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1065 commits

Author SHA1 Message Date
Linus Torvalds
57fcb7d930 vfs-6.17-rc1.fileattr
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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
2025-07-28 15:24:14 -07:00
Linus Torvalds
934600daa7 vfs-6.17-rc1.ovl
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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.
  ...
2025-07-28 12:20:06 -07:00
Linus Torvalds
7879d7aff0 vfs-6.17-rc1.misc
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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
  ...
2025-07-28 11:22:56 -07:00
Linus Torvalds
11fe69fbd5 Current exclusion rules for ->d_flags stores are rather unpleasant.
The basic rules are simple:
 	* stores to dentry->d_flags are OK under dentry->d_lock.
 	* stores to dentry->d_flags are OK in the dentry constructor, before
 becomes potentially visible to other threads.
 Unfortunately, there's a couple of exceptions to that, and that's where the
 headache comes from.
 
 	Main PITA comes from d_set_d_op(); that primitive sets ->d_op
 of dentry and adjusts the flags that correspond to presence of individual
 methods.  It's very easy to misuse; existing uses _are_ safe, but proof
 of correctness is brittle.
 
 	Use in __d_alloc() is safe (we are within a constructor), but we
 might as well precalculate the initial value of ->d_flags when we set
 the default ->d_op for given superblock and set ->d_flags directly
 instead of messing with that helper.
 
 	The reasons why other uses are safe are bloody convoluted; I'm not going
 to reproduce it here.  See https://lore.kernel.org/all/20250224010624.GT1977892@ZenIV/
 for gory details, if you care.  The critical part is using d_set_d_op() only
 just prior to d_splice_alias(), which makes a combination of d_splice_alias()
 with setting ->d_op, etc. a natural replacement primitive.  Better yet, if
 we go that way, it's easy to take setting ->d_op and modifying ->d_flags
 under ->d_lock, which eliminates the headache as far as ->d_flags exclusion
 rules are concerned.  Other exceptions are minor and easy to deal with.
 
 	What this series does:
 * d_set_d_op() is no longer available; new primitive (d_splice_alias_ops())
 is provided, equivalent to combination of d_set_d_op() and d_splice_alias().
 * new field of struct super_block - ->s_d_flags.  Default value of ->d_flags
 to be used when allocating dentries on this filesystem.
 * new primitive for setting ->s_d_op: set_default_d_op().  Replaces stores
 to ->s_d_op at mount time.  All in-tree filesystems converted; out-of-tree
 ones will get caught by compiler (->s_d_op is renamed, so stores to it will
 be caught).  ->s_d_flags is set by the same primitive to match the ->s_d_op.
 * a lot of filesystems had ->s_d_op->d_delete equal to always_delete_dentry;
 that is equivalent to setting DCACHE_DONTCACHE in ->d_flags, so such filesystems
 can bloody well set that bit in ->s_d_flags and drop ->d_delete() from
 dentry_operations.  In quite a few cases that results in empty dentry_operations,
 which means that we can get rid of those.
 * kill simple_dentry_operations - not needed anymore.
 * massage d_alloc_parallel() to get rid of the other exception wrt ->d_flags
 stores - we can set DCACHE_PAR_LOOKUP as soon as we allocate the new dentry;
 no need to delay that until we commit to using the sucker.
 
 As the result, ->d_flags stores are all either under ->d_lock or done before
 the dentry becomes visible in any shared data structures.
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Merge tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull dentry d_flags updates from Al Viro:
 "The current exclusion rules for dentry->d_flags stores are rather
  unpleasant. The basic rules are simple:

   - stores to dentry->d_flags are OK under dentry->d_lock

   - stores to dentry->d_flags are OK in the dentry constructor, before
     becomes potentially visible to other threads

  Unfortunately, there's a couple of exceptions to that, and that's
  where the headache comes from.

  The main PITA comes from d_set_d_op(); that primitive sets ->d_op of
  dentry and adjusts the flags that correspond to presence of individual
  methods. It's very easy to misuse; existing uses _are_ safe, but proof
  of correctness is brittle.

  Use in __d_alloc() is safe (we are within a constructor), but we might
  as well precalculate the initial value of 'd_flags' when we set the
  default ->d_op for given superblock and set 'd_flags' directly instead
  of messing with that helper.

