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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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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull rename updates from Al Viro:
"Fix directory locking scheme on rename
This was broken in 6.5; we really can't lock two unrelated directories
without holding ->s_vfs_rename_mutex first and in case of same-parent
rename of a subdirectory 6.5 ends up doing just that"
* tag 'pull-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
rename(): avoid a deadlock in the case of parents having no common ancestor
kill lock_two_inodes()
rename(): fix the locking of subdirectories
f2fs: Avoid reading renamed directory if parent does not change
ext4: don't access the source subdirectory content on same-directory rename
ext2: Avoid reading renamed directory if parent does not change
udf_rename(): only access the child content on cross-directory rename
ocfs2: Avoid touching renamed directory if parent does not change
reiserfs: Avoid touching renamed directory if parent does not change
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... and fix the directory locking documentation and proof of correctness.
Holding ->s_vfs_rename_mutex *almost* prevents ->d_parent changes; the
case where we really don't want it is splicing the root of disconnected
tree to somewhere.
In other words, ->s_vfs_rename_mutex is sufficient to stabilize "X is an
ancestor of Y" only if X and Y are already in the same tree. Otherwise
it can go from false to true, and one can construct a deadlock on that.
Make lock_two_directories() report an error in such case and update the
callers of lock_rename()/lock_rename_child() to handle such errors.
And yes, such conditions are not impossible to create ;-/
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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When the index feature is disabled, ofs->indexdir is NULL.
When the index feature is enabled, ofs->indexdir has the same value as
ofs->workdir and takes an extra reference.
This makes the code harder to understand when it is not always clear
that ofs->indexdir in one function is the same dentry as ofs->workdir
in another function.
Remove this redundancy, by referencing ofs->workdir directly in index
helpers and by using the ovl_indexdir() accessor in generic code.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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Remove misleading /** prefix from a regular comment.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311121628.byHp8tkv-lkp@intel.com/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fanotify fsid updates from Christian Brauner:
"This work is part of the plan to enable fanotify to serve as a drop-in
replacement for inotify. While inotify is availabe on all filesystems,
fanotify currently isn't.
In order to support fanotify on all filesystems two things are needed:
(1) all filesystems need to support AT_HANDLE_FID
(2) all filesystems need to report a non-zero f_fsid
This contains (1) and allows filesystems to encode non-decodable file
handlers for fanotify without implementing any exportfs operations by
encoding a file id of type FILEID_INO64_GEN from i_ino and
i_generation.
Filesystems that want to opt out of encoding non-decodable file ids
for fanotify that don't support NFS export can do so by providing an
empty export_operations struct.
This also partially addresses (2) by generating f_fsid for simple
filesystems as well as freevxfs. Remaining filesystems will be dealt
with by separate patches.
Finally, this contains the patch from the current exportfs maintainers
which moves exportfs under vfs with Chuck, Jeff, and Amir as
maintainers and vfs.git as tree"
* tag 'vfs-6.7.fsid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
MAINTAINERS: create an entry for exportfs
fs: fix build error with CONFIG_EXPORTFS=m or not defined
freevxfs: derive f_fsid from bdev->bd_dev
fs: report f_fsid from s_dev for "simple" filesystems
exportfs: support encoding non-decodeable file handles by default
exportfs: define FILEID_INO64_GEN* file handle types
exportfs: make ->encode_fh() a mandatory method for NFS export
exportfs: add helpers to check if filesystem can encode/decode file handles
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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>
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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>
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overlayfs file open (ovl_maybe_lookup_lowerdata) and overlay file llseek
take the ovl_inode_lock, without holding upper sb_writers.
In case of nested lower overlay that uses same upper fs as this overlay,
lockdep will warn about (possibly false positive) circular lock
dependency when doing open/llseek of lower ovl file during copy up with
our upper sb_writers held, because the locking ordering seems reverse to
the locking order in ovl_copy_up_start():
- lower ovl_inode_lock
- upper sb_writers
Let the copy up "transaction" keeps an elevated mnt write count on upper
mnt, but leaves taking upper sb_writers to lower level helpers only when
they actually need it. This allows to avoid holding upper sb_writers
during lower file open/llseek and prevents the lockdep warning.
Minimizing the scope of upper sb_writers during copy up is also needed
for fixing another possible deadlocks by a following patch.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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Make the locking order of ovl_inode_lock() strictly between the two
vfs stacked layers, i.e.:
- ovl vfs locks: sb_writers, inode_lock, ...
