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Merge tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull directory locking updates from Christian Brauner:
"This contains the work to add centralized APIs for directory locking
operations.
This series is part of a larger effort to change directory operation
locking to allow multiple concurrent operations in a directory. The
ultimate goal is to lock the target dentry(s) rather than the whole
parent directory.
To help with changing the locking protocol, this series centralizes
locking and lookup in new helper functions. The helpers establish a
pattern where it is the dentry that is being locked and unlocked
(currently the lock is held on dentry->d_parent->d_inode, but that can
change in the future).
This also changes vfs_mkdir() to unlock the parent on failure, as well
as dput()ing the dentry. This allows end_creating() to only require
the target dentry (which may be IS_ERR() after vfs_mkdir()), not the
parent"
* tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
nfsd: fix end_creating() conversion
VFS: introduce end_creating_keep()
VFS: change vfs_mkdir() to unlock on failure.
ecryptfs: use new start_creating/start_removing APIs
Add start_renaming_two_dentries()
VFS/ovl/smb: introduce start_renaming_dentry()
VFS/nfsd/ovl: introduce start_renaming() and end_renaming()
VFS: add start_creating_killable() and start_removing_killable()
VFS: introduce start_removing_dentry()
smb/server: use end_removing_noperm for for target of smb2_create_link()
VFS: introduce start_creating_noperm() and start_removing_noperm()
VFS/nfsd/cachefiles/ovl: introduce start_removing() and end_removing()
VFS/nfsd/cachefiles/ovl: add start_creating() and end_creating()
VFS: tidy up do_unlinkat()
VFS: introduce start_dirop() and end_dirop()
debugfs: rename end_creating() to debugfs_end_creating()
Several callers perform a rename on a dentry they already have, and only
require lookup for the target name. This includes smb/server and a few
different places in overlayfs.
start_renaming_dentry() performs the required lookup and takes the
required lock using lock_rename_child()
It is used in three places in overlayfs and in ksmbd_vfs_rename().
In the ksmbd case, the parent of the source is not important - the
source must be renamed from wherever it is. So start_renaming_dentry()
allows rd->old_parent to be NULL and only checks it if it is non-NULL.
On success rd->old_parent will be the parent of old_dentry with an extra
reference taken. Other start_renaming function also now take the extra
reference and end_renaming() now drops this reference as well.
ovl_lookup_temp(), ovl_parent_lock(), and ovl_parent_unlock() are
all removed as they are no longer needed.
OVL_TEMPNAME_SIZE and ovl_tempname() are now declared in overlayfs.h so
that ovl_check_rename_whiteout() can access them.
ovl_copy_up_workdir() now always cleans up on error.
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20251113002050.676694-12-neilb@ownmail.net
Tested-by: syzbot@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
start_renaming() combines name lookup and locking to prepare for rename.
It is used when two names need to be looked up as in nfsd and overlayfs -
cases where one or both dentries are already available will be handled
separately.
__start_renaming() avoids the inode_permission check and hash
calculation and is suitable after filename_parentat() in do_renameat2().
It subsumes quite a bit of code from that function.
start_renaming() does calculate the hash and check X permission and is
suitable elsewhere:
- nfsd_rename()
- ovl_rename()
In ovl, ovl_do_rename_rd() is factored out of ovl_do_rename(), which
itself will be gone by the end of the series.
Acked-by: Chuck Lever <chuck.lever@oracle.com> (for nfsd parts)
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
--
Changes since v3:
- added missig dput() in ovl_rename when "whiteout" is not-NULL.
Changes since v2:
- in __start_renaming() some label have been renamed, and err
is always set before a "goto out_foo" rather than passing the
error in a dentry*.
- ovl_do_rename() changed to call the new ovl_do_rename_rd() rather
than keeping duplicate code
- code around ovl_cleanup() call in ovl_rename() restructured.
Link: https://patch.msgid.link/20251113002050.676694-11-neilb@ownmail.net
Tested-by: syzbot@syzkaller.appspotmail.com
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
start_removing() is similar to start_creating() but will only return a
positive dentry with the expectation that it will be removed. This is
used by nfsd, cachefiles, and overlayfs. They are changed to also use
end_removing() to terminate the action begun by start_removing(). This
is a simple alias for end_dirop().
Apart from changes to the error paths, as we no longer need to unlock on
a lookup error, an effect on callers is that they don't need to test if
the found dentry is positive or negative - they can be sure it is
positive.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20251113002050.676694-6-neilb@ownmail.net
Tested-by: syzbot@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
start_creating() is similar to simple_start_creating() but is not so
simple.
It takes a qstr for the name, includes permission checking, and does NOT
report an error if the name already exists, returning a positive dentry
instead.