  The reasons why other uses are safe are bloody convoluted; I'm not
  going to reproduce it here. See [1] for gory details, if you care. The
  critical part is using d_set_d_op() only just prior to
  d_splice_alias(), which makes a combination of d_splice_alias() with
  setting ->d_op, etc a natural replacement primitive.

  Better yet, if we go that way, it's easy to take setting ->d_op and
  modifying 'd_flags' under ->d_lock, which eliminates the headache as
  far as 'd_flags' exclusion rules are concerned. Other exceptions are
  minor and easy to deal with.

  What this series does:

   - d_set_d_op() is no longer available; instead a new primitive
     (d_splice_alias_ops()) is provided, equivalent to combination of
     d_set_d_op() and d_splice_alias().

   - new field of struct super_block - 's_d_flags'. This sets the
     default value of 'd_flags' to be used when allocating dentries on
     this filesystem.

   - new primitive for setting 's_d_op': set_default_d_op(). This
     replaces stores to 's_d_op' at mount time.

     All in-tree filesystems converted; out-of-tree ones will get caught
     by the compiler ('s_d_op' is renamed, so stores to it will be
     caught). 's_d_flags' is set by the same primitive to match the
     's_d_op'.

   - a lot of filesystems had sb->s_d_op->d_delete equal to
     always_delete_dentry; that is equivalent to setting
     DCACHE_DONTCACHE in 'd_flags', so such filesystems can bloody well
     set that bit in 's_d_flags' and drop 'd_delete()' from
     dentry_operations.

     In quite a few cases that results in empty dentry_operations, which
     means that we can get rid of those.

   - kill simple_dentry_operations - not needed anymore

   - massage d_alloc_parallel() to get rid of the other exception wrt
     'd_flags' stores - we can set DCACHE_PAR_LOOKUP as soon as we
     allocate the new dentry; no need to delay that until we commit to
     using the sucker.

  As the result, 'd_flags' stores are all either under ->d_lock or done
  before the dentry becomes visible in any shared data structures"

Link: https://lore.kernel.org/all/20250224010624.GT1977892@ZenIV/ [1]

* tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (21 commits)
  configfs: use DCACHE_DONTCACHE
  debugfs: use DCACHE_DONTCACHE
  efivarfs: use DCACHE_DONTCACHE instead of always_delete_dentry()
  9p: don't bother with always_delete_dentry
  ramfs, hugetlbfs, mqueue: set DCACHE_DONTCACHE
  kill simple_dentry_operations
  devpts, sunrpc, hostfs: don't bother with ->d_op
  shmem: no dentry retention past the refcount reaching zero
  d_alloc_parallel(): set DCACHE_PAR_LOOKUP earlier
  make d_set_d_op() static
  simple_lookup(): just set DCACHE_DONTCACHE
  tracefs: Add d_delete to remove negative dentries
  set_default_d_op(): calculate the matching value for ->d_flags
  correct the set of flags forbidden at d_set_d_op() time
  split d_flags calculation out of d_set_d_op()
  new helper: set_default_d_op()
  fuse: no need for special dentry_operations for root dentry
  switch procfs from d_set_d_op() to d_splice_alias_ops()
  new helper: d_splice_alias_ops()
  procfs: kill ->proc_dops
  ...
2025-07-28 09:17:57 -07:00
Antonio Quartulli
672820a070
ovl: properly print correct variable
In case of ovl_lookup_temp() failure, we currently print `err`
which is actually not initialized at all.

Instead, properly print PTR_ERR(whiteout) which is where the
actual error really is.

Address-Coverity-ID: 1647983 ("Uninitialized variables  (UNINIT)")
Fixes: 8afa0a7367 ("ovl: narrow locking in ovl_whiteout()")
Signed-off-by: Antonio Quartulli <antonio@mandelbit.com>
Link: https://lore.kernel.org/20250721203821.7812-1-antonio@mandelbit.com
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-25 10:20:36 +02:00
NeilBrown
fe4d3360f9
ovl: rename ovl_cleanup_unlocked() to ovl_cleanup()
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>
2025-07-18 11:10:43 +02:00
NeilBrown
ee37c3cfc5
ovl: change ovl_create_real() to receive dentry parent
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>
2025-07-18 11:10:43 +02:00
NeilBrown
09d56cc88c
ovl: narrow locking in ovl_check_rename_whiteout()
ovl_check_rename_whiteout() now only holds the directory lock when
needed, and takes it again if necessary.