- ovl_inode_lock
- upper vfs locks: sb_writers, inode_lock, ...
To that effect, move ovl_want_write() into the helpers ovl_nlink_start()
and ovl_copy_up_start which currently take the ovl_inode_lock() after
ovl_want_write().
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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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>
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ovl_copyattr() may be called concurrently from aio completion context
without any lock and that could lead to overlay inode attributes getting
permanently out of sync with real inode attributes.
Use ovl inode spinlock to protect ovl_copyattr().
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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The logic of whether filesystem can encode/decode file handles is open
coded in many places.
In preparation to changing the logic, move the open coded logic into
inline helpers.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231023180801.2953446-2-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Convert to using the new inode timestamp accessor functions.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185347.80880-58-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs
Pull overlayfs updates from Amir Goldstein:
- add verification feature needed by composefs (Alexander Larsson)
- improve integration of overlayfs and fanotify (Amir Goldstein)
- fortify some overlayfs code (Andrea Righi)
* tag 'ovl-update-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs:
ovl: validate superblock in OVL_FS()
ovl: make consistent use of OVL_FS()
ovl: Kconfig: introduce CONFIG_OVERLAY_FS_DEBUG
ovl: auto generate uuid for new overlay filesystems
ovl: store persistent uuid/fsid with uuid=on
ovl: add support for unique fsid per instance
ovl: support encoding non-decodable file handles
ovl: Handle verity during copy-up
ovl: Validate verity xattr when resolving lowerdata
ovl: Add versioned header for overlay.metacopy xattr
ovl: Add framework for verity support
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Always use OVL_FS() to retrieve the corresponding struct ovl_fs from a
struct super_block.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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Add a new mount option uuid=auto, which is the default.
If a persistent UUID xattr is found it is used.
Otherwise, an existing ovelrayfs with copied up subdirs in upper dir
that was never mounted with uuid=on retains the null UUID.
A new overlayfs with no copied up subdirs, generates the persistent UUID
on first mount.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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With uuid=on, store a persistent uuid in xattr on the upper dir to
give the overlayfs instance a persistent identifier.
This also makes f_fsid persistent and more reliable for reporting
fid info in fanotify events.
uuid=on is not supported on non-upper overlayfs or with upper fs
that does not support xattrs.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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During regular metacopy, if lowerdata file has fs-verity enabled, and
the verity option is enabled, we add the digest to the metacopy xattr.
If verity is required, and lowerdata does not have fs-verity enabled,
fall back to full copy-up (or the generated metacopy would not
validate).
Signed-off-by: Alexander Larsson <alexl@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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The new digest field in the metacopy xattr is used during lookup to
record whether the header contained a digest in the OVL_HAS_DIGEST
flags.
When accessing file data the first time, if OVL_HAS_DIGEST is set, we
reload the metadata and check that the source lowerdata inode matches
the specified digest in it (according to the enabled verity
options). If the verity check passes we store this info in the inode
flags as OVL_VERIFIED_DIGEST, so that we can avoid doing it again if
the inode remains in memory.
The verification is done in ovl_maybe_validate_verity() which needs to
be called in the same places as ovl_maybe_lookup_lowerdata(), so there
is a new ovl_verify_lowerdata() helper that calls these in the right
order, and all current callers of ovl_maybe_lookup_lowerdata() are
changed to call it instead.
Signed-off-by: Alexander Larsson <alexl@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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Historically overlay.metacopy was a zero-size xattr, and it's
existence marked a metacopy file. This change adds a versioned header
with a flag field, a length and a digest. The initial use-case of this
will be for validating a fs-verity digest, but the flags field could
also be used later for other new features.
ovl_check_metacopy_xattr() now returns the size of the xattr,
emulating a size of OVL_METACOPY_MIN_SIZE for empty xattrs to
distinguish it from the no-xattr case.
Signed-off-by: Alexander Larsson <alexl@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230705190309.579783-64-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Do all the logic to set the mode during mount options parsing and
do not keep the option string around.
Use a constant_table to translate from enum redirect mode to string
in preperation for new mount api option parsing.
The mount option "off" is translated to either "follow" or "nofollow",
depending on the "redirect_always_follow" build/module config, so
in effect, there are only three possible redirect modes.
This results in a minor change to the string that is displayed
in show_options() - when redirect_dir is enabled by default and the user
mounts with the option "redirect_dir=off", instead of displaying the mode
"redirect_dir=off" in show_options(), the displayed mode will be either
"redirect_dir=follow" or "redirect_dir=nofollow", depending on the value
of "redirect_always_follow" build/module config.
