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2023-07-03ovl: move all parameter handling into params.{c,h}Christian Brauner4-564/+581
While initially I thought that we couldn't move all new mount api handling into params.{c,h} it turns out it is possible. So this just moves a good chunk of code out of super.c and into params.{c,h}. Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-06-29Merge tag 'ovl-update-6.5' of ↵Linus Torvalds13-699/+1350
git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs Pull overlayfs update from Amir Goldstein: - fix two NULL pointer deref bugs (Zhihao Cheng) - add support for "data-only" lower layers destined to be used by composefs - port overlayfs to the new mount api (Christian Brauner) * tag 'ovl-update-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs: (26 commits) ovl: add Amir as co-maintainer ovl: reserve ability to reconfigure mount options with new mount api ovl: modify layer parameter parsing ovl: port to new mount api ovl: factor out ovl_parse_options() helper ovl: store enum redirect_mode in config instead of a string ovl: pass ovl_fs to xino helpers ovl: clarify ovl_get_root() semantics ovl: negate the ofs->share_whiteout boolean ovl: check type and offset of struct vfsmount in ovl_entry ovl: implement lazy lookup of lowerdata in data-only layers ovl: prepare for lazy lookup of lowerdata inode ovl: prepare to store lowerdata redirect for lazy lowerdata lookup ovl: implement lookup in data-only layers ovl: introduce data-only lower layers ovl: remove unneeded goto instructions ovl: deduplicate lowerdata and lowerstack[] ovl: deduplicate lowerpath and lowerstack[] ovl: move ovl_entry into ovl_inode ovl: factor out ovl_free_entry() and ovl_stack_*() helpers ...
2023-06-26Merge tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linuxLinus Torvalds1-1/+22
Pull splice updates from Jens Axboe: "This kills off ITER_PIPE to avoid a race between truncate, iov_iter_revert() on the pipe and an as-yet incomplete DMA to a bio with unpinned/unref'ed pages from an O_DIRECT splice read. This causes memory corruption. Instead, we either use (a) filemap_splice_read(), which invokes the buffered file reading code and splices from the pagecache into the pipe; (b) copy_splice_read(), which bulk-allocates a buffer, reads into it and then pushes the filled pages into the pipe; or (c) handle it in filesystem-specific code. Summary: - Rename direct_splice_read() to copy_splice_read() - Simplify the calculations for the number of pages to be reclaimed in copy_splice_read() - Turn do_splice_to() into a helper, vfs_splice_read(), so that it can be used by overlayfs and coda to perform the checks on the lower fs - Make vfs_splice_read() jump to copy_splice_read() to handle direct-I/O and DAX - Provide shmem with its own splice_read to handle non-existent pages in the pagecache. We don't want a ->read_folio() as we don't want to populate holes, but filemap_get_pages() requires it - Provide overlayfs with its own splice_read to call down to a lower layer as overlayfs doesn't provide ->read_folio() - Provide coda with its own splice_read to call down to a lower layer as coda doesn't provide ->read_folio() - Direct ->splice_read to copy_splice_read() in tty, procfs, kernfs and random files as they just copy to the output buffer and don't splice pages - Provide wrappers for afs, ceph, ecryptfs, ext4, f2fs, nfs, ntfs3, ocfs2, orangefs, xfs and zonefs to do locking and/or revalidation - Make cifs use filemap_splice_read() - Replace pointers to generic_file_splice_read() with pointers to filemap_splice_read() as DIO and DAX are handled in the caller; filesystems can still provide their own alternate ->splice_read() op - Remove generic_file_splice_read() - Remove ITER_PIPE and its paraphernalia as generic_file_splice_read was the only user" * tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linux: (31 commits) splice: kdoc for filemap_splice_read() and copy_splice_read() iov_iter: Kill ITER_PIPE splice: Remove generic_file_splice_read() splice: Use filemap_splice_read() instead of generic_file_splice_read() cifs: Use filemap_splice_read() trace: Convert trace/seq to use copy_splice_read() zonefs: Provide a splice-read wrapper xfs: Provide a splice-read wrapper orangefs: Provide a splice-read wrapper ocfs2: Provide a splice-read wrapper ntfs3: Provide a splice-read wrapper nfs: Provide a splice-read wrapper f2fs: Provide a splice-read wrapper ext4: Provide a splice-read wrapper ecryptfs: Provide a splice-read wrapper ceph: Provide a splice-read wrapper afs: Provide a splice-read wrapper 9p: Add splice_read wrapper net: Make sock_splice_read() use copy_splice_read() by default tty, proc, kernfs, random: Use copy_splice_read() ...