This makes way for future changes where locks are taken on individual
dentries rather than the whole directory.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-20-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:43 +02:00
NeilBrown
8afa0a7367
ovl: narrow locking in ovl_whiteout()
ovl_whiteout() relies on the workdir i_rwsem to provide exclusive access
to ofs->whiteout which it manipulates.  Rather than depending on this,
add a new mutex, "whiteout_lock" to explicitly provide the required
locking.  Use guard(mutex) for this so that we can return without
needing to explicitly unlock.

Then take the lock on workdir only when needed - to lookup the temp name
and to do the whiteout or link.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-19-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:42 +02:00
NeilBrown
2fa14cf2dc
ovl: change ovl_cleanup_and_whiteout() to take rename lock as needed
Rather than locking the directory(s) before calling
ovl_cleanup_and_whiteout(), change it (and ovl_whiteout()) to do the
locking, so the locking can be fine grained as will be needed for
proposed locking changes.

Sometimes this is called to whiteout something in the index dir, in
which case only that dir must be locked.  In one case it is called on
something in an upperdir, so two directories must be locked.  We use
ovl_lock_rename_workdir() for this and remove the restriction that
upperdir cannot be indexdir - because now sometimes it is.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-18-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:42 +02:00
NeilBrown
c69566b1d1
ovl: narrow locking on ovl_remove_and_whiteout()
This code:
  performs a lookup_upper
  creates a whiteout object
  renames the whiteout over the result of the lookup

The create and the rename must be locked separately for proposed
directory locking changes.  This patch takes a first step of moving the
lookup out of the locked region.  A subsequent patch will separate the
create from the rename.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-17-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:42 +02:00
NeilBrown
241062ae5d
ovl: change ovl_workdir_cleanup() to take dir lock as needed.
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>
2025-07-18 11:10:42 +02:00
NeilBrown
a45ee87ded
ovl: narrow locking in ovl_workdir_cleanup_recurse()
Only take the dir lock when needed, rather than for the whole loop.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-15-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:42 +02:00
NeilBrown
d56c6feb69
ovl: narrow locking in ovl_indexdir_cleanup()
Instead of taking the directory lock for the whole cleanup, only take it
when needed.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-14-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:42 +02:00
NeilBrown
61eb7fec9e
ovl: narrow locking in ovl_workdir_create()
In ovl_workdir_create() don't hold the dir lock for the whole time, but
only take it when needed.

It now gets taken separately for ovl_workdir_cleanup().  A subsequent
patch will move the locking into that function.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-13-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:42 +02:00
NeilBrown
8290fb412d
ovl: narrow locking in ovl_cleanup_index()
ovl_cleanup_index() takes a lock on the directory and then does a lookup
and possibly one of two different cleanups.
This patch narrows the locking to use the _unlocked() versions of the
lookup and one cleanup, and just takes the lock for the other cleanup.

A subsequent patch will take the lock into the cleanup.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-12-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:41 +02:00
NeilBrown
7dfb0722ad
ovl: narrow locking in ovl_cleanup_whiteouts()
Rather than lock the directory for the whole operation, use
ovl_lookup_upper_unlocked() and ovl_cleanup_unlocked() to take the lock
only when needed.

This makes way for future changes where locks are taken on individual
dentries rather than the whole directory.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-11-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:41 +02:00
NeilBrown
05468498cd
ovl: narrow locking in ovl_rename()
Drop the rename lock immediately after the rename, and use
ovl_cleanup_unlocked() for cleanup.

This makes way for future changes where locks are taken on individual
dentries rather than the whole directory.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-10-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:41 +02:00
NeilBrown
76342c9eb8
ovl: simplify gotos in ovl_rename()
Rather than having three separate goto label: out_unlock, out_dput_old,
and out_dput, make use of that fact that dput() happily accepts a NULL
pointer to reduce this to just one goto label: out_unlock.

olddentry and newdentry are initialised to NULL and only set once a
value dentry is found.  They are then dput() late in the function.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-9-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:41 +02:00
NeilBrown
e460bc4d01
ovl: narrow locking in ovl_create_over_whiteout()
Unlock the parents immediately after the rename, and use
ovl_cleanup_unlocked() for cleanup, which takes a separate lock.

