use
siphash via an fscrypt v2 policy.

The hash is stored at the end of the directory entry for all entries
inside of an encrypted and casefolded directory apart from those that
deal with '.' and '..'. This way, the change is backwards compatible
with existing ext4 filesystems.

[ Changed to advertise this feature via the file:
  /sys/fs/ext4/features/encrypted_casefold -- TYT ]

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20210319073414.1381041-2-drosen@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-04-05 22:04:20 -04:00
Harshad Shirwadkar
8210bb29c1 ext4: fix rename whiteout with fast commit
This patch adds rename whiteout support in fast commits. Note that the
whiteout object that gets created is actually char device. Which
imples, the function ext4_inode_journal_mode(struct inode *inode)
would return "JOURNAL_DATA" for this inode. This has a consequence in
fast commit code that it will make creation of the whiteout object a
fast-commit ineligible behavior and thus will fall back to full
commits. With this patch, this can be observed by running fast commits
with rename whiteout and seeing the stats generated by ext4_fc_stats
tracepoint as follows:

ext4_fc_stats: dev 254:32 fc ineligible reasons:
XATTR:0, CROSS_RENAME:0, JOURNAL_FLAG_CHANGE:0, NO_MEM:0, SWAP_BOOT:0,
RESIZE:0, RENAME_DIR:0, FALLOC_RANGE:0, INODE_JOURNAL_DATA:16;
num_commits:6, ineligible: 6, numblks: 3

So in short, this patch guarantees that in case of rename whiteout, we
fall back to full commits.

Amir mentioned that instead of creating a new whiteout object for
every rename, we can create a static whiteout object with irrelevant
nlink. That will make fast commits to not fall back to full
commit. But until this happens, this patch will ensure correctness by
falling back to full commits.

Fixes: 8016e29f43 ("ext4: fast commit recovery path")
Cc: stable@kernel.org
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20210316221921.1124955-1-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-03-21 00:38:18 -04:00
Eric Whitney
efc6134527 ext4: shrink race window in ext4_should_retry_alloc()
When generic/371 is run on kvm-xfstests using 5.10 and 5.11 kernels, it
fails at significant rates on the two test scenarios that disable
delayed allocation (ext3conv and data_journal) and force actual block
allocation for the fallocate and pwrite functions in the test.  The
failure rate on 5.10 for both ext3conv and data_journal on one test
system typically runs about 85%.  On 5.11, the failure rate on ext3conv
sometimes drops to as low as 1% while the rate on data_journal
increases to nearly 100%.

The observed failures are largely due to ext4_should_retry_alloc()
cutting off block allocation retries when s_mb_free_pending (used to
indicate that a transaction in progress will free blocks) is 0.
However, free space is usually available when this occurs during runs
of generic/371.  It appears that a thread attempting to allocate
blocks is just missing transaction commits in other threads that
increase the free cluster count and reset s_mb_free_pending while
the allocating thread isn't running.  Explicitly testing for free space
availability avoids this race.

The current code uses a post-increment operator in the conditional
expression that determines whether the retry limit has been exceeded.
This means that the conditional expression uses the value of the
retry counter before it's increased, resulting in an extra retry cycle.
The current code actually retries twice before hitting its retry limit
rather than once.

Increasing the retry limit to 3 from the current actual maximum retry
count of 2 in combination with the change described above reduces the
observed failure rate to less that 0.1% on both ext3conv and
data_journal with what should be limited impact on users sensitive to
the overhead caused by retries.

A per filesystem percpu counter exported via sysfs is added to allow
users or developers to track the number of times the retry limit is
exceeded without resorting to debugging methods.  This should provide
some insight into worst case retry behavior.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Link: https://lore.kernel.org/r/20210218151132.19678-1-enwlinux@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-03-06 11:56:10 -05:00
Christian Brauner
14f3db5542
ext4: support idmapped mounts
Enable idmapped mounts for ext4. All dedicated helpers we need for this
exist. So this basically just means we're passing down the
user_namespace argument from the VFS methods to the relevant helpers.

Let's create simple example where we idmap an ext4 filesystem:

 root@f2-vm:~# truncate -s 5G ext4.img

 root@f2-vm:~# mkfs.ext4 ./ext4.img
 mke2fs 1.45.5 (07-Jan-2020)
 Discarding device blocks: done
 Creating filesystem with 1310720 4k blocks and 327680 inodes
 Filesystem UUID: 3fd91794-c6ca-4b0f-9964-289a000919cf
 Superblock backups stored on blocks:
         32768, 98304, 163840, 229376, 294912, 819200, 884736

 Allocating group tables: done
 Writing inode tables: done
 Creating journal (16384 blocks): done
 Writing superblocks and filesystem accounting information: done

 root@f2-vm:~# losetup -f --show ./ext4.img
 /dev/loop0

 root@f2-vm:~# mount /dev/loop0 /mnt

 root@f2-vm:~# ls -al /mnt/
 total 24
 drwxr-xr-x  3 root root  4096 Oct 28 13:34 .
 drwxr-xr-x 30 root root  4096 Oct 28 13:22 ..
 drwx------  2 root root 16384 Oct 28 13:34 lost+found