The displayed mode reflects the effective mode, so mounting overlayfs
again with the dispalyed redirect_dir option will result with the same
effective and displayed mode.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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Defer lookup of lowerdata in the data-only layers to first data access
or before copy up.
We perform lowerdata lookup before copy up even if copy up is metadata
only copy up. We can further optimize this lookup later if needed.
We do best effort lazy lookup of lowerdata for d_real_inode(), because
this interface does not expect errors. The only current in-tree caller
of d_real_inode() is trace_uprobe and this caller is likely going to be
followed reading from the file, before placing uprobes on offset within
the file, so lowerdata should be available when setting the uprobe.
Tested-by: kernel test robot <oliver.sang@intel.com>
Reviewed-by: Alexander Larsson <alexl@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Make the code handle the case of numlower > 1 and missing lowerdata
dentry gracefully.
Missing lowerdata dentry is an indication for lazy lookup of lowerdata
and in that case the lowerdata_redirect path is stored in ovl_inode.
Following commits will defer lookup and perform the lazy lookup on
access.
Reviewed-by: Alexander Larsson <alexl@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Prepare to allow ovl_lookup() to leave the last entry in a non-dir
lowerstack empty to signify lazy lowerdata lookup.
In this case, ovl_lookup() stores the redirect path from metacopy to
lowerdata in ovl_inode, which is going to be used later to perform the
lazy lowerdata lookup.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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The ovl_inode contains a copy of lowerdata in lowerstack[], so the
lowerdata inode member can be removed.
Use accessors ovl_lowerdata*() to get the lowerdata whereever the member
was accessed directly.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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The ovl_inode contains a copy of lowerpath in lowerstack[0], so the
lowerpath member can be removed.
Use accessor ovl_lowerpath() to get the lowerpath whereever the member
was accessed directly.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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The lower stacks of all the ovl inode aliases should be identical
and there is redundant information in ovl_entry and ovl_inode.
Move lowerstack into ovl_inode and keep only the OVL_E_FLAGS
per overlay dentry.
Following patches will deduplicate redundant ovl_inode fields.
Note that for pure upper and negative dentries, OVL_E(dentry) may be
NULL now, so it is imporatnt to use the ovl_numlower() accessor.
Reviewed-by: Alexander Larsson <alexl@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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In preparation for moving lowerstack into ovl_inode.
Note that in ovl_lookup() the temp stack dentry refs are now cloned
into the final ovl_lowerstack instead of being transferred, so cleanup
always needs to call ovl_stack_free(stack).
Reviewed-by: Alexander Larsson <alexl@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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This helps fortify against dereferencing a NULL ovl_entry,
before we move the ovl_entry reference into ovl_inode.
Reviewed-by: Alexander Larsson <alexl@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Instead of open coded instances, because we are about to split
the two apart.
Reviewed-by: Alexander Larsson <alexl@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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After copy up, we may need to update d_flags if upper dentry is on a
remote fs and lower dentries are not.
Add helpers to allow incremental update of the revalidate flags.
Fixes: bccece1ead36 ("ovl: allow remote upper")
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Let helper ovl_i_path_real() return the realinode to prepare for
checking non-null realinode in RCU walking path.
[msz] Use d_inode_rcu() since we are depending on the consitency
between dentry and inode being non-NULL in an RCU setting.
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Fixes: ffa5723c6d25 ("ovl: store lower path in ovl_inode")
Cc: <stable@vger.kernel.org> # v5.19
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Convert to struct mnt_idmap.
Remove legacy file_mnt_user_ns() and mnt_user_ns().
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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Passing dentry to some helpers is unnecessary. Simplify these cases.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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A while ago we introduced a dedicated vfs{g,u}id_t type in commit
1e5267cd0895 ("mnt_idmapping: add vfs{g,u}id_t"). We already switched
over a good part of the VFS. Ultimately we will remove all legacy
idmapped mount helpers that operate only on k{g,u}id_t in favor of the
new type safe helpers that operate on vfs{g,u}id_t.
Cc: Seth Forshee (Digital Ocean) <sforshee@kernel.org>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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In earlier patches we already passed down the relevant upper or lower
path to ovl_open_realfile(). Now let the open helpers actually take the
idmapping of the relevant mount into account when checking permissions.
This is needed to support idmapped base layers with overlay.
Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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When copying inode attributes from the upper or lower layer to ovl inodes
we need to take the upper or lower layer's mount's idmapping into
account. In a lot of places we call ovl_copyattr() only on upper inodes and
in some we call it on either upper or lower inodes. Split this into two
separate helpers.