This makes way for future changes where locks are taken on individual
dentries rather than the whole directory.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-8-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:41 +02:00
NeilBrown
4f622bd9f3
ovl: narrow locking in ovl_clear_empty()
Drop the locks immediately after rename, and use a separate lock for
cleanup.

This makes way for future changes where locks are taken on individual
dentries rather than the whole directory.

Note that ovl_cleanup_whiteouts() operates on "upper", a child of
"upperdir" and does not require upperdir or workdir to be locked.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-7-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:41 +02:00
NeilBrown
a07052e07b
ovl: narrow locking in ovl_create_upper()
Drop the directory lock immediately after the ovl_create_real() call and
take a separate lock later for cleanup in ovl_cleanup_unlocked() - if
needed.

This makes way for future changes where locks are taken on individual
dentries rather than the whole directory.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-6-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:41 +02:00
NeilBrown
a735bdf0b7
ovl: narrow the locked region in ovl_copy_up_workdir()
In ovl_copy_up_workdir() unlock immediately after the rename.  There is
nothing else in the function that needs the lock.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-5-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:40 +02:00
NeilBrown
d2c995581c
ovl: Call ovl_create_temp() without lock held.
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>
2025-07-18 11:10:40 +02:00
NeilBrown
c4f8f862b3
ovl: change ovl_create_index() to take dir locks
ovl_copy_up_workdir() currently take a rename lock on two directories,
then use the lock to both create a file in one directory, perform a
rename, and possibly unlink the file for cleanup.  This is incompatible
with proposed changes which will lock just the dentry of objects being
acted on.

This patch moves the call to ovl_create_index() earlier in
ovl_copy_up_workdir() to before the lock is taken.

ovl_create_index() then takes the required lock only when needed.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-3-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:40 +02:00
NeilBrown
9d23967b18
ovl: simplify an error path in ovl_copy_up_workdir()
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>
2025-07-18 11:10:40 +02:00
Amir Goldstein
083957f961
ovl: support layers on case-folding capable filesystems
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>
2025-07-18 11:09:33 +02:00
Amir Goldstein
3ec2529eca
ovl: remove unneeded non-const conversion
file_user_path() now takes a const file ptr.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/20250607115304.2521155-3-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:09:33 +02:00
Christian Brauner
ca115d7e75
tree-wide: s/struct fileattr/struct file_kattr/g
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>
2025-07-04 16:14:39 +02:00
Andrey Albershteyn
474b155adf
fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP
Future patches will add new syscalls which use these functions. As
this interface won't be used for ioctls only, the EOPNOSUPP is more
appropriate return code.

This patch converts return code from ENOIOCTLCMD to EOPNOSUPP for
vfs_fileattr_get and vfs_fileattr_set. To save old behavior translate
EOPNOSUPP back for current users - overlayfs, encryptfs and fs/ioctl.c.

Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
Link: https://lore.kernel.org/20250630-xattrat-syscall-v6-4-c4e3bc35227b@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-02 14:29:10 +02:00
Linus Torvalds
fe78e02600 vfs-6.16-rc3.fixes
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Merge tag 'vfs-6.16-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - Fix a regression in overlayfs caused by reworking the lookup_one*()
   set of helpers

 - Make sure that the name of the dentry is printed in overlayfs'
   mkdir() helper

 - Add missing iocb values to TRACE_IOCB_STRINGS define

 - Unlock the superblock during iterate_supers_type(). This was an
   accidental internal api change

 - Drop a misleading assert in file_seek_cur_needs_f_lock() helper

 - Never refuse to return PIDFD_GET_INGO when parent pid is zero

   That can trivially happen in container scenarios where the parent
   process might be located in an ancestor pid namespace

 - Don't revalidate in try_lookup_noperm() as that causes regression for
   filesystems such as cifs

 - Fix simple_xattr_list() and reset the err variable after
   security_inode_listsecurity() got called so as not to confuse
   userspace about the length of the xattr

* tag 'vfs-6.16-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: drop assert in file_seek_cur_needs_f_lock
  fs: unlock the superblock during iterate_supers_type
  ovl: fix debug print in case of mkdir error
  VFS: change try_lookup_noperm() to skip revalidation
  fs: add missing values to TRACE_IOCB_STRINGS
  fs/xattr.c: fix simple_xattr_list()
  ovl: fix regression caused by lookup helpers API changes
  pidfs: never refuse ppid == 0 in PIDFD_GET_INFO
2025-06-16 08:18:43 -07:00
NeilBrown
bc9241367a
VFS: change old_dir and new_dir in struct renamedata to dentrys
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>
2025-06-16 16:30:45 +02:00
Amir Goldstein
527c88d839
ovl: fix debug print in case of mkdir error
We want to print the name in case of mkdir failure and now we will
get a cryptic (efault) as name.