This is currently used by nfsd, cachefiles, and overlayfs.
end_creating() is called after the dentry has been used.
end_creating() drops the reference to the dentry as it is generally no
longer needed. This is exactly the first section of end_creating_path()
so that function is changed to call the new end_creating()
These calls help encapsulate locking rules so that directory locking can
be changed.
Occasionally this change means that the parent lock is held for a
shorter period of time, for example in cachefiles_commit_tmpfile().
As this function now unlocks after an unlink and before the following
lookup, it is possible that the lookup could again find a positive
dentry, so a while loop is introduced there.
In overlayfs the ovl_lookup_temp() function has ovl_tempname()
split out to be used in ovl_start_creating_temp(). The other use
of ovl_lookup_temp() is preparing for a rename. When rename handling
is updated, ovl_lookup_temp() will be removed.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20251113002050.676694-5-neilb@ownmail.net
Tested-by: syzbot@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
In order to add directory delegation support, we must break delegations
on the parent on any change to the directory.
Add a delegated_inode parameter to vfs_symlink() and have it break the
delegation. do_symlinkat() can then wait on the delegation break before
proceeding.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-12-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
In order to add directory delegation support, we need to break
delegations on the parent whenever there is going to be a change in the
directory.
Add a new delegated_inode pointer to vfs_mknod() and have the
appropriate callers wait when there is an outstanding delegation. All
other callers just set the pointer to NULL.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-11-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
In order to add directory delegation support, we need to break
delegations on the parent whenever there is going to be a change in the
directory.
Add a delegated_inode parameter to vfs_create. Most callers are
converted to pass in NULL, but do_mknodat() is changed to wait for a
delegation break if there is one.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-10-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
As Neil points out:
"I would be in favour of dropping the "dir" arg because it is always
d_inode(dentry->d_parent) which is stable."
...and...
"Also *every* caller of vfs_create() passes ".excl = true". So maybe we
don't need that arg at all."
Drop both arguments from vfs_create() and fix up the callers.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-9-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
In order to add directory delegation support, we need to break
delegations on the parent whenever there is going to be a change in the
directory.
Add a delegated_inode struct to vfs_rmdir() and populate that
pointer with the parent inode if it's non-NULL. Most existing in-kernel
callers pass in a NULL pointer.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-7-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
In order to add directory delegation support, we need to break
delegations on the parent whenever there is going to be a change in the
directory.
Add a new delegated_inode parameter to vfs_mkdir. All of the existing
callers set that to NULL for now, except for do_mkdirat which will
properly block until the lease is gone.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-6-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-f_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull file->f_path constification from Al Viro:
"Only one thing was modifying ->f_path of an opened file - acct(2).
Massaging that away and constifying a bunch of struct path * arguments
in functions that might be given &file->f_path ends up with the
situation where we can turn ->f_path into an anon union of const
struct path f_path and struct path __f_path, the latter modified only
in a few places in fs/{file_table,open,namei}.c, all for struct file
instances that are yet to be opened"
* tag 'pull-f_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (23 commits)
Have cc(1) catch attempts to modify ->f_path
kernel/acct.c: saner struct file treatment
configfs:get_target() - release path as soon as we grab configfs_item reference
apparmor/af_unix: constify struct path * arguments
ovl_is_real_file: constify realpath argument
ovl_sync_file(): constify path argument
ovl_lower_dir(): constify path argument
ovl_get_verity_digest(): constify path argument
ovl_validate_verity(): constify {meta,data}path arguments
ovl_ensure_verity_loaded(): constify datapath argument
ksmbd_vfs_set_init_posix_acl(): constify path argument
ksmbd_vfs_inherit_posix_acl(): constify path argument
ksmbd_vfs_kern_path_unlock(): constify path argument
ksmbd_vfs_path_lookup_locked(): root_share_path can be const struct path *
check_export(): constify path argument
export_operations->open(): constify path argument
rqst_exp_get_by_name(): constify path argument
nfs: constify path argument of __vfs_getattr()
bpf...d_path(): constify path argument
done_path_create(): constify path argument
...
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Merge tag 'ovl-update-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs
Pull overlayfs updates from Amir Goldstein:
- Work by André Almeida to support case-insensitive overlayfs
Underlying case-insensitive filesystems casefolding is per directory,
but for overlayfs it is all-or-nothing. It supports layers where all
directories are casefolded (with same encoding) or layers where no
directories are casefolded.
- A fix for a "bug" in Neil's ovl directory lock changes, which only
manifested itself with casefold enabled layers which may return an
unhashed negative dentry from lookup.
