In this round, we added a new mount option, "checkpoint_merge", which introduces
a kernel thread dealing with the f2fs checkpoints. Once we start to manage the
IO priority along with blk-cgroup, the checkpoint operation can be processed in
a lower priority under the process context. Since the checkpoint holds all the
filesystem operations, we give a higher priority to the checkpoint thread all
the time.
Enhancement:
- introduce gc_merge mount option to introduce a checkpoint thread
- improve to run discard thread efficiently
- allow modular compression algorithms
- expose # of overprivision segments to sysfs
- expose runtime compression stat to sysfs
Bug fix:
- fix OOB memory access by the node id lookup
- avoid touching checkpointed data in the checkpoint-disabled mode
- fix the resizing flow to avoid kernel panic and race conditions
- fix block allocation issues on pinned files
- address some swapfile issues
- fix hugtask problem and kernel panic during atomic write operations
- don't start checkpoint thread in RO
And, we've cleaned up some kernel coding style and build warnings. In addition,
we fixed some minor race conditions and error handling routines.
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Merge tag 'f2fs-for-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"In this round, we added a new mount option, "checkpoint_merge", which
introduces a kernel thread dealing with the f2fs checkpoints. Once we
start to manage the IO priority along with blk-cgroup, the checkpoint
operation can be processed in a lower priority under the process
context. Since the checkpoint holds all the filesystem operations, we
give a higher priority to the checkpoint thread all the time.
Enhancements:
- introduce gc_merge mount option to introduce a checkpoint thread
- improve to run discard thread efficiently
- allow modular compression algorithms
- expose # of overprivision segments to sysfs
- expose runtime compression stat to sysfs
Bug fixes:
- fix OOB memory access by the node id lookup
- avoid touching checkpointed data in the checkpoint-disabled mode
- fix the resizing flow to avoid kernel panic and race conditions
- fix block allocation issues on pinned files
- address some swapfile issues
- fix hugtask problem and kernel panic during atomic write operations
- don't start checkpoint thread in RO
And, we've cleaned up some kernel coding style and build warnings. In
addition, we fixed some minor race conditions and error handling
routines"
* tag 'f2fs-for-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (48 commits)
f2fs: drop inplace IO if fs status is abnormal
f2fs: compress: remove unneed check condition
f2fs: clean up left deprecated IO trace codes
f2fs: avoid using native allocate_segment_by_default()
f2fs: remove unnecessary struct declaration
f2fs: fix to avoid NULL pointer dereference
f2fs: avoid duplicated codes for cleanup
f2fs: document: add description about compressed space handling
f2fs: clean up build warnings
f2fs: fix the periodic wakeups of discard thread
f2fs: fix to avoid accessing invalid fio in f2fs_allocate_data_block()
f2fs: fix to avoid GC/mmap race with f2fs_truncate()
f2fs: set checkpoint_merge by default
f2fs: Fix a hungtask problem in atomic write
f2fs: fix to restrict mount condition on readonly block device
f2fs: introduce gc_merge mount option
f2fs: fix to cover __allocate_new_section() with curseg_lock
f2fs: fix wrong alloc_type in f2fs_do_replace_block
f2fs: delete empty compress.h
f2fs: fix a typo in inode.c
...
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
...
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Merge tag 'ovl-update-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs update from Miklos Szeredi:
- Fix a regression introduced in 5.2 that resulted in valid overlayfs
mounts being rejected with ELOOP (Too many levels of symbolic links)
- Fix bugs found by various tools
- Miscellaneous improvements and cleanups
* tag 'ovl-update-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
ovl: add debug print to ovl_do_getxattr()
ovl: invalidate readdir cache on changes to dir with origin
ovl: allow upperdir inside lowerdir
ovl: show "userxattr" in the mount data
ovl: trivial typo fixes in the file inode.c
ovl: fix misspellings using codespell tool
ovl: do not copy attr several times
ovl: remove ovl_map_dev_ino() return value
ovl: fix error for ovl_fill_super()
ovl: fix missing revert_creds() on error path
ovl: fix leaked dentry
ovl: restrict lower null uuid for "xino=auto"
ovl: check that upperdir path is not on a read-only mount
ovl: plumb through flush method
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Merge tag 'netfs-lib-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull network filesystem helper library updates from David Howells:
"Here's a set of patches for 5.13 to begin the process of overhauling
the local caching API for network filesystems. This set consists of
two parts:
(1) Add a helper library to handle the new VM readahead interface.
This is intended to be used unconditionally by the filesystem
(whether or not caching is enabled) and provides a common
framework for doing caching, transparent huge pages and, in the
future, possibly fscrypt and read bandwidth maximisation. It also
allows the netfs and the cache to align, expand and slice up a
read request from the VM in various ways; the netfs need only
provide a function to read a stretch of data to the pagecache and
the helper takes care of the rest.
(2) Add an alternative fscache/cachfiles I/O API that uses the kiocb
facility to do async DIO to transfer data to/from the netfs's
pages, rather than using readpage with wait queue snooping on one
side and vfs_write() on the other. It also uses less memory, since
it doesn't do buffered I/O on the backing file.