Fixes: c54b386969 ("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>
2025-06-12 14:25:24 +02:00
Al Viro
05fb0e6664 new helper: set_default_d_op()
... to be used instead of manually assigning to ->s_d_op.
All in-tree filesystem converted (and field itself is renamed,
so any out-of-tree ones in need of conversion will be caught
by compiler).

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-06-10 22:21:16 -04:00
Linus Torvalds
28fb80f089 overlayfs update for 6.16
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Merge tag 'ovl-update-v2-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs

Pull overlayfs update from Miklos Szeredi:

 - Fix a regression in getting the path of an open file (e.g. in
   /proc/PID/maps) for a nested overlayfs setup (André Almeida)

 - Support data-only layers and verity in a user namespace (unprivileged
   composefs use case)

 - Fix a gcc warning (Kees)

 - Cleanups

* tag 'ovl-update-v2-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs:
  ovl: Annotate struct ovl_entry with __counted_by()
  ovl: Replace offsetof() with struct_size() in ovl_stack_free()
  ovl: Replace offsetof() with struct_size() in ovl_cache_entry_new()
  ovl: Check for NULL d_inode() in ovl_dentry_upper()
  ovl: Use str_on_off() helper in ovl_show_options()
  ovl: don't require "metacopy=on" for "verity"
  ovl: relax redirect/metacopy requirements for lower -> data redirect
  ovl: make redirect/metacopy rejection consistent
  ovl: Fix nested backing file paths
2025-06-06 17:54:09 -07:00
Amir Goldstein
714d02b419
ovl: fix regression caused by lookup helpers API changes
The lookup helpers API was changed by merge of vfs-6.16-rc1.async.dir to
pass a non-const qstr pointer argument to lookup_one*() helpers.

All of the callers of this API were changed to pass a pointer to temp
copy of qstr, except overlays that was passing a const pointer to
dentry->d_name that was changed to pass a non-const copy instead
when doing a lookup in lower layer which is not the fs of said dentry.

This wrong use of the API caused a regression in fstest overlay/012.

Fix the regression by making a non-const copy of dentry->d_name prior
to calling the lookup API, but the API should be fixed to not allow this
class of bugs.

Cc: NeilBrown <neilb@suse.de>
Fixes: 5741909697 ("VFS: improve interface for lookup_one functions")
Fixes: 390e34bc14 ("VFS: change lookup_one_common and lookup_noperm_common to take a qstr")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/20250605101530.2336320-1-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-06-05 13:17:08 +02:00
Linus Torvalds
181d8e399f vfs-6.16-rc1.misc
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Merge tag 'vfs-6.16-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:

   - Use folios for symlinks in the page cache

     FUSE already uses folios for its symlinks. Mirror that conversion
     in the generic code and the NFS code. That lets us get rid of a few
     folio->page->folio conversions in this path, and some of the few
     remaining users of read_cache_page() / read_mapping_page()

   - Try and make a few filesystem operations killable on the VFS
     inode->i_mutex level

   - Add sysctl vfs_cache_pressure_denom for bulk file operations

     Some workloads need to preserve more dentries than we currently
     allow through out sysctl interface

     A HDFS servers with 12 HDDs per server, on a HDFS datanode startup
     involves scanning all files and caching their metadata (including
     dentries and inodes) in memory. Each HDD contains approximately 2
     million files, resulting in a total of ~20 million cached dentries
     after initialization

     To minimize dentry reclamation, they set vfs_cache_pressure to 1.
     Despite this configuration, memory pressure conditions can still
     trigger reclamation of up to 50% of cached dentries, reducing the
     cache from 20 million to approximately 10 million entries. During
     the subsequent cache rebuild period, any HDFS datanode restart
     operation incurs substantial latency penalties until full cache
     recovery completes