* tag 'ovl-update-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs:
ovl: make sure that ovl_create_real() returns a hashed dentry
ovl: Support mounting case-insensitive enabled layers
ovl: Check for casefold consistency when creating new dentries
ovl: Add S_CASEFOLD as part of the inode flag to be copied
ovl: Set case-insensitive dentry operations for ovl sb
ovl: Ensure that all layers have the same encoding
ovl: Create ovl_casefold() to support casefolded strncmp()
ovl: Prepare for mounting case-insensitive enabled layers
fs: Create sb_same_encoding() helper
fs: Create sb_encoding() helper
A rename operation can only rename within a single mount. Callers of
vfs_rename() must and do ensure this is the case.
So there is no point in having two mnt_idmaps in renamedata as they are
always the same. Only one of them is passed to ->rename in any case.
This patch replaces both with a single "mnt_idmap" and changes all
callers.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Christian Brauner <brauner@kernel.org>
To keep ovl's inodes consistent with their real inodes, create a new
mask for inode file attributes that needs to be copied. Add the
S_CASEFOLD flag as part of the flags that need to be copied along with
the other file attributes.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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Merge tag 'vfs-6.17-rc1.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull fileattr updates from Christian Brauner:
"This introduces the new file_getattr() and file_setattr() system calls
after lengthy discussions.
Both system calls serve as successors and extensible companions to
the FS_IOC_FSGETXATTR and FS_IOC_FSSETXATTR system calls which have
started to show their age in addition to being named in a way that
makes it easy to conflate them with extended attribute related
operations.
These syscalls allow userspace to set filesystem inode attributes on
special files. One of the usage examples is the XFS quota projects.
XFS has project quotas which could be attached to a directory. All new
inodes in these directories inherit project ID set on parent
directory.
The project is created from userspace by opening and calling
FS_IOC_FSSETXATTR on each inode. This is not possible for special
files such as FIFO, SOCK, BLK etc. Therefore, some inodes are left
with empty project ID. Those inodes then are not shown in the quota
accounting but still exist in the directory. This is not critical but
in the case when special files are created in the directory with
already existing project quota, these new inodes inherit extended
attributes. This creates a mix of special files with and without
attributes. Moreover, special files with attributes don't have a
possibility to become clear or change the attributes. This, in turn,
prevents userspace from re-creating quota project on these existing
files.
In addition, these new system calls allow the implementation of
additional attributes that we couldn't or didn't want to fit into the
legacy ioctls anymore"
* tag 'vfs-6.17-rc1.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: tighten a sanity check in file_attr_to_fileattr()
tree-wide: s/struct fileattr/struct file_kattr/g
fs: introduce file_getattr and file_setattr syscalls
fs: prepare for extending file_get/setattr()
fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP
selinux: implement inode_file_[g|s]etattr hooks
lsm: introduce new hooks for setting/getting inode fsxattr
fs: split fileattr related helpers into separate file
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Merge tag 'vfs-6.17-rc1.ovl' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull overlayfs updates from Christian Brauner:
"This contains overlayfs updates for this cycle.
The changes for overlayfs in here are primarily focussed on preparing
for some proposed changes to directory locking.
Overlayfs currently will sometimes lock a directory on the upper
filesystem and do a few different things while holding the lock. This
is incompatible with the new potential scheme.
This series narrows the region of code protected by the directory
lock, taking it multiple times when necessary. This theoretically
opens up the possibilty of other changes happening on the upper
filesytem between the unlock and the lock. To some extent the patches
guard against that by checking the dentries still have the expect
parent after retaking the lock. In general, concurrent changes to the
upper and lower filesystems aren't supported properly anyway"
* tag 'vfs-6.17-rc1.ovl' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (25 commits)
ovl: properly print correct variable
ovl: rename ovl_cleanup_unlocked() to ovl_cleanup()
ovl: change ovl_create_real() to receive dentry parent
ovl: narrow locking in ovl_check_rename_whiteout()
ovl: narrow locking in ovl_whiteout()
ovl: change ovl_cleanup_and_whiteout() to take rename lock as needed
ovl: narrow locking on ovl_remove_and_whiteout()
ovl: change ovl_workdir_cleanup() to take dir lock as needed.
ovl: narrow locking in ovl_workdir_cleanup_recurse()
ovl: narrow locking in ovl_indexdir_cleanup()
ovl: narrow locking in ovl_workdir_create()
ovl: narrow locking in ovl_cleanup_index()
ovl: narrow locking in ovl_cleanup_whiteouts()
ovl: narrow locking in ovl_rename()
ovl: simplify gotos in ovl_rename()
ovl: narrow locking in ovl_create_over_whiteout()
ovl: narrow locking in ovl_clear_empty()
ovl: narrow locking in ovl_create_upper()
ovl: narrow the locked region in ovl_copy_up_workdir()
ovl: Call ovl_create_temp() without lock held.
...
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Merge tag 'vfs-6.17-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc VFS updates from Christian Brauner:
"This contains the usual selections of misc updates for this cycle.