Note that this uses SEEK_HOLE/SEEK_DATA to locate the data
available to be read from the cache. Whilst this is an improvement
from the bmap interface, it still has a problem with regard to a
modern extent-based filesystem inserting or removing bridging
blocks of zeros. Fixing that requires a much greater overhaul.
This is a step towards overhauling the fscache API. The change is
opt-in on the part of the network filesystem. A netfs should not try
to mix the old and the new API because of conflicting ways of handling
pages and the PG_fscache page flag and because it would be mixing DIO
with buffered I/O. Further, the helper library can't be used with the
old API.
This does not change any of the fscache cookie handling APIs or the
way invalidation is done at this time.
In the near term, I intend to deprecate and remove the old I/O API
(fscache_allocate_page{,s}(), fscache_read_or_alloc_page{,s}(),
fscache_write_page() and fscache_uncache_page()) and eventually
replace most of fscache/cachefiles with something simpler and easier
to follow.
This patchset contains the following parts:
- Some helper patches, including provision of an ITER_XARRAY iov
iterator and a function to do readahead expansion.
- Patches to add the netfs helper library.
- A patch to add the fscache/cachefiles kiocb API.
- A pair of patches to fix some review issues in the ITER_XARRAY and
read helpers as spotted by Al and Willy.
Jeff Layton has patches to add support in Ceph for this that he
intends for this merge window. I have a set of patches to support AFS
that I will post a separate pull request for.
With this, AFS without a cache passes all expected xfstests; with a
cache, there's an extra failure, but that's also there before these
patches. Fixing that probably requires a greater overhaul. Ceph also
passes the expected tests.
I also have patches in a separate branch to tidy up the handling of
PG_fscache/PG_private_2 and their contribution to page refcounting in
the core kernel here, but I haven't included them in this set and will
route them separately"
Link: https://lore.kernel.org/lkml/3779937.1619478404@warthog.procyon.org.uk/
* tag 'netfs-lib-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
netfs: Miscellaneous fixes
iov_iter: Four fixes for ITER_XARRAY
fscache, cachefiles: Add alternate API to use kiocb for read/write to cache
netfs: Add a tracepoint to log failures that would be otherwise unseen
netfs: Define an interface to talk to a cache
netfs: Add write_begin helper
netfs: Gather stats
netfs: Add tracepoints
netfs: Provide readahead and readpage netfs helpers
netfs, mm: Add set/end/wait_on_page_fscache() aliases
netfs, mm: Move PG_fscache helper funcs to linux/netfs.h
netfs: Documentation for helper library
netfs: Make a netfs helper module
mm: Implement readahead_control pageset expansion
mm/readahead: Handle ractl nr_pages being modified
fs: Document file_ra_state
mm/filemap: Pass the file_ra_state in the ractl
mm: Add set/end/wait functions for PG_private_2
iov_iter: Add ITER_XARRAY
Pull fileattr conversion updates from Miklos Szeredi via Al Viro:
"This splits the handling of FS_IOC_[GS]ETFLAGS from ->ioctl() into a
separate method.
The interface is reasonably uniform across the filesystems that
support it and gives nice boilerplate removal"
* 'miklos.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (23 commits)
ovl: remove unneeded ioctls
fuse: convert to fileattr
fuse: add internal open/release helpers
fuse: unsigned open flags
fuse: move ioctl to separate source file
vfs: remove unused ioctl helpers
ubifs: convert to fileattr
reiserfs: convert to fileattr
ocfs2: convert to fileattr
nilfs2: convert to fileattr
jfs: convert to fileattr
hfsplus: convert to fileattr
efivars: convert to fileattr
xfs: convert to fileattr
orangefs: convert to fileattr
gfs2: convert to fileattr
f2fs: convert to fileattr
ext4: convert to fileattr
ext2: convert to fileattr
btrfs: convert to fileattr
...
User or developer may still be confused about why f2fs doesn't expose
compressed space to userspace, add description about compressed space
handling policy into f2fs documentation.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
There's a substantial amount of boilerplate in filesystems handling
FS_IOC_[GS]ETFLAGS/ FS_IOC_FS[GS]ETXATTR ioctls.
Also due to userspace buffers being involved in the ioctl API this is
difficult to stack, as shown by overlayfs issues related to these ioctls.
Introduce a new internal API named "fileattr" (fsxattr can be confused with
xattr, xflags is inappropriate, since this is more than just flags).
There's significant overlap between flags and xflags and this API handles
the conversions automatically, so filesystems may choose which one to use.
In ->fileattr_get() a hint is provided to the filesystem whether flags or
xattr are being requested by userspace, but in this series this hint is
ignored by all filesystems, since generating all the attributes is cheap.
If a filesystem doesn't implemement the fileattr API, just fall back to
f_op->ioctl(). When all filesystems are converted, the fallback can be
removed.