2023-06-20ovl: reserve ability to reconfigure mount options with new mount apiChristian Brauner1-7/+18
Using the old mount api to remount an overlayfs superblock via mount(MS_REMOUNT) all mount options will be silently ignored. For example, if you create an overlayfs mount: mount -t overlay overlay -o lowerdir=/mnt/a:/mnt/b,upperdir=/mnt/upper,workdir=/mnt/work /mnt/merged and then issue a remount via: # force mount(8) to use mount(2) export LIBMOUNT_FORCE_MOUNT2=always mount -t overlay overlay -o remount,WOOTWOOT,lowerdir=/DOESNT-EXIST /mnt/merged with completely nonsensical mount options whatsoever it will succeed nonetheless. This prevents us from every changing any mount options we might introduce in the future that could reasonably be changed during a remount. We don't need to carry this issue into the new mount api port. Similar to FUSE we can use the fs_context::oldapi member to figure out that this is a request coming through the legacy mount api. If we detect it we continue silently ignoring all mount options. But for the new mount api we simply report that mount options cannot currently be changed. This will allow us to potentially alter mount properties for new or even old properties. It any case, silently ignoring everything is not something new apis should do. Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-06-20ovl: modify layer parameter parsingChristian Brauner5-258/+520
We ran into issues where mount(8) passed multiple lower layers as one big string through fsconfig(). But the fsconfig() FSCONFIG_SET_STRING option is limited to 256 bytes in strndup_user(). While this would be fixable by extending the fsconfig() buffer I'd rather encourage users to append layers via multiple fsconfig() calls as the interface allows nicely for this. This has also been requested as a feature before. With this port to the new mount api the following will be possible: fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir", "/lower1", 0); /* set upper layer */ fsconfig(fs_fd, FSCONFIG_SET_STRING, "upperdir", "/upper", 0); /* append "/lower2", "/lower3", and "/lower4" */ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir", ":/lower2:/lower3:/lower4", 0); /* turn index feature on */ fsconfig(fs_fd, FSCONFIG_SET_STRING, "index", "on", 0); /* append "/lower5" */ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir", ":/lower5", 0); Specifying ':' would have been rejected so this isn't a regression. And we can't simply use "lowerdir=/lower" to append on top of existing layers as "lowerdir=/lower,lowerdir=/other-lower" would make "/other-lower" the only lower layer so we'd break uapi if we changed this. So the ':' prefix seems a good compromise. Users can choose to specify multiple layers at once or individual layers. A layer is appended if it starts with ":". This requires that the user has already added at least one layer before. If lowerdir is specified again without a leading ":" then all previous layers are dropped and replaced with the new layers. If lowerdir is specified and empty than all layers are simply dropped. An additional change is that overlayfs will now parse and resolve layers right when they are specified in fsconfig() instead of deferring until super block creation. This allows users to receive early errors. It also allows users to actually use up to 500 layers something which was theoretically possible but ended up not working due to the mount option string passed via mount(2) being too large. This also allows a more privileged process to set config options for a lesser privileged process as the creds for fsconfig() and the creds for fsopen() can differ. We could restrict that they match by enforcing that the creds of fsopen() and fsconfig() match but I don't see why that needs to be the case and allows for a good delegation mechanism. Plus, in the future it means we're able to extend overlayfs mount options and allow users to specify layers via file descriptors instead of paths: fsconfig(FSCONFIG_SET_PATH{_EMPTY}, "lowerdir", "lower1", dirfd); /* append */ fsconfig(FSCONFIG_SET_PATH{_EMPTY}, "lowerdir", "lower2", dirfd); /* append */ fsconfig(FSCONFIG_SET_PATH{_EMPTY}, "lowerdir", "lower3", dirfd); /* clear all layers specified