     To maintain service stability, more dentries need to be preserved
     during memory reclamation. The current minimum reclaim ratio (1/100
     of total dentries) remains too aggressive for such workload. This
     patch introduces vfs_cache_pressure_denom for more granular cache
     pressure control

     The configuration [vfs_cache_pressure=1,
     vfs_cache_pressure_denom=10000] effectively maintains the full 20
     million dentry cache under memory pressure, preventing datanode
     restart performance degradation

   - Avoid some jumps in inode_permission() using likely()/unlikely()

   - Avid a memory access which is most likely a cache miss when
     descending into devcgroup_inode_permission()

   - Add fastpath predicts for stat() and fdput()

   - Anonymous inodes currently don't come with a proper mode causing
     issues in the kernel when we want to add useful VFS debug assert.
     Fix that by giving them a proper mode and masking it off when we
     report it to userspace which relies on them not having any mode

   - Anonymous inodes currently allow to change inode attributes because
     the VFS falls back to simple_setattr() if i_op->setattr isn't
     implemented. This means the ownership and mode for every single
     user of anon_inode_inode can be changed. Block that as it's either
     useless or actively harmful. If specific ownership is needed the
     respective subsystem should allocate anonymous inodes from their
     own private superblock

   - Raise SB_I_NODEV and SB_I_NOEXEC on the anonymous inode superblock

   - Add proper tests for anonymous inode behavior

   - Make it easy to detect proper anonymous inodes and to ensure that
     we can detect them in codepaths such as readahead()

  Cleanups:

   - Port pidfs to the new anon_inode_{g,s}etattr() helpers

   - Try to remove the uselib() system call

   - Add unlikely branch hint return path for poll

   - Add unlikely branch hint on return path for core_sys_select

   - Don't allow signals to interrupt getdents copying for fuse

   - Provide a size hint to dir_context for during readdir()

   - Use writeback_iter directly in mpage_writepages

   - Update compression and mtime descriptions in initramfs
     documentation

   - Update main netfs API document

   - Remove useless plus one in super_cache_scan()

   - Remove unnecessary NULL-check guards during setns()

   - Add separate separate {get,put}_cgroup_ns no-op cases

  Fixes:

   - Fix typo in root= kernel parameter description

   - Use KERN_INFO for infof()|info_plog()|infofc()

   - Correct comments of fs_validate_description()

   - Mark an unlikely if condition with unlikely() in
     vfs_parse_monolithic_sep()

   - Delete macro fsparam_u32hex()

   - Remove unused and problematic validate_constant_table()

   - Fix potential unsigned integer underflow in fs_name()

   - Make file-nr output the total allocated file handles"

* tag 'vfs-6.16-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (43 commits)
  fs: Pass a folio to page_put_link()
  nfs: Use a folio in nfs_get_link()
  fs: Convert __page_get_link() to use a folio
  fs/read_write: make default_llseek() killable
  fs/open: make do_truncate() killable
  fs/open: make chmod_common() and chown_common() killable
  include/linux/fs.h: add inode_lock_killable()
  readdir: supply dir_context.count as readdir buffer size hint
  vfs: Add sysctl vfs_cache_pressure_denom for bulk file operations
  fuse: don't allow signals to interrupt getdents copying
  Documentation: fix typo in root= kernel parameter description
  include/cgroup: separate {get,put}_cgroup_ns no-op case
  kernel/nsproxy: remove unnecessary guards
  fs: use writeback_iter directly in mpage_writepages
  fs: remove useless plus one in super_cache_scan()
  fs: add S_ANON_INODE
  fs: remove uselib() system call
  device_cgroup: avoid access to ->i_rdev in the common case in devcgroup_inode_permission()
  fs/fs_parse: Remove unused and problematic validate_constant_table()
  fs: touch up predicts in inode_permission()
  ...
2025-05-26 09:02:39 -07:00
Linus Torvalds
6d5b940e1e vfs-6.16-rc1.async.dir
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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
2025-05-26 08:02:43 -07:00
Miklos Szeredi
e0410e956b
readdir: supply dir_context.count as readdir buffer size hint
This is a preparation for large readdir buffers in fuse.

Simply setting the fuse buffer size to the userspace buffer size should
work, the record sizes are similar (fuse's is slightly larger than libc's,
so no overflow should ever happen).