32bit compat ioctls are now handled by the generic code as well.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Commit a888db3101 ("ovl: fix regression with re-formatted lower
squashfs") attempted to fix a regression with existing setups that
use a practice that we are trying to discourage.
The discourage part was described this way in the commit message:
"To avoid the reported regression while still allowing the new features
with single lower squashfs, do not allow decoding origin with lower null
uuid unless user opted-in to one of the new features that require
following the lower inode of non-dir upper (index, xino, metacopy)."
The three mentioned features are disabled by default in Kconfig, so
it was assumed that if they are enabled, the user opted-in for them.
Apparently, distros started to configure CONFIG_OVERLAY_FS_XINO_AUTO=y
some time ago, so users upgrading their kernels can still be affected
by said regression even though they never opted-in for any new feature.
To fix this, treat "xino=on" as "user opted-in", but not "xino=auto".
Since we are changing the behavior of "xino=auto" to no longer follow
to lower origin with null uuid, take this one step further and disable
xino in that corner case. To be consistent, disable xino also in cases
of lower fs without file handle support and upper fs without xattr
support.
Update documentation w.r.t the new "xino=auto" behavior and fix the out
dated bits of documentation regarding "xino" and regarding offline
modifications to lower layers.
Link: https://lore.kernel.org/linux-unionfs/b36a429d7c563730c28d763d4d57a6fc30508a4f.1615216996.git.kevin@kevinlocke.name/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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>
In this patch, we will add two new mount options: "gc_merge" and
"nogc_merge", when background_gc is on, "gc_merge" option can be
set to let background GC thread to handle foreground GC requests,
it can eliminate the sluggish issue caused by slow foreground GC
operation when GC is triggered from a process with limited I/O
and CPU resources.
Original idea is from Xiang.
Signed-off-by: Gao Xiang <xiang@kernel.org>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
We've missed a few documentation when adding new VM_* flags. Add the missing
pieces so they'll be in sync now.
Signed-off-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20210302000646.432358-1-peterx@redhat.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add fs/eventpoll.c to the filesystem api-summary book.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/20210210042526.23174-2-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Pull misc vfs updates from Al Viro:
"Assorted stuff pile - no common topic here"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
whack-a-mole: don't open-code iminor/imajor
9p: fix misuse of sscanf() in v9fs_stat2inode()
audit_alloc_mark(): don't open-code ERR_CAST()
fs/inode.c: make inode_init_always() initialize i_ino to 0
vfs: don't unnecessarily clone write access for writable fds
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Merge tag 'docs-5.12-2' of git://git.lwn.net/linux
Pull documentation fixes from Jonathan Corbet:
"A handful of late-arriving documentation fixes, nothing all that
notable"
* tag 'docs-5.12-2' of git://git.lwn.net/linux:
docs: proc.rst: fix indentation warning
Documentation: cgroup-v2: fix path to example BPF program
docs: powerpc: Fix tables in syscall64-abi.rst
Documentation: features: refresh feature list
Documentation: features: remove c6x references
docs: ABI: testing: ima_policy: Fixed missing bracket
Fix unaesthetic indentation
scripts: kernel-doc: fix array element capture in pointer-to-func parsing
doc: use KCFLAGS instead of EXTRA_CFLAGS to pass flags from command line
Documentation: proc.rst: add more about the 6 fields in loadavg
Patch series "Fix some seq_file users that were recently broken".
A recent change to seq_file broke some users which were using seq_file
in a non-"standard" way ... though the "standard" isn't documented, so
they can be excused. The result is a possible leak - of memory in one
case, of references to a 'transport' in the other.
These three patches:
1/ document and explain the problem
2/ fix the problem user in x86
3/ fix the problem user in net/sctp
This patch (of 3):
Users of seq_file will sometimes find it convenient to take a resource,
such as a lock or memory allocation, in the ->start or ->next operations.
These are per-entry resources, distinct from per-session resources which
are taken in ->start and released in ->stop.
The preferred management of these is release the resource on the
subsequent call to ->next or ->stop.
However prior to Commit 1f4aace60b ("fs/seq_file.c: simplify seq_file
iteration code and interface") it happened that ->show would always be
called after ->start or ->next, and a few users chose to release the
resource in ->show.
This is no longer reliable. Since the mentioned commit, ->next will
always come after a successful ->show (to ensure m->index is updated
correctly), so the original ordering cannot be maintained.
This patch updates the documentation to clearly state the required
behaviour. Other patches will fix the few problematic users.
[akpm@linux-foundation.org: fix typo, per Willy]
Link: https://lkml.kernel.org/r/161248518659.21478.2484341937387294998.stgit@noble1
Link: https://lkml.kernel.org/r/161248539020.21478.3147971477400875336.stgit@noble1
Fixes: 1f4aace60b ("fs/seq_file.c: simplify seq_file iteration code and interface")
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix indentation snafu in proc.rst as reported by Stephen.
next-20210219/Documentation/filesystems/proc.rst:697: WARNING: Unexpected indentation.