until now */ fsconfig(FSCONFIG_SET_STRING, "lowerdir", NULL, 0); This would be especially nice if users create an overlayfs mount on top of idmapped layers or just in general private mounts created via open_tree(OPEN_TREE_CLONE). Those mounts would then never have to appear anywhere in the filesystem. But for now just do the minimal thing. We should probably aim to move more validation into ovl_fs_parse_param() so users get errors before fsconfig(FSCONFIG_CMD_CREATE). But that can be done in additional patches later. This is now also rebased on top of the lazy lowerdata lookup which allows the specificatin of data only layers using the new "::" syntax. The rules are simple. A data only layers cannot be followed by any regular layers and data layers must be preceeded by at least one regular layer. Parsing the lowerdir mount option must change because of this. The original patchset used the old lowerdir parsing function to split a lowerdir mount option string such as: lowerdir=/lower1:/lower2::/lower3::/lower4 simply replacing each non-escaped ":" by "\0". So sequences of non-escaped ":" were counted as layers. For example, the previous lowerdir mount option above would've counted 6 layers instead of 4 and a lowerdir mount option such as: lowerdir="/lower1:/lower2::/lower3::/lower4:::::::::::::::::::::::::::" would be counted as 33 layers. Other than being ugly this didn't matter much because kern_path() would reject the first "\0" layer. However, this overcounting of layers becomes problematic when we base allocations on it where we very much only want to allocate space for 4 layers instead of 33. So the new parsing function rejects non-escaped sequences of colons other than ":" and "::" immediately instead of relying on kern_path(). Link: https://github.com/util-linux/util-linux/issues/2287 Link: https://github.com/util-linux/util-linux/issues/1992 Link: https://bugs.archlinux.org/task/78702 Link: https://lore.kernel.org/linux-unionfs/20230530-klagen-zudem-32c0908c2108@brauner Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-06-19ovl: enable fsnotify events on underlying real filesAmir Goldstein1-2/+2
Overlayfs creates the real underlying files with fake f_path, whose f_inode is on the underlying fs and f_path on overlayfs. Those real files were open with FMODE_NONOTIFY, because fsnotify code was not prapared to handle fsnotify hooks on files with fake path correctly and fanotify would report unexpected event->fd with fake overlayfs path, when the underlying fs was being watched. Teach fsnotify to handle events on the real files, and do not set real files to FMODE_NONOTIFY to allow operations on real file (e.g. open, access, modify, close) to generate async and permission events. Because fsnotify does not have notifications on address space operations, we do not need to worry about ->vm_file not reporting events to a watched overlayfs when users are accessing a mapped overlayfs file. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Message-Id: <20230615112229.2143178-6-amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-06-19fs: use backing_file container for internal files with "fake" f_pathAmir Goldstein1-2/+2
Overlayfs uses open_with_fake_path() to allocate internal kernel files, with a "fake" path - whose f_path is not on the same fs as f_inode. Allocate a container struct backing_file for those internal files, that is used to hold the "fake" ovl path along with the real path. backing_file_real_path() can be used to access the stored real path. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Message-Id: <20230615112229.2143178-5-amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-06-19fs: rename {vfs,kernel}_tmpfile_open()Amir Goldstein1-2/+3
Overlayfs and cachefiles use vfs_open_tmpfile() to open a tmpfile without accounting for nr_files. Rename this helper to kernel_tmpfile_open() to better reflect this helper is used for kernel internal users. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Message-Id: <20230615112229.2143178-2-amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-06-19ovl: port to new mount apiChristian Brauner1-205/+193