Features:
- Add ext4 IOCB_DONTCACHE support
This refactors the address_space_operations write_begin() and
write_end() callbacks to take const struct kiocb * as their first
argument, allowing IOCB flags such as IOCB_DONTCACHE to propagate
to the filesystem's buffered I/O path.
Ext4 is updated to implement handling of the IOCB_DONTCACHE flag
and advertises support via the FOP_DONTCACHE file operation flag.
Additionally, the i915 driver's shmem write paths are updated to
bypass the legacy write_begin/write_end interface in favor of
directly calling write_iter() with a constructed synchronous kiocb.
Another i915 change replaces a manual write loop with
kernel_write() during GEM shmem object creation.
Cleanups:
- don't duplicate vfs_open() in kernel_file_open()
- proc_fd_getattr(): don't bother with S_ISDIR() check
- fs/ecryptfs: replace snprintf with sysfs_emit in show function
- vfs: Remove unnecessary list_for_each_entry_safe() from
evict_inodes()
- filelock: add new locks_wake_up_waiter() helper
- fs: Remove three arguments from block_write_end()
- VFS: change old_dir and new_dir in struct renamedata to dentrys
- netfs: Remove unused declaration netfs_queue_write_request()
Fixes:
- eventpoll: Fix semi-unbounded recursion
- eventpoll: fix sphinx documentation build warning
- fs/read_write: Fix spelling typo
- fs: annotate data race between poll_schedule_timeout() and
pollwake()
- fs/pipe: set FMODE_NOWAIT in create_pipe_files()
- docs/vfs: update references to i_mutex to i_rwsem
- fs/buffer: remove comment about hard sectorsize
- fs/buffer: remove the min and max limit checks in __getblk_slow()
- fs/libfs: don't assume blocksize <= PAGE_SIZE in
generic_check_addressable
- fs_context: fix parameter name in infofc() macro
- fs: Prevent file descriptor table allocations exceeding INT_MAX"
* tag 'vfs-6.17-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (24 commits)
netfs: Remove unused declaration netfs_queue_write_request()
eventpoll: fix sphinx documentation build warning
ext4: support uncached buffered I/O
mm/pagemap: add write_begin_get_folio() helper function
fs: change write_begin/write_end interface to take struct kiocb *
drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter
drm/i915: Use kernel_write() in shmem object create
eventpoll: Fix semi-unbounded recursion
vfs: Remove unnecessary list_for_each_entry_safe() from evict_inodes()
fs/libfs: don't assume blocksize <= PAGE_SIZE in generic_check_addressable
fs/buffer: remove the min and max limit checks in __getblk_slow()
fs: Prevent file descriptor table allocations exceeding INT_MAX
fs: Remove three arguments from block_write_end()
fs/ecryptfs: replace snprintf with sysfs_emit in show function
fs: annotate suspected data race between poll_schedule_timeout() and pollwake()
docs/vfs: update references to i_mutex to i_rwsem
fs/buffer: remove comment about hard sectorsize
fs_context: fix parameter name in infofc() macro
VFS: change old_dir and new_dir in struct renamedata to dentrys
proc_fd_getattr(): don't bother with S_ISDIR() check
...
The only remaining user of ovl_cleanup() is ovl_cleanup_locked(), so we
no longer need both.
This patch renames ovl_cleanup() to ovl_cleanup_locked() and makes it
static.
ovl_cleanup_unlocked() is renamed to ovl_cleanup().
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-22-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Instead of passing an inode *dir, pass a dentry *parent. This makes the
calling slightly cleaner.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-21-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
Rather than calling ovl_workdir_cleanup() with the dir already locked,
change it to take the dir lock only when needed.
Also change ovl_workdir_cleanup() to take a dentry for the parent rather
than an inode.
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-16-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
ovl currently locks a directory or two and then performs multiple actions
in one or both directories. This is incompatible with proposed changes
which will lock just the dentry of objects being acted on.
This patch moves calls to ovl_create_temp() out of the locked regions and
has it take and release the relevant lock itself.
The lock that was taken before this function was called is now taken
after. This means that any code between where the lock was taken and
ovl_create_temp() is now unlocked. This necessitates the use of
ovl_cleanup_unlocked() and the creation of ovl_lookup_upper_unlocked().
These will be used more widely in future patches.
Now that the file is created before the lock is taken for rename, we
need to ensure the parent wasn't changed before the lock was gained.
ovl_lock_rename_workdir() is changed to optionally receive the dentries
that will be involved in the rename. If either is present but has the
wrong parent, an error is returned.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-4-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
If ovl_copy_up_data() fails the error is not immediately handled but the
code continues on to call ovl_start_write() and lock_rename(),
presumably because both of these locks are needed for the cleanup.