Fixes: 93ea4a0b8f ("Documentation: proc.rst: add more about the 6 fields in loadavg")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/20210223060418.21443-1-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Merge tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdfhttps://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
1d7b902e28
In order to support idmapped mounts, filesystems need to be changed
and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
patches to convert individual filesystem are not very large or
complicated overall as can be seen from the included fat, ext4, and
xfs ports. Patches for other filesystems are actively worked on and
will be sent out separately. The xfstestsuite can be used to verify
that port has been done correctly.
The mount_setattr() syscall is motivated independent of the idmapped
mounts patches and it's been around since July 2019. One of the most
valuable features of the new mount api is the ability to perform
mounts based on file descriptors only.
Together with the lookup restrictions available in the openat2()
RESOLVE_* flag namespace which we added in v5.6 this is the first time
we are close to hardened and race-free (e.g. symlinks) mounting and
path resolution.
While userspace has started porting to the new mount api to mount
proper filesystems and create new bind-mounts it is currently not
possible to change mount options of an already existing bind mount in
the new mount api since the mount_setattr() syscall is missing.
With the addition of the mount_setattr() syscall we remove this last
restriction and userspace can now fully port to the new mount api,
covering every use-case the old mount api could. We also add the
crucial ability to recursively change mount options for a whole mount
tree, both removing and adding mount options at the same time. This
syscall has been requested multiple times by various people and
projects.
There is a simple tool available at
https://github.com/brauner/mount-idmapped
that allows to create idmapped mounts so people can play with this
patch series. I'll add support for the regular mount binary should you
decide to pull this in the following weeks:
Here's an example to a simple idmapped mount of another user's home
directory:
u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt
u1001@f2-vm:/$ ls -al /home/ubuntu/
total 28
drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
drwxr-xr-x 4 root root 4096 Oct 28 04:00 ..
-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .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
u1001@f2-vm:/$ ls -al /mnt/
total 28
drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 .
drwxr-xr-x 29 root root 4096 Oct 28 22:01 ..
-rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile
-rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ touch /mnt/my-file
u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file
u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file
u1001@f2-vm:/$ ls -al /mnt/my-file
-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file
u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file
u1001@f2-vm:/$ getfacl /mnt/my-file
getfacl: Removing leading '/' from absolute path names
# file: mnt/my-file
# owner: u1001
# group: u1001
user::rw-
user:u1001:rwx
group::rw-
mask::rwx
other::r--
u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
getfacl: Removing leading '/' from absolute path names
# file: home/ubuntu/my-file
# owner: ubuntu
# group: ubuntu
user::rw-
user:ubuntu:rwx
group::rw-
mask::rwx
other::r--"
* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
xfs: support idmapped mounts
ext4: support idmapped mounts
fat: handle idmapped mounts
tests: add mount_setattr() selftests
fs: introduce MOUNT_ATTR_IDMAP
fs: add mount_setattr()
fs: add attr_flags_to_mnt_flags helper
fs: split out functions to hold writers
namespace: only take read lock in do_reconfigure_mnt()
mount: make {lock,unlock}_mount_hash() static
namespace: take lock_mount_hash() directly when changing flags
nfs: do not export idmapped mounts
overlayfs: do not mount on top of idmapped mounts
ecryptfs: do not mount on top of idmapped mounts
ima: handle idmapped mounts
apparmor: handle idmapped mounts
fs: make helpers idmap mount aware
exec: handle idmapped mounts
would_dump: handle idmapped mounts
...
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Merge tag 'lazytime_for_v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull lazytime updates from Jan Kara:
"Cleanups of the lazytime handling in the writeback code making rules
for calling ->dirty_inode() filesystem handlers saner"
* tag 'lazytime_for_v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
ext4: simplify i_state checks in __ext4_update_other_inode_time()
gfs2: don't worry about I_DIRTY_TIME in gfs2_fsync()
fs: improve comments for writeback_single_inode()
fs: drop redundant check from __writeback_single_inode()
fs: clean up __mark_inode_dirty() a bit
fs: pass only I_DIRTY_INODE flags to ->dirty_inode
fs: don't call ->dirty_inode for lazytime timestamp updates
fat: only specify I_DIRTY_TIME when needed in fat_update_time()
fs: only specify I_DIRTY_TIME when needed in generic_update_time()
fs: correctly document the inode dirty flags
Address Jon's feedback on the previous patch by adding info about
field separators in the /proc/loadavg file.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20210222034729.22350-1-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
- As promised, the minimum Sphinx version to build the docs is now 1.7,
and we have dropped support for Python 2 entirely. That allowed the
removal of a bunch of compatibility code.
- A set of treewide warning fixups from Mauro that I applied after it
became clear nobody else was going to deal with them.
- The automarkup mechanism can now create cross-references from relative
paths to RST files.
- More translations, typo fixes, and warning fixes.
No conflicts with any other tree as far as I know.
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Merge tag 'docs-5.12' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"It has been a relatively quiet cycle in docsland.
- As promised, the minimum Sphinx version to build the docs is now
1.7, and we have dropped support for Python 2 entirely. That
allowed the removal of a bunch of compatibility code.