We recently ported util-linux to the new mount api. Now the mount(8) tool will by default use the new mount api. While trying hard to fall back to the old mount api gracefully there are still cases where we run into issues that are difficult to handle nicely. Now with mount(8) and libmount supporting the new mount api I expect an increase in the number of bug reports and issues we're going to see with filesystems that don't yet support the new mount api. So it's time we rectify this. When ovl_fill_super() fails before setting sb->s_root, we need to cleanup sb->s_fs_info. The logic is a bit convoluted but tl;dr: If sget_fc() has succeeded fc->s_fs_info will have been transferred to sb->s_fs_info. So by the time ->fill_super()/ovl_fill_super() is called fc->s_fs_info is NULL consequently fs_context->free() won't call ovl_free_fs(). If we fail before sb->s_root() is set then ->put_super() won't be called which would call ovl_free_fs(). IOW, if we fail in ->fill_super() before sb->s_root we have to clean it up. Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-06-19ovl: factor out ovl_parse_options() helperAmir Goldstein2-116/+135
For parsing a single mount option. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-06-19ovl: store enum redirect_mode in config instead of a stringAmir Goldstein6-84/+103
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>
2023-06-19ovl: pass ovl_fs to xino helpersAmir Goldstein4-31/+43
Internal ovl methods should use ovl_fs and not sb as much as possible. Use a constant_table to translate from enum xino mode to string in preperation for new mount api option parsing. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-06-19ovl: clarify ovl_get_root() semanticsAmir Goldstein1-1/+3
Change the semantics to take a reference on upperdentry instead of transferrig the reference. This is needed for upcoming port to new mount api. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-06-19ovl: negate the ofs->share_whiteout booleanAmir Goldstein3-7/+4
The default common case is that whiteout sharing is enabled. Change to storing the negated no_shared_whiteout state, so we will not need to initialize it. This is the first step towards removing all config and feature initializations out of ovl_fill_super(). Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-06-19ovl: check type and offset of struct vfsmount in ovl_entryChristian Brauner1-0/+9
Porting overlayfs to the new amount api I started experiencing random crashes that couldn't be explained easily. So after much debugging and reasoning it became clear that struct ovl_entry requires the point to struct vfsmount to be the first member and of type struct vfsmount. During the port I added a new member at the beginning of struct ovl_entry which broke all over the place in the form of random crashes and cache corruptions. While there's a comment in ovl_free_fs() to the effect of "Hack! Reuse ofs->layers as a vfsmount array before freeing it" there's no such comment on struct ovl_entry which makes this easy to trip over. Add a comment and two static asserts for both the offset and the type of pointer in struct ovl_entry. Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-06-19ovl: implement lazy lookup of lowerdata in data-only layersAmir Goldstein7-14/+107
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>
2023-06-19ovl: prepare for lazy lookup of lowerdata inodeAmir Goldstein4-5/+33
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>
2023-06-19ovl: prepare to store lowerdata redirect for lazy lowerdata lookupAmir Goldstein6-4/+24
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>
2023-06-19ovl: implement lookup in data-only layersAmir Goldstein1-1/+72
Lookup in data-only layers only for a lower metacopy with an absolute redirect xattr. The metacopy xattr is not checked on files found in the data-only layers and redirect xattr are not followed in the data-only layers. Reviewed-by: Alexander Larsson <alexl@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2023-06-19ovl: introduce data-only lower layersAmir Goldstein3-8/+72