Only then (if the lock was successful) is the error checked.
This makes the code a little hard to follow and could be fragile.
This patch changes to handle the error after the ovl_start_write()
(which cannot fail, so there aren't multiple errors to deail with). A
new ovl_cleanup_unlocked() is created which takes the required directory
lock. This will be used extensively in later patches.
In general we need to check the parent is still correct after taking the
lock (as ovl_copy_up_workdir() does after a successful lock_rename()) so
that is included in ovl_cleanup_unlocked() using new ovl_parent_lock()
and ovl_parent_unlock() calls (it is planned to move this API into VFS code
eventually, though in a slightly different form).
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-2-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Case folding is often applied to subtrees and not on an entire
filesystem.
Disallowing layers from filesystems that support case folding is over
limiting.
Replace the rule that case-folding capable are not allowed as layers
with a rule that case folded directories are not allowed in a merged
directory stack.
Should case folding be enabled on an underlying directory while
overlayfs is mounted the outcome is generally undefined.
Specifically in ovl_lookup(), we check the base underlying directory
and fail with -ESTALE and write a warning to kmsg if an underlying
directory case folding is enabled.
Suggested-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lore.kernel.org/linux-fsdevel/20250520051600.1903319-1-kent.overstreet@linux.dev/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/20250602171702.1941891-1-amir73il@gmail.com
Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Now that we expose struct file_attr as our uapi struct rename all the
internal struct to struct file_kattr to clearly communicate that it is a
kernel internal struct. This is similar to struct mount_{k}attr and
others.
Link: https://lore.kernel.org/20250703-restlaufzeit-baurecht-9ed44552b481@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
all users of 'struct renamedata' have the dentry for the old and new
directories, and often have no use for the inode except to store it in
the renamedata.
This patch changes struct renamedata to hold the dentry, rather than
the inode, for the old and new directories, and changes callers to
match. The names are also changed from a _dir suffix to _parent. This
is consistent with other usage in namei.c and elsewhere.
This results in the removal of several local variables and several
dereferences of ->d_inode at the cost of adding ->d_inode dereferences
to vfs_rename().
Acked-by: Miklos Szeredi <miklos@szeredi.hu>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/174977089072.608730.4244531834577097454@noble.neil.brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
We want to print the name in case of mkdir failure and now we will
get a cryptic (efault) as name.
Fixes: c54b386969a5 ("VFS: Change vfs_mkdir() to return the dentry.")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/20250612072245.2825938-1-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Merge tag 'vfs-6.16-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs directory lookup updates from Christian Brauner:
"This contains cleanups for the lookup_one*() family of helpers.
We expose a set of functions with names containing "lookup_one_len"
and others without the "_len". This difference has nothing to do with
"len". It's rater a historical accident that can be confusing.
The functions without "_len" take a "mnt_idmap" pointer. This is found
in the "vfsmount" and that is an important question when choosing
which to use: do you have a vfsmount, or are you "inside" the
filesystem. A related question is "is permission checking relevant
here?".
nfsd and cachefiles *do* have a vfsmount but *don't* use the non-_len
functions. They pass nop_mnt_idmap and refuse to work on filesystems
which have any other idmap.
This work changes nfsd and cachefile to use the lookup_one family of
functions and to explictily pass &nop_mnt_idmap which is consistent
with all other vfs interfaces used where &nop_mnt_idmap is explicitly
passed.
The remaining uses of the "_one" functions do not require permission
checks so these are renamed to be "_noperm" and the permission
checking is removed.
This series also changes these lookup function to take a qstr instead
of separate name and len. In many cases this simplifies the call"
* tag 'vfs-6.16-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
VFS: change lookup_one_common and lookup_noperm_common to take a qstr
Use try_lookup_noperm() instead of d_hash_and_lookup() outside of VFS
VFS: rename lookup_one_len family to lookup_noperm and remove permission check
cachefiles: Use lookup_one() rather than lookup_one_len()
nfsd: Use lookup_one() rather than lookup_one_len()
VFS: improve interface for lookup_one functions
The ovl_get_verity_xattr() function was never added, only its declaration.
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Fixes: 184996e92e86 ("ovl: Validate verity xattr when resolving lowerdata")
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Alexander Larsson <alexl@redhat.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The family of functions:
lookup_one()
lookup_one_unlocked()
lookup_one_positive_unlocked()
appear designed to be used by external clients of the filesystem rather
than by filesystems acting on themselves as the lookup_one_len family
are used.
They are used by:
btrfs/ioctl - which is a user-space interface rather than an internal
activity
exportfs - i.e. from nfsd or the open_by_handle_at interface
overlayfs - at access the underlying filesystems
smb/server - for file service
They should be used by nfsd (more than just the exportfs path) and
cachefs but aren't.