- A set of treewide warning fixups from Mauro that I applied after it
became clear nobody else was going to deal with them.
- The automarkup mechanism can now create cross-references from
relative paths to RST files.
- More translations, typo fixes, and warning fixes"
* tag 'docs-5.12' of git://git.lwn.net/linux: (75 commits)
docs: kernel-hacking: be more civil
docs: Remove the Microsoft rhetoric
Documentation/admin-guide: kernel-parameters: Update nohlt section
doc/admin-guide: fix spelling mistake: "perfomance" -> "performance"
docs: Document cross-referencing using relative path
docs: Enable usage of relative paths to docs on automarkup
docs: thermal: fix spelling mistakes
Documentation: admin-guide: Update kvm/xen config option
docs: Make syscalls' helpers naming consistent
coding-style.rst: Avoid comma statements
Documentation: /proc/loadavg: add 3 more field descriptions
Documentation/submitting-patches: Add blurb about backtraces in commit messages
Docs: drop Python 2 support
Move our minimum Sphinx version to 1.7
Documentation: input: define ABS_PRESSURE/ABS_MT_PRESSURE resolution as grams
scripts/kernel-doc: add internal hyperlink to DOC: sections
Update Documentation/admin-guide/sysctl/fs.rst
docs: Update DTB format references
docs: zh_CN: add iio index.rst translation
docs/zh_CN: add iio ep93xx_adc.rst translation
...
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Merge tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block
Pull core block updates from Jens Axboe:
"Another nice round of removing more code than what is added, mostly
due to Christoph's relentless pursuit of tech debt removal/cleanups.
This pull request contains:
- Two series of BFQ improvements (Paolo, Jan, Jia)
- Block iov_iter improvements (Pavel)
- bsg error path fix (Pan)
- blk-mq scheduler improvements (Jan)
- -EBUSY discard fix (Jan)
- bvec allocation improvements (Ming, Christoph)
- bio allocation and init improvements (Christoph)
- Store bdev pointer in bio instead of gendisk + partno (Christoph)
- Block trace point cleanups (Christoph)
- hard read-only vs read-only split (Christoph)
- Block based swap cleanups (Christoph)
- Zoned write granularity support (Damien)
- Various fixes/tweaks (Chunguang, Guoqing, Lei, Lukas, Huhai)"
* tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block: (104 commits)
mm: simplify swapdev_block
sd_zbc: clear zone resources for non-zoned case
block: introduce blk_queue_clear_zone_settings()
zonefs: use zone write granularity as block size
block: introduce zone_write_granularity limit
block: use blk_queue_set_zoned in add_partition()
nullb: use blk_queue_set_zoned() to setup zoned devices
nvme: cleanup zone information initialization
block: document zone_append_max_bytes attribute
block: use bi_max_vecs to find the bvec pool
md/raid10: remove dead code in reshape_request
block: mark the bio as cloned in bio_iov_bvec_set
block: set BIO_NO_PAGE_REF in bio_iov_bvec_set
block: remove a layer of indentation in bio_iov_iter_get_pages
block: turn the nr_iovecs argument to bio_alloc* into an unsigned short
block: remove the 1 and 4 vec bvec_slabs entries
block: streamline bvec_alloc
block: factor out a bvec_alloc_gfp helper
block: move struct biovec_slab to bio.c
block: reuse BIO_INLINE_VECS for integrity bvecs
...
Add an ioctl which allows reading fs-verity metadata from a file.
This is useful when a file with fs-verity enabled needs to be served
somewhere, and the other end wants to do its own fs-verity compatible
verification of the file. See the commit messages for details.
This new ioctl has been tested using new xfstests I've written for it.
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Merge tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt
Pull fsverity updates from Eric Biggers:
"Add an ioctl which allows reading fs-verity metadata from a file.
This is useful when a file with fs-verity enabled needs to be served
somewhere, and the other end wants to do its own fs-verity compatible
verification of the file. See the commit messages for details.
This new ioctl has been tested using new xfstests I've written for it"
* tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
fs-verity: support reading signature with ioctl
fs-verity: support reading descriptor with ioctl
fs-verity: support reading Merkle tree with ioctl
fs-verity: add FS_IOC_READ_VERITY_METADATA ioctl
fs-verity: don't pass whole descriptor to fsverity_verify_signature()
fs-verity: factor out fsverity_get_descriptor()
We've added two major features: 1) compression level and 2) checkpoint_merge, in
this round. 1) compression level expands 'compress_algorithm' mount option to
accept parameter as format of <algorithm>:<level>, by this way, it gives a way
to allow user to do more specified config on lz4 and zstd compression level,
then f2fs compression can provide higher compress ratio. 2) checkpoint_merge
creates a kernel daemon and makes it to merge concurrent checkpoint requests as
much as possible to eliminate redundant checkpoint issues. Plus, we can
eliminate the sluggish issue caused by slow checkpoint operation when the
checkpoint is done in a process context in a cgroup having low i/o budget and
cpu shares.