Introduce the format lowerdir=lower1:lower2::lowerdata1::lowerdata2 where the lower layers on the right of the :: separators are not merged into the overlayfs merge dirs. Data-only lower layers are only allowed at the bottom of the stack. The files in those layers are only meant to be accessible via absolute redirect from metacopy files in lower layers. Following changes will implement lookup in the data layers. This feature was requested for composefs ostree use case, where the lower data layer should only be accessiable via absolute redirects from metacopy inodes. The lower data layers are not required to a have a unique uuid or any uuid at all, because they are never used to compose the overlayfs inode st_ino/st_dev. Reviewed-by: Alexander Larsson <alexl@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2023-06-19ovl: remove unneeded goto instructionsAmir Goldstein1-12/+9
There is nothing in the out goto target of ovl_get_layers(). Reviewed-by: Alexander Larsson <alexl@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2023-06-19ovl: deduplicate lowerdata and lowerstack[]Amir Goldstein6-17/+22
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>
2023-06-19ovl: deduplicate lowerpath and lowerstack[]Amir Goldstein7-21/+13
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>
2023-06-19ovl: move ovl_entry into ovl_inodeAmir Goldstein8-62/+57
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>
2023-06-19ovl: factor out ovl_free_entry() and ovl_stack_*() helpersAmir Goldstein5-22/+46
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>
2023-06-19ovl: use ovl_numlower() and ovl_lowerstack() accessorsAmir Goldstein5-52/+73
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>
2023-06-19ovl: use OVL_E() and OVL_E_FLAGS() accessorsAmir Goldstein5-16/+21
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>
2023-06-19ovl: update of dentry revalidate flags after copy upAmir Goldstein7-13/+30
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>
2023-06-19ovl: fix null pointer dereference in ovl_get_acl_rcu()Zhihao Cheng1-6/+6
Following process: P1 P2 path_openat link_path_walk may_lookup inode_permission(rcu) ovl_permission acl_permission_check check_acl get_cached_acl_rcu ovl_get_inode_acl realinode = ovl_inode_real(ovl_inode) drop_cache __dentry_kill(ovl_dentry) iput(ovl_inode) ovl_destroy_inode(ovl_inode) dput(oi->__upperdentry) dentry_kill(upperdentry) dentry_unlink_inode upperdentry->d_inode = NULL ovl_inode_upper upperdentry = ovl_i_dentry_upper(ovl_inode) d_inode(upperdentry) // returns NULL IS_POSIXACL(realinode) // NULL pointer dereference , will trigger an null pointer dereference at realinode: [ 205.472797] BUG: kernel NULL pointer dereference, address: 0000000000000028 [ 205.476701] CPU: 2 PID: 2713 Comm: ls Not tainted 6.3.0-12064-g2edfa098e750-dirty #1216 [ 205.478754] RIP: 0010:do_ovl_get_acl+0x5d/0x300 [ 205.489584] Call Trace: [ 205.489812] <TASK> [ 205.490014] ovl_get_inode_acl+0x26/0x30 [ 205.490466] get_cached_acl_rcu+0x61/0xa0 [ 205.490908] generic_permission+0x1bf/0x4e0 [ 205.491447] ovl_permission+0x79/0x1b0 [ 205.491917] inode_permission+0x15e/0x2c0 [ 205.492425] link_path_walk+0x115/0x550 [ 205.493311] path_lookupat.isra.0+0xb2/0x200 [ 205.493803] filename_lookup+0xda/0x240 [ 205.495747] vfs_fstatat+0x7b/0xb0 Fetch a reproducer in [Link]. Use the helper ovl_i_path_realinode() to get realinode and then do non-nullptr checking. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217404 Fixes: 332f606b32b6 ("ovl: enable RCU'd ->get_acl()") Cc: <stable@vger.kernel.org> # v5.15 Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Suggested-by: Christian Brauner <brauner@kernel.org> Suggested-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2023-06-19ovl: fix null pointer dereference in ovl_permission()Zhihao Cheng1-3/+2