 # Let's create an idmapped mount at /idmapped1 where we map uid and gid
 # 0 to uid and gid 1000
 root@f2-vm:/# ./mount-idmapped --map-mount b:0:1000:1 /mnt/ /idmapped1/

 root@f2-vm:/# ls -al /idmapped1/
 total 24
 drwxr-xr-x  3 ubuntu ubuntu  4096 Oct 28 13:34 .
 drwxr-xr-x 30 root   root    4096 Oct 28 13:22 ..
 drwx------  2 ubuntu ubuntu 16384 Oct 28 13:34 lost+found

 # Let's create an idmapped mount at /idmapped2 where we map uid and gid
 # 0 to uid and gid 2000
 root@f2-vm:/# ./mount-idmapped --map-mount b:0:2000:1 /mnt/ /idmapped2/

 root@f2-vm:/# ls -al /idmapped2/
 total 24
 drwxr-xr-x  3 2000 2000  4096 Oct 28 13:34 .
 drwxr-xr-x 31 root root  4096 Oct 28 13:39 ..
 drwx------  2 2000 2000 16384 Oct 28 13:34 lost+found

Let's create another example where we idmap the rootfs filesystem
without a mapping for uid 0 and gid 0:

 # Create an idmapped mount of for a full POSIX range of rootfs under
 # /mnt but without a mapping for uid 0 to reduce attack surface

 root@f2-vm:/# ./mount-idmapped --map-mount b:1:1:65536 / /mnt/

 # Since we don't have a mapping for uid and gid 0 all files owned by
 # uid and gid 0 should show up as uid and gid 65534:
 root@f2-vm:/# ls -al /mnt/
 total 664
 drwxr-xr-x 31 nobody nogroup   4096 Oct 28 13:39 .
 drwxr-xr-x 31 root   root      4096 Oct 28 13:39 ..
 lrwxrwxrwx  1 nobody nogroup      7 Aug 25 07:44 bin -> usr/bin
 drwxr-xr-x  4 nobody nogroup   4096 Oct 28 13:17 boot
 drwxr-xr-x  2 nobody nogroup   4096 Aug 25 07:48 dev
 drwxr-xr-x 81 nobody nogroup   4096 Oct 28 04:00 etc
 drwxr-xr-x  4 nobody nogroup   4096 Oct 28 04:00 home
 lrwxrwxrwx  1 nobody nogroup      7 Aug 25 07:44 lib -> usr/lib
 lrwxrwxrwx  1 nobody nogroup      9 Aug 25 07:44 lib32 -> usr/lib32
 lrwxrwxrwx  1 nobody nogroup      9 Aug 25 07:44 lib64 -> usr/lib64
 lrwxrwxrwx  1 nobody nogroup     10 Aug 25 07:44 libx32 -> usr/libx32
 drwx------  2 nobody nogroup  16384 Aug 25 07:47 lost+found
 drwxr-xr-x  2 nobody nogroup   4096 Aug 25 07:44 media
 drwxr-xr-x 31 nobody nogroup   4096 Oct 28 13:39 mnt
 drwxr-xr-x  2 nobody nogroup   4096 Aug 25 07:44 opt
 drwxr-xr-x  2 nobody nogroup   4096 Apr 15  2020 proc
 drwx--x--x  6 nobody nogroup   4096 Oct 28 13:34 root
 drwxr-xr-x  2 nobody nogroup   4096 Aug 25 07:46 run
 lrwxrwxrwx  1 nobody nogroup      8 Aug 25 07:44 sbin -> usr/sbin
 drwxr-xr-x  2 nobody nogroup   4096 Aug 25 07:44 srv
 drwxr-xr-x  2 nobody nogroup   4096 Apr 15  2020 sys
 drwxrwxrwt 10 nobody nogroup   4096 Oct 28 13:19 tmp
 drwxr-xr-x 14 nobody nogroup   4096 Oct 20 13:00 usr
 drwxr-xr-x 12 nobody nogroup   4096 Aug 25 07:45 var

 # Since we do have a mapping for uid and gid 1000 all files owned by
 # uid and gid 1000 should simply show up as uid and gid 1000:
 root@f2-vm:/# ls -al /mnt/home/ubuntu/
 total 40
 drwxr-xr-x 3 ubuntu ubuntu  4096 Oct 28 00:43 .
 drwxr-xr-x 4 nobody nogroup 4096 Oct 28 04:00 ..
 -rw------- 1 ubuntu ubuntu  2936 Oct 28 12:26 .bash_history
 -rw-r--r-- 1 ubuntu ubuntu   220 Feb 25  2020 .bash_logout
 -rw-r--r-- 1 ubuntu ubuntu  3771 Feb 25  2020 .bashrc
 -rw-r--r-- 1 ubuntu ubuntu   807 Feb 25  2020 .profile
 -rw-r--r-- 1 ubuntu ubuntu     0 Oct 16 16:11 .sudo_as_admin_successful
 -rw------- 1 ubuntu ubuntu  1144 Oct 28 00:43 .viminfo

Link: https://lore.kernel.org/r/20210121131959.646623-39-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-ext4@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:43:46 +01:00
Christian Brauner
549c729771
fs: make helpers idmap mount aware
Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:20 +01:00