Enhancement:
- add compress level for lz4 and zstd in mount option
- checkpoint_merge mount option
- deprecate f2fs_trace_io
Bug fix:
- flush data when enabling checkpoint back
- handle corner cases of mount options
- missing ACL update and lock for I_LINKABLE flag
- attach FIEMAP_EXTENT_MERGED in f2fs_fiemap
- fix potential deadlock in compression flow
- fix wrong submit_io condition
As usual, we've cleaned up many code flows and fixed minor bugs.
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Merge tag 'f2fs-for-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"We've added two major features: 1) compression level and 2)
checkpoint_merge, in this round.
Compression level expands 'compress_algorithm' mount option to accept
parameter as format of <algorithm>:<level>, by this way, it gives a
way to allow user to do more specified config on lz4 and zstd
compression level, then f2fs compression can provide higher compress
ratio.
checkpoint_merge creates a kernel daemon and makes it to merge
concurrent checkpoint requests as much as possible to eliminate
redundant checkpoint issues. Plus, we can eliminate the sluggish issue
caused by slow checkpoint operation when the checkpoint is done in a
process context in a cgroup having low i/o budget and cpu shares.
Enhancements:
- add compress level for lz4 and zstd in mount option
- checkpoint_merge mount option
- deprecate f2fs_trace_io
Bug fixes:
- flush data when enabling checkpoint back
- handle corner cases of mount options
- missing ACL update and lock for I_LINKABLE flag
- attach FIEMAP_EXTENT_MERGED in f2fs_fiemap
- fix potential deadlock in compression flow
- fix wrong submit_io condition
As usual, we've cleaned up many code flows and fixed minor bugs"
* tag 'f2fs-for-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (32 commits)
Documentation: f2fs: fix typo s/automaic/automatic
f2fs: give a warning only for readonly partition
f2fs: don't grab superblock freeze for flush/ckpt thread
f2fs: add ckpt_thread_ioprio sysfs node
f2fs: introduce checkpoint_merge mount option
f2fs: relocate inline conversion from mmap() to mkwrite()
f2fs: fix a wrong condition in __submit_bio
f2fs: remove unnecessary initialization in xattr.c
f2fs: fix to avoid inconsistent quota data
f2fs: flush data when enabling checkpoint back
f2fs: deprecate f2fs_trace_io
f2fs: Remove readahead collision detection
f2fs: remove unused stat_{inc, dec}_atomic_write
f2fs: introduce sb_status sysfs node
f2fs: fix to use per-inode maxbytes
f2fs: compress: fix potential deadlock
libfs: unexport generic_ci_d_compare() and generic_ci_d_hash()
f2fs: fix to set/clear I_LINKABLE under i_lock
f2fs: fix null page reference in redirty_blocks
f2fs: clean up post-read processing
...
Add support for FS_VERITY_METADATA_TYPE_SIGNATURE to
FS_IOC_READ_VERITY_METADATA. This allows a userspace server program to
retrieve the built-in signature (if present) of a verity file for
serving to a client which implements fs-verity compatible verification.
See the patch which introduced FS_IOC_READ_VERITY_METADATA for more
details.
The ability for userspace to read the built-in signatures is also useful
because it allows a system that is using the in-kernel signature
verification to migrate to userspace signature verification.
This has been tested using a new xfstest which calls this ioctl via a
new subcommand for the 'fsverity' program from fsverity-utils.
Link: https://lore.kernel.org/r/20210115181819.34732-7-ebiggers@kernel.org
Reviewed-by: Victor Hsieh <victorhsieh@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Add support for FS_VERITY_METADATA_TYPE_DESCRIPTOR to
FS_IOC_READ_VERITY_METADATA. This allows a userspace server program to
retrieve the fs-verity descriptor of a file for serving to a client
which implements fs-verity compatible verification. See the patch which
introduced FS_IOC_READ_VERITY_METADATA for more details.
"fs-verity descriptor" here means only the part that userspace cares
about because it is hashed to produce the file digest. It doesn't
include the signature which ext4 and f2fs append to the
fsverity_descriptor struct when storing it on-disk, since that way of
storing the signature is an implementation detail. The next patch adds
a separate metadata_type value for retrieving the signature separately.
This has been tested using a new xfstest which calls this ioctl via a
new subcommand for the 'fsverity' program from fsverity-utils.
Link: https://lore.kernel.org/r/20210115181819.34732-6-ebiggers@kernel.org
Reviewed-by: Victor Hsieh <victorhsieh@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Add support for FS_VERITY_METADATA_TYPE_MERKLE_TREE to
FS_IOC_READ_VERITY_METADATA. This allows a userspace server program to
retrieve the Merkle tree of a verity file for serving to a client which
implements fs-verity compatible verification. See the patch which
introduced FS_IOC_READ_VERITY_METADATA for more details.
This has been tested using a new xfstest which calls this ioctl via a
new subcommand for the 'fsverity' program from fsverity-utils.