It would help if the documentation didn't claim they should "not be
called by generic code".
Also the path component name is passed as "name" and "len" which are
(confusingly?) separate by the "base". In some cases the len in simply
"strlen" and so passing a qstr using QSTR() would make the calling
clearer.
Other callers do pass separate name and len which are stored in a
struct. Sometimes these are already stored in a qstr, other times it
easily could be.
So this patch changes these three functions to receive a 'struct qstr *',
and improves the documentation.
QSTR_LEN() is added to make it easy to pass a QSTR containing a known
len.
[brauner@kernel.org: take a struct qstr pointer]
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/r/20250319031545.2999807-2-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
vfs_mkdir() does not guarantee to leave the child dentry hashed or make
it positive on success, and in many such cases the filesystem had to use
a different dentry which it can now return.
This patch changes vfs_mkdir() to return the dentry provided by the
filesystems which is hashed and positive when provided. This reduces
the number of cases where the resulting dentry is not positive to a
handful which don't deserve extra efforts.
The only callers of vfs_mkdir() which are interested in the resulting
inode are in-kernel filesystem clients: cachefiles, nfsd, smb/server.
The only filesystems that don't reliably provide the inode are:
- kernfs, tracefs which these clients are unlikely to be interested in
- cifs in some configurations would need to do a lookup to find the
created inode, but doesn't. cifs cannot be exported via NFS, is
unlikely to be used by cachefiles, and smb/server only has a soft
requirement for the inode, so this is unlikely to be a problem in
practice.
- hostfs, nfs, cifs may need to do a lookup (rarely for NFS) and it is
possible for a race to make that lookup fail. Actual failure
is unlikely and providing callers handle negative dentries graceful
they will fail-safe.
So this patch removes the lookup code in nfsd and smb/server and adjusts
them to fail safe if a negative dentry is provided:
- cache-files already fails safe by restarting the task from the
top - it still does with this change, though it no longer calls
cachefiles_put_directory() as that will crash if the dentry is
negative.
- nfsd reports "Server-fault" which it what it used to do if the lookup
failed. This will never happen on any file-systems that it can actually
export, so this is of no consequence. I removed the fh_update()
call as that is not needed and out-of-place. A subsequent
nfsd_create_setattr() call will call fh_update() when needed.
- smb/server only wants the inode to call ksmbd_smb_inherit_owner()
which updates ->i_uid (without calling notify_change() or similar)
which can be safely skipping on cifs (I hope).
If a different dentry is returned, the first one is put. If necessary
the fact that it is new can be determined by comparing pointers. A new
dentry will certainly have a new pointer (as the old is put after the
new is obtained).
Similarly if an error is returned (via ERR_PTR()) the original dentry is
put.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-7-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Merge tag 'ovl-update-6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs
Pull overlayfs updates from Amir Goldstein:
- Fix a syzbot reported NULL pointer deref with bfs lower layers
- Fix a copy up failure of large file from lower fuse fs
- Followup cleanup of backing_file API from Miklos
- Introduction and use of revert/override_creds_light() helpers, that
were suggested by Christian as a mitigation to cache line bouncing
and false sharing of fields in overlayfs creator_cred long lived
struct cred copy.
- Store up to two backing file references (upper and lower) in an
ovl_file container instead of storing a single backing file in
file->private_data.
This is used to avoid the practice of opening a short lived backing
file for the duration of some file operations and to avoid the
specialized use of FDPUT_FPUT in such occasions, that was getting in
the way of Al's fd_file() conversions.
* tag 'ovl-update-6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs:
ovl: Filter invalid inodes with missing lookup function
ovl: convert ovl_real_fdget() callers to ovl_real_file()
ovl: convert ovl_real_fdget_path() callers to ovl_real_file_path()
ovl: store upper real file in ovl_file struct
ovl: allocate a container struct ovl_file for ovl private context
ovl: do not open non-data lower file for fsync
ovl: Optimize override/revert creds
ovl: pass an explicit reference of creators creds to callers
ovl: use wrapper ovl_revert_creds()
fs/backing-file: Convert to revert/override_creds_light()
cred: Add a light version of override/revert_creds()
backing-file: clean up the API
ovl: properly handle large files in ovl_security_fileattr
Instead of using ->private_data to point at realfile directly, so
that we can add more context per ovl open file.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Commit 8a924db2d7b5 ("fs: Pass AT_GETATTR_NOSEC flag to getattr interface
function")' introduced the AT_GETATTR_NOSEC flag to ensure that the
call paths only call vfs_getattr_nosec if it is set instead of vfs_getattr.
Now, simplify the getattr interface functions of filesystems where the flag
AT_GETATTR_NOSEC is checked.