Following process: P1 P2 path_lookupat link_path_walk inode_permission ovl_permission ovl_i_path_real(inode, &realpath) path->dentry = ovl_i_dentry_upper(inode) drop_cache __dentry_kill(ovl_dentry) iput(ovl_inode) ovl_destroy_inode(ovl_inode) dput(oi->__upperdentry) dentry_kill(upperdentry) dentry_unlink_inode upperdentry->d_inode = NULL realinode = d_inode(realpath.dentry) // return NULL inode_permission(realinode) inode->i_sb // NULL pointer dereference , will trigger an null pointer dereference at realinode: [ 335.664979] BUG: kernel NULL pointer dereference, address: 0000000000000002 [ 335.668032] CPU: 0 PID: 2592 Comm: ls Not tainted 6.3.0 [ 335.669956] RIP: 0010:inode_permission+0x33/0x2c0 [ 335.678939] Call Trace: [ 335.679165] <TASK> [ 335.679371] ovl_permission+0xde/0x320 [ 335.679723] inode_permission+0x15e/0x2c0 [ 335.680090] link_path_walk+0x115/0x550 [ 335.680771] path_lookupat.isra.0+0xb2/0x200 [ 335.681170] filename_lookup+0xda/0x240 [ 335.681922] vfs_statx+0xa6/0x1f0 [ 335.682233] vfs_fstatat+0x7b/0xb0 Fetch a reproducer in [Link]. Use the helper ovl_i_path_realinode() to get realinode and then do non-nullptr checking. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217405 Fixes: 4b7791b2e958 ("ovl: handle idmappings in ovl_permission()") Cc: <stable@vger.kernel.org> # v5.19 Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Suggested-by: Christian Brauner <brauner@kernel.org> Suggested-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2023-06-19ovl: let helper ovl_i_path_real() return the realinodeZhihao Cheng2-4/+5
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>
2023-05-24overlayfs: Implement splice-readDavid Howells1-1/+22
Implement splice-read for overlayfs by passing the request down a layer rather than going through generic_file_splice_read() which is going to be changed to assume that ->read_folio() is present on buffered files. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Christian Brauner <brauner@kernel.org> cc: Christoph Hellwig <hch@lst.de> cc: Jens Axboe <axboe@kernel.dk> cc: Al Viro <viro@zeniv.linux.org.uk> cc: John Hubbard <jhubbard@nvidia.com> cc: David Hildenbrand <david@redhat.com> cc: Matthew Wilcox <willy@infradead.org> cc: Miklos Szeredi <miklos@szeredi.hu> cc: Amir Goldstein <amir73il@gmail.com> cc: linux-unionfs@vger.kernel.org cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org Link: https://lore.kernel.org/r/20230522135018.2742245-11-dhowells@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-03-06ovl: check for ->listxattr() supportChristian Brauner1-2/+1
We have decoupled vfs_listxattr() from IOP_XATTR. Instead we just need to check whether inode->i_op->listxattr is implemented. Cc: linux-unionfs@vger.kernel.org Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-03-06fs: drop unused posix acl handlersChristian Brauner1-8/+0
Remove struct posix_acl_{access,default}_handler for all filesystems that don't depend on the xattr handler in their inode->i_op->listxattr() method in any way. There's nothing more to do than to simply remove the handler. It's been effectively unused ever since we introduced the new posix acl api. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-02-20Merge tag 'fs.idmapped.v6.3' of ↵Linus Torvalds10-78/+79
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping Pull vfs idmapping updates from Christian Brauner: - Last cycle we introduced the dedicated struct mnt_idmap type for mount idmapping and the required infrastucture in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). As promised in last cycle's pull request message this converts everything to rely on 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 relevant on the mount level. Especially for non-vfs developers without detailed knowledge in this area this was a potential source for bugs. This finishes the conversion. Instead of passing the plain namespace around this updates all places that currently take a pointer to a mnt_userns with a pointer to struct mnt_idmap. Now that the conversion is done all helpers down to the really low-level helpers only accept a struct mnt_idmap argument instead of two namespace arguments. Conflating mount and other idmappings will now cause the compiler to complain loudly thus eliminating the possibility of any bugs. This makes it impossible for filesystem developers to mix up mount and filesystem idmappings as they are two distinct types and require distinct helpers that cannot be used interchangeably. Everything associated with struct mnt_idmap is moved into a single separate file. With that change no code can poke around in struct mnt_idmap. It can only be interacted with through dedicated helpers. That means all filesystems are and all of the vfs is completely oblivious to the actual implementation of idmappings. We are now also able to extend struct mnt_idmap as we