The first one should only be called on upper
inodes and is thus called ovl_copy_upperattr(). The second one can be
called on upper or lower inodes. We add ovl_copy_realattr() for this
task. The new helper makes use of the previously added ovl_i_path_real()
helper. This is needed to support idmapped base layers with overlay.
When overlay copies the inode information from an upper or lower layer
to the relevant overlay inode it will apply the idmapping of the upper
or lower layer when doing so. The ovl inode ownership will thus always
correctly reflect the ownership of the idmapped upper or lower layer.
All idmapping helpers are nops when no idmapped base layers are used.
Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Create some ovl_i_* helpers to get real path from ovl inode. Instead of
just stashing struct inode for the lower layer we stash struct path for
the lower layer. The helpers allow to retrieve a struct path for the
relevant upper or lower layer. This will be used when retrieving
information based on struct inode when copying up inode attributes from
upper or lower inodes to ovl inodes and when checking permissions in
ovl_permission() in following patches. This is needed to support
idmapped base layers with overlay.
Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Add a helper that allows to retrieve ovl xattrs from either lower or
upper layers. To stop passing mnt and dentry separately everywhere use
struct path which more accurately reflects the tight coupling between
mount and dentry in this helper. Swich over all places to pass a path
argument that can operate on either upper or lower layers. This is
needed to support idmapped base layers with overlayfs.
Some helpers are always called with an upper dentry, which is now utilized
by these helpers to create the path. Make this usage explicit by renaming
the argument to "upperdentry" and by renaming the function as well in some
cases. Also add a check in ovl_do_getxattr() to catch misuse of these
functions.
Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Introduce ovl_lookup_upper() as a simple wrapper around lookup_one().
Make it clear in the helper's name that this only operates on the upper
layer. The wrapper will take upper layer's idmapping into account when
checking permission in lookup_one().
Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Ensure that ovl_open_realfile() takes the mount's idmapping into
account. We add a new helper ovl_path_realdata() that can be used to
easily retrieve the relevant path which we can pass down. This is needed
to support idmapped base layers with overlay.
Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Pass down struct ovl_fs to all creation helpers so we can ultimately
retrieve the relevant upper mount and take the mount's idmapping into
account when creating new filesystem objects. This is needed to support
idmapped base layers with overlay.
Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Use helpers ovl_*xattr() to access user/trusted.overlay.* xattrs
and use helpers ovl_do_*xattr() to access generic xattrs. This is a
preparatory patch for using idmapped base layers with overlay.
Note that a few of those places called vfs_*xattr() calls directly to
reduce the amount of debug output. But as Miklos pointed out since
overlayfs has been stable for quite some time the debug output isn't all
that relevant anymore and the additional debug in all locations was
actually quite helpful when developing this patch series.
Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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When a lower file has immutable/append-only fileattr flags, the behavior of
overlayfs post copy up is inconsistent.
Immediattely after copy up, ovl inode still has the S_IMMUTABLE/S_APPEND
inode flags copied from lower inode, so vfs code still treats the ovl inode
as immutable/append-only. After ovl inode evict or mount cycle, the ovl
inode does not have these inode flags anymore.
We cannot copy up the immutable and append-only fileattr flags, because
immutable/append-only inodes cannot be linked and because overlayfs will
not be able to set overlay.* xattr on the upper inodes.
Instead, if any of the fileattr flags of interest exist on the lower inode,
we store them in overlay.protattr xattr on the upper inode and we read the
flags from xattr on lookup and on fileattr_get().
This gives consistent behavior post copy up regardless of inode eviction
from cache.
When user sets new fileattr flags, we update or remove the overlay.protattr
xattr.
Storing immutable/append-only fileattr flags in an xattr instead of upper
fileattr also solves other non-standard behavior issues - overlayfs can now
copy up children of "ovl-immutable" directories and lower aliases of
"ovl-immutable" hardlinks.
Reported-by: Chengguang Xu <cgxu519@mykernel.net>
Link: https://lore.kernel.org/linux-unionfs/20201226104618.239739-1-cgxu519@mykernel.net/
Link: https://lore.kernel.org/linux-unionfs/20210210190334.1212210-5-amir73il@gmail.com/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Instead of passing the overlay dentry.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Amir Goldstein
Linus Torvalds
Al Viro
Alexander Larsson
Jeff Layton
Andrea Righi
Zhihao Cheng
Christian Brauner
Miklos Szeredi