There is only a single caller of inode_operations getattr function and it
is located in fs/stat.c in vfs_getattr_nosec. The caller there is the only
one from which the AT_GETATTR_NOSEC flag is passed from.
Two filesystems are checking this flag in .getattr and the flag is always
passed to them unconditionally from only vfs_getattr_nosec:
- ecryptfs: Simplify by always calling vfs_getattr_nosec in
ecryptfs_getattr. From there the flag is passed to no other
function and this function is not called otherwise.
- overlayfs: Simplify by always calling vfs_getattr_nosec in
ovl_getattr. From there the flag is passed to no other
function and this function is not called otherwise.
The query_flags in vfs_getattr_nosec will mask-out AT_GETATTR_NOSEC from
any caller using AT_STATX_SYNC_TYPE as mask so that the flag is not
important inside this function. Also, since no filesystem is checking the
flag anymore, remove the flag entirely now, including the BUG_ON check that
never triggered.
The net change of the changes here combined with the original commit is
that ecryptfs and overlayfs do not call vfs_getattr but only
vfs_getattr_nosec.
Fixes: 8a924db2d7b5 ("fs: Pass AT_GETATTR_NOSEC flag to getattr interface function")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Closes: https://lore.kernel.org/linux-fsdevel/20241101011724.GN1350452@ZenIV/T/#u
Cc: Tyler Hicks <code@tyhicks.com>
Cc: ecryptfs@vger.kernel.org
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: linux-unionfs@vger.kernel.org
Cc: Christian Brauner <brauner@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Introduce ovl_revert_creds() wrapper of revert_creds() to
match callers of ovl_override_creds().
Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Combine inode creation with opening a file.
There are six separate objects that are being set up: the backing inode,
dentry and file, and the overlay inode, dentry and file. Cleanup in case
of an error is a bit of a challenge and is difficult to test, so careful
review is needed.
All tmpfile testcases except generic/509 now run/pass, and no regressions
are observed with full xfstests.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
An opaque directory cannot have xwhiteouts, so instead of marking an
xwhiteouts directory with a new xattr, overload overlay.opaque xattr
for marking both opaque dir ('y') and xwhiteouts dir ('x').
This is more efficient as the overlay.opaque xattr is checked during
lookup of directory anyway.
This also prevents unnecessary checking the xattr when reading a
directory without xwhiteouts, i.e. most of the time.
Note that the xwhiteouts marker is not checked on the upper layer and
on the last layer in lowerstack, where xwhiteouts are not expected.
Fixes: bc8df7a3dc03 ("ovl: Add an alternative type of whiteout")
Cc: <stable@vger.kernel.org> # v6.7
Reviewed-by: Alexander Larsson <alexl@redhat.com>
Tested-by: Alexander Larsson <alexl@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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Merge tag 'vfs-6.8.rw' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs rw updates from Christian Brauner:
"This contains updates from Amir for read-write backing file helpers
for stacking filesystems such as overlayfs:
- Fanotify is currently in the process of introducing pre content
events. Roughly, a new permission event will be added indicating
that it is safe to write to the file being accessed. These events
are used by hierarchical storage managers to e.g., fill the content
of files on first access.
During that work we noticed that our current permission checking is
inconsistent in rw_verify_area() and remap_verify_area().
Especially in the splice code permission checking is done multiple
times. For example, one time for the whole range and then again for
partial ranges inside the iterator.
In addition, we mostly do permission checking before we call
file_start_write() except for a few places where we call it after.
For pre-content events we need such permission checking to be done
before file_start_write(). So this is a nice reason to clean this
all up.
After this series, all permission checking is done before
file_start_write().
As part of this cleanup we also massaged the splice code a bit. We
got rid of a few helpers because we are alredy drowning in special
read-write helpers. We also cleaned up the return types for splice
helpers.
- Introduce generic read-write helpers for backing files. This lifts
some overlayfs code to common code so it can be used by the FUSE
passthrough work coming in over the next cycles. Make Amir and
Miklos the maintainers for this new subsystem of the vfs"
* tag 'vfs-6.8.rw' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits)
fs: fix __sb_write_started() kerneldoc formatting
fs: factor out backing_file_mmap() helper
fs: factor out backing_file_splice_{read,write}() helpers
fs: factor out backing_file_{read,write}_iter() helpers
fs: prepare for stackable filesystems backing file helpers
fsnotify: optionally pass access range in file permission hooks
fsnotify: assert that file_start_write() is not held in permission hooks
fsnotify: split fsnotify_perm() into two hooks
fs: use splice_copy_file_range() inline helper
splice: return type ssize_t from all helpers
fs: use do_splice_direct() for nfsd/ksmbd server-side-copy
fs: move file_start_write() into direct_splice_actor()
fs: fork splice_file_range() from do_splice_direct()
fs: create {sb,file}_write_not_started() helpers
fs: create file_write_started() helper
fs: create __sb_write_started() helper
fs: move kiocb_start_write() into vfs_iocb_iter_write()
fs: move permission hook out of do_iter_read()
fs: move permission hook out of do_iter_write()
fs: move file_start_write() into vfs_iter_write()
...