Link: https://lore.kernel.org/r/20210115181819.34732-5-ebiggers@kernel.org
Reviewed-by: Victor Hsieh <victorhsieh@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Add an ioctl FS_IOC_READ_VERITY_METADATA which will allow reading verity
metadata from a file that has fs-verity enabled, including:
- The Merkle tree
- The fsverity_descriptor (not including the signature if present)
- The built-in signature, if present
This ioctl has similar semantics to pread(). It is passed the type of
metadata to read (one of the above three), and a buffer, offset, and
size. It returns the number of bytes read or an error.
Separate patches will add support for each of the above metadata types.
This patch just adds the ioctl itself.
This ioctl doesn't make any assumption about where the metadata is
stored on-disk. It does assume the metadata is in a stable format, but
that's basically already the case:
- The Merkle tree and fsverity_descriptor are defined by how fs-verity
file digests are computed; see the "File digest computation" section
of Documentation/filesystems/fsverity.rst. Technically, the way in
which the levels of the tree are ordered relative to each other wasn't
previously specified, but it's logical to put the root level first.
- The built-in signature is the value passed to FS_IOC_ENABLE_VERITY.
This ioctl is useful because it allows writing a server program that
takes a verity file and serves it to a client program, such that the
client can do its own fs-verity compatible verification of the file.
This only makes sense if the client doesn't trust the server and if the
server needs to provide the storage for the client.
More concretely, there is interest in using this ability in Android to
export APK files (which are protected by fs-verity) to "protected VMs".
This would use Protected KVM (https://lwn.net/Articles/836693), which
provides an isolated execution environment without having to trust the
traditional "host". A "guest" VM can boot from a signed image and
perform specific tasks in a minimum trusted environment using files that
have fs-verity enabled on the host, without trusting the host or
requiring that the guest has its own trusted storage.
Technically, it would be possible to duplicate the metadata and store it
in separate files for serving. However, that would be less efficient
and would require extra care in userspace to maintain file consistency.
In addition to the above, the ability to read the built-in signatures is
useful because it allows a system that is using the in-kernel signature
verification to migrate to userspace signature verification.
Link: https://lore.kernel.org/r/20210115181819.34732-4-ebiggers@kernel.org
Reviewed-by: Victor Hsieh <victorhsieh@google.com>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
We've added a new mount options, "checkpoint_merge" and "nocheckpoint_merge",
which creates a kernel daemon and makes it to merge concurrent checkpoint
requests as much as possible to eliminate redundant checkpoint issues. Plus,
we can eliminate the sluggish issue caused by slow checkpoint operation
when the checkpoint is done in a process context in a cgroup having
low i/o budget and cpu shares. To make this do better, we set the
default i/o priority of the kernel daemon to "3", to give one higher
priority than other kernel threads. The below verification result
explains this.
The basic idea has come from https://opensource.samsung.com.
[Verification]
Android Pixel Device(ARM64, 7GB RAM, 256GB UFS)
Create two I/O cgroups (fg w/ weight 100, bg w/ wight 20)
Set "strict_guarantees" to "1" in BFQ tunables
In "fg" cgroup,
- thread A => trigger 1000 checkpoint operations
"for i in `seq 1 1000`; do touch test_dir1/file; fsync test_dir1;
done"
- thread B => gererating async. I/O
"fio --rw=write --numjobs=1 --bs=128k --runtime=3600 --time_based=1
--filename=test_img --name=test"
In "bg" cgroup,
- thread C => trigger repeated checkpoint operations
"echo $$ > /dev/blkio/bg/tasks; while true; do touch test_dir2/file;
fsync test_dir2; done"
We've measured thread A's execution time.
[ w/o patch ]
Elapsed Time: Avg. 68 seconds
[ w/ patch ]
Elapsed Time: Avg. 48 seconds
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
[Jaegeuk Kim: fix the return value in f2fs_start_ckpt_thread, reported by Dan]
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Overlayfs's volatile option allows the user to bypass all forced sync calls
to the upperdir filesystem. This comes at the cost of safety. We can never
ensure that the user's data is intact, but we can make a best effort to
expose whether or not the data is likely to be in a bad state.
The best way to handle this in the time being is that if an overlayfs's
upperdir experiences an error after a volatile mount occurs, that error
will be returned on fsync, fdatasync, sync, and syncfs. This is
contradictory to the traditional behaviour of VFS which fails the call
once, and only raises an error if a subsequent fsync error has occurred,
and been raised by the filesystem.
One awkward aspect of the patch is that we have to manually set the
superblock's errseq_t after the sync_fs callback as opposed to just
returning an error from syncfs. This is because the call chain looks
something like this:
sys_syncfs ->
sync_filesystem ->
__sync_filesystem ->
/* The return value is ignored here
sb->s_op->sync_fs(sb)
_sync_blockdev
/* Where the VFS fetches the error to raise to userspace */
errseq_check_and_advance
Because of this we call errseq_set every time the sync_fs callback occurs.