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Jaco Kroon <jaco@uls.co.za>
Link: https://lore.kernel.org/20250513151012.1476536-1-mszeredi@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-05-15 11:26:05 +02:00
Thorsten Blum
6f9ccdad0f ovl: Annotate struct ovl_entry with __counted_by()
Add the __counted_by() compiler attribute to the flexible array member
'__lowerstack' to improve access bounds-checking via CONFIG_UBSAN_BOUNDS
and CONFIG_FORTIFY_SOURCE.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-05-05 12:49:20 +02:00
Thorsten Blum
7314166ee7 ovl: Replace offsetof() with struct_size() in ovl_stack_free()
Compared to offsetof(), struct_size() provides additional compile-time
checks for structs with flexible arrays (e.g., __must_be_array()).

No functional changes intended.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-05-05 12:47:57 +02:00
Thorsten Blum
5aaf6a8cc3 ovl: Replace offsetof() with struct_size() in ovl_cache_entry_new()
Compared to offsetof(), struct_size() provides additional compile-time
checks for structs with flexible arrays (e.g., __must_be_array()).

No functional changes intended.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-05-05 12:47:30 +02:00
Kees Cook
8a39f1c870 ovl: Check for NULL d_inode() in ovl_dentry_upper()
In ovl_path_type() and ovl_is_metacopy_dentry() GCC notices that it is
possible for OVL_E() to return NULL (which implies that d_inode(dentry)
may be NULL). This would result in out of bounds reads via container_of(),
seen with GCC 15's -Warray-bounds -fdiagnostics-details. For example:

In file included from arch/x86/include/generated/asm/rwonce.h:1,
                 from include/linux/compiler.h:339,
                 from include/linux/export.h:5,
                 from include/linux/linkage.h:7,
                 from include/linux/fs.h:5,
                 from fs/overlayfs/util.c:7:
In function 'ovl_upperdentry_dereference',
    inlined from 'ovl_dentry_upper' at ../fs/overlayfs/util.c:305:9,
    inlined from 'ovl_path_type' at ../fs/overlayfs/util.c:216:6:
include/asm-generic/rwonce.h:44:26: error: array subscript 0 is outside array bounds of 'struct inode[7486503276667837]' [-Werror=array-bounds=]
   44 | #define __READ_ONCE(x)  (*(const volatile __unqual_scalar_typeof(x) *)&(x))
      |                         ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:50:9: note: in expansion of macro '__READ_ONCE'
   50 |         __READ_ONCE(x);                                                 \
      |         ^~~~~~~~~~~
fs/overlayfs/ovl_entry.h:195:16: note: in expansion of macro 'READ_ONCE'
  195 |         return READ_ONCE(oi->__upperdentry);
      |                ^~~~~~~~~
  'ovl_path_type': event 1
  185 |         return inode ? OVL_I(inode)->oe : NULL;
  'ovl_path_type': event 2

Avoid this by allowing ovl_dentry_upper() to return NULL if d_inode() is
NULL, as that means the problematic dereferencing can never be reached.
Note that this fixes the over-eager compiler warning in an effort to
being able to enable -Warray-bounds globally. There is no known
behavioral bug here.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-04-30 15:56:11 +02:00
Thorsten Blum
50e638beb6 ovl: Use str_on_off() helper in ovl_show_options()
Remove hard-coded strings by using the str_on_off() helper function.

Acked-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-04-30 10:55:27 +02:00
Miklos Szeredi
b71db54ef3 ovl: don't require "metacopy=on" for "verity"
This allows the "verity" mount option to be used with "userxattr" data-only
layer(s).

Also it allows dropping the "metacopy=on" option when the "datadir+" option
is to be used.  This cleanly separates the two features that have been
lumped together under "metacopy=on":

 - data-redirect: data access is redirected to the data-only layer

 - meta-copy: copy up metadata only if possible

Previous patches made sure that with "userxattr" metacopy only works in the
lower -> data scenario.

In this scenario the lower (metadata) layer must be secured against
tampering, in which case the verity checksums contained in this layer can
ensure integrity of data even in the case of an untrusted data layer.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-04-30 10:55:27 +02:00
Miklos Szeredi
5ef7bcdeec ovl: relax redirect/metacopy requirements for lower -> data redirect
Allow the special case of a redirect from a lower layer to a data layer
without having to turn on metacopy.  This makes the feature work with
userxattr, which in turn allows data layers to be usable in user
namespaces.