When vfs_getattr_nosec() calls a filesystem's getattr interface function
then the 'nosec' should propagate into this function so that
vfs_getattr_nosec() can again be called from the filesystem's gettattr
rather than vfs_getattr(). The latter would add unnecessary security
checks that the initial vfs_getattr_nosec() call wanted to avoid.
Therefore, introduce the getattr flag GETATTR_NOSEC and allow to pass
with the new getattr_flags parameter to the getattr interface function.
In overlayfs and ecryptfs use this flag to determine which one of the
two functions to call.
In a recent code change introduced to IMA vfs_getattr_nosec() ended up
calling vfs_getattr() in overlayfs, which in turn called
security_inode_getattr() on an exiting process that did not have
current->fs set anymore, which then caused a kernel NULL pointer
dereference. With this change the call to security_inode_getattr() can
be avoided, thus avoiding the NULL pointer dereference.
Reported-by: <syzbot+a67fc5321ffb4b311c98@syzkaller.appspotmail.com>
Fixes: db1d1e8b9867 ("IMA: use vfs_getattr_nosec to get the i_version")
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Tyler Hicks <code@tyhicks.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Suggested-by: Christian Brauner <brauner@kernel.org>
Co-developed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Link: https://lore.kernel.org/r/20231002125733.1251467-1-stefanb@linux.vnet.ibm.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
An xattr whiteout (called "xwhiteout" in the code) is a reguar file of
zero size with the "overlay.whiteout" xattr set. A file like this in a
directory with the "overlay.whiteouts" xattrs set will be treated the
same way as a regular whiteout.
The "overlay.whiteouts" directory xattr is used in order to
efficiently handle overlay checks in readdir(), as we only need to
checks xattrs in affected directories.
The advantage of this kind of whiteout is that they can be escaped
using the standard overlay xattr escaping mechanism. So, a file with a
"overlay.overlay.whiteout" xattr would be unescaped to
"overlay.whiteout", which could then be consumed by another overlayfs
as a whiteout.
Overlayfs itself doesn't create whiteouts like this, but a userspace
mechanism could use this alternative mechanism to convert images that
may contain whiteouts to be used with overlayfs.
To work as a whiteout for both regular overlayfs mounts as well as
userxattr mounts both the "user.overlay.whiteout*" and the
"trusted.overlay.whiteout*" xattrs will need to be created.
Signed-off-by: Alexander Larsson <alexl@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
There are cases where you want to use an overlayfs mount as a lowerdir
for another overlayfs mount. For example, if the system rootfs is on
overlayfs due to composefs, or to make it volatile (via tmps), then
you cannot currently store a lowerdir on the rootfs. This means you
can't e.g. store on the rootfs a prepared container image for use
using overlayfs.
To work around this, we introduce an escapment mechanism for overlayfs
xattrs. Whenever the lower/upper dir has a xattr named
"overlay.overlay.XYZ", we list it as "overlay.XYZ" in listxattrs, and
when the user calls getxattr or setxattr on "overlay.XYZ", we apply to
"overlay.overlay.XYZ" in the backing directories.
This allows storing any kind of overlay xattrs in a overlayfs mount
that can be used as a lowerdir in another mount. It is possible to
stack this mechanism multiple times, such that
"overlay.overlay.overlay.XYZ" will survive two levels of overlay mounts,
however this is not all that useful in practice because of stack depth
limitations of overlayfs mounts.
Note: These escaped xattrs are copied to upper during copy-up.
Signed-off-by: Alexander Larsson <alexl@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
These match the ones for e.g. XATTR_TRUSTED_PREFIX_LEN.
Signed-off-by: Alexander Larsson <alexl@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
This moves the code from super.c and inode.c, and makes ovl_xattr_get/set()
static.
This is in preparation for doing more work on xattrs support.
Signed-off-by: Alexander Larsson <alexl@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
When lower fs is a nested overlayfs, calling encode_fh() on a lower
directory dentry may trigger copy up and take sb_writers on the upper fs
of the lower nested overlayfs.
The lower nested overlayfs may have the same upper fs as this overlayfs,
so nested sb_writers lock is illegal.
Move all the callers that encode lower fh to before ovl_want_write().
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
ovl_get_write_access() gets write access to upper mnt without taking
freeze protection on upper sb and ovl_start_write() only takes freeze
protection on upper sb.
These helpers will be used to breakup the large ovl_want_write() scope
during copy up into finer grained freeze protection scopes.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