Due to the nature of this seen / unseen dichotomy, if the upperdir is an
inconsistent state at the initial mount time, overlayfs will refuse to
mount, as overlayfs cannot get a snapshot of the upperdir's errseq that
will increment on error until the user calls syncfs.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Suggested-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Fixes: c86243b090 ("ovl: provide a mount option "volatile"")
Cc: stable@vger.kernel.org
Reviewed-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Expand 'compress_algorithm' mount option to accept parameter as format of
<algorithm>:<level>, by this way, it gives a way to allow user to do more
specified config on lz4 and zstd compression level, then f2fs compression
can provide higher compress ratio.
In order to set compress level for lz4 algorithm, it needs to set
CONFIG_LZ4HC_COMPRESS and CONFIG_F2FS_FS_LZ4HC config to enable lz4hc
compress algorithm.
CR and performance number on lz4/lz4hc algorithm:
dd if=enwik9 of=compressed_file conv=fsync
Original blocks: 244382
lz4 lz4hc-9
compressed blocks 170647 163270
compress ratio 69.8% 66.8%
speed 16.4207 s, 60.9 MB/s 26.7299 s, 37.4 MB/s
compress ratio = after / before
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Sleeping bio allocations do not fail, which means that injecting an error
into sleeping bio allocations is a little silly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The block layer spends quite a while in blkdev_direct_IO() to copy and
initialise bio's bvec. However, if we've already got a bvec in the input
iterator it might be reused in some cases, i.e. when new
ITER_BVEC_FLAG_FIXED flag is set. Simple tests show considerable
performance boost, and it also reduces memory footprint.
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
zero-length bvec segments are allowed in general, but not handled by bio
and down the block layer so filtered out. This inconsistency may be
confusing and prevent from optimisations. As zero-length segments are
useless and places that were generating them are patched, declare them
not allowed.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
The posix acl permission checking helpers determine whether a caller is
privileged over an inode according to the acls associated with the
inode. Add helpers that make it possible to handle acls on idmapped
mounts.
The vfs and the filesystems targeted by this first iteration make use of
posix_acl_fix_xattr_from_user() and posix_acl_fix_xattr_to_user() to
translate basic posix access and default permissions such as the
ACL_USER and ACL_GROUP type according to the initial user namespace (or
the superblock's user namespace) to and from the caller's current user
namespace. Adapt these two helpers to handle idmapped mounts whereby we
either map from or into the mount's user namespace depending on in which
direction we're translating.
Similarly, cap_convert_nscap() is used by the vfs to translate user
namespace and non-user namespace aware filesystem capabilities from the
superblock's user namespace to the caller's user namespace. Enable it to
handle idmapped mounts by accounting for the mount's user namespace.
In addition the fileystems targeted in the first iteration of this patch
series make use of the posix_acl_chmod() and, posix_acl_update_mode()
helpers. Both helpers perform permission checks on the target inode. Let
them handle idmapped mounts. These two helpers are called when posix
acls are set by the respective filesystems to handle this case we extend
the ->set() method to take an additional user namespace argument to pass
the mount's user namespace down.
Link: https://lore.kernel.org/r/20210121131959.646623-9-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>
->dirty_inode is now only called when I_DIRTY_INODE (I_DIRTY_SYNC and/or
I_DIRTY_DATASYNC) is set. However it may still be passed other dirty
flags at the same time, provided that these other flags happened to be
passed to __mark_inode_dirty() at the same time as I_DIRTY_INODE.
This doesn't make sense because there is no reason for filesystems to
care about these extra flags. Nor are filesystems notified about all
updates to these other flags.
Therefore, mask the flags before passing them to ->dirty_inode.
Also properly document ->dirty_inode in vfs.rst.
Link: https://lore.kernel.org/r/20210112190253.64307-7-ebiggers@kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
The documentation for other filesystems is already included via
filesystems/index.rst. Include ext4 in the same way and remove it
from the top-level table of contents.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20210101215215.1047826-1-j.neuschaefer@gmx.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
After commit 77573fa310 ("fs: Kill DCACHE_DONTCACHE dentry even if
DCACHE_REFERENCED is set"), changes to DAX policy will take effect
as soon as all references to this file are gone.
Update the documentation accordingly.
Signed-off-by: Hao Li <lihao2018.fnst@cn.fujitsu.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20210106015000.5263-1-lihao2018.fnst@cn.fujitsu.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
There's no need for mnt_want_write_file() to increment mnt_writers when
the file is already open for writing, provided that
mnt_drop_write_file() is changed to conditionally decrement it.
We seem to have ended up in the current situation because
mnt_want_write_file() used to be paired with mnt_drop_write(), due to
mnt_drop_write_file() not having been added yet. So originally
mnt_want_write_file() had to always increment mnt_writers.
But later mnt_drop_write_file() was added, and all callers of
mnt_want_write_file() were paired with it. This makes the compatibility
between mnt_want_write_file() and mnt_drop_write() no longer necessary.
Therefore, make __mnt_want_write_file() and __mnt_drop_write_file() skip
incrementing mnt_writers on files already open for writing. This
removes the only caller of mnt_clone_write(), so remove that too.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