Minimize the risk by only enabling redirect from a single lower layer to a
data layer iff a data layer is specified.  The only way to access a data
layer is to enable this, so there's really no reason not to enable this.

This can be used safely if the lower layer is read-only and the
user.overlay.redirect xattr cannot be modified.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-04-30 10:55:27 +02:00
Miklos Szeredi
a6fcfe9bb2 ovl: make redirect/metacopy rejection consistent
When overlayfs finds a file with metacopy and/or redirect attributes and
the metacopy and/or redirect features are not enabled, then it refuses to
act on those attributes while also issuing a warning.

There was an inconsistency in not checking metacopy found from the index.

And also only warning on an upper metacopy if it found the next file on the
lower layer, while always warning for metacopy found on a lower layer.

Fix these inconsistencies and make the logic more straightforward, paving
the way for following patches to change when data redirects are allowed.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-04-30 10:55:27 +02:00
André Almeida
924577e4f6 ovl: Fix nested backing file paths
When the lowerdir of an overlayfs is a merged directory of another
overlayfs, ovl_open_realfile() will fail to open the real file and point
to a lower dentry copy, without the proper parent path. After this,
d_path() will then display the path incorrectly as if the file is placed
in the root directory.

This bug can be triggered with the following setup:

 mkdir -p ovl-A/lower ovl-A/upper ovl-A/merge ovl-A/work
 mkdir -p ovl-B/upper ovl-B/merge ovl-B/work

 cp /bin/cat ovl-A/lower/

 mount -t overlay overlay -o \
 lowerdir=ovl-A/lower,upperdir=ovl-A/upper,workdir=ovl-A/work \
 ovl-A/merge

 mount -t overlay overlay -o \
 lowerdir=ovl-A/merge,upperdir=ovl-B/upper,workdir=ovl-B/work \
 ovl-B/merge

 ovl-A/merge/cat /proc/self/maps | grep --color cat
 ovl-B/merge/cat /proc/self/maps | grep --color cat

The first cat will correctly show `/ovl-A/merge/cat`, while the second
one shows just `/cat`.

To fix that, uses file_user_path() inside of backing_file_open() to get
the correct file path for the dentry.

Co-developed-by: John Schoenick <johns@valvesoftware.com>
Signed-off-by: John Schoenick <johns@valvesoftware.com>
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Fixes: def3ae83da ("fs: store real path instead of fake path in backing file f_path")
Cc: <stable@vger.kernel.org> # v6.7
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-04-30 10:55:27 +02:00
NeilBrown
fa6fe07d15
VFS: rename lookup_one_len family to lookup_noperm and remove permission check
The lookup_one_len family of functions is (now) only used internally by
a filesystem on itself either
- in a context where permission checking is irrelevant such as by a
  virtual filesystem populating itself, or xfs accessing its ORPHANAGE
  or dquota accessing the quota file; or
- in a context where a permission check (MAY_EXEC on the parent) has just
  been performed such as a network filesystem finding in "silly-rename"
  file in the same directory.  This is also the context after the
  _parentat() functions where currently lookup_one_qstr_excl() is used.

So the permission check is pointless.

The name "one_len" is unhelpful in understanding the purpose of these
functions and should be changed.  Most of the callers pass the len as
"strlen()" so using a qstr and QSTR() can simplify the code.

This patch renames these functions (include lookup_positive_unlocked()
which is part of the family despite the name) to have a name based on
"lookup_noperm".  They are changed to receive a 'struct qstr' instead
of separate name and len.  In a few cases the use of QSTR() results in a
new call to strlen().

try_lookup_noperm() takes a pointer to a qstr instead of the whole
qstr.  This is consistent with d_hash_and_lookup() (which is nearly
identical) and useful for lookup_noperm_unlocked().

The new lookup_noperm_common() doesn't take a qstr yet.  That will be
tidied up in a subsequent patch.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-04-08 11:24:36 +02:00
Giuseppe Scrivano
a6eb9a4a69 ovl: remove unused forward declaration
The ovl_get_verity_xattr() function was never added, only its declaration.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Fixes: 184996e92e ("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>
2025-04-07 11:22:49 +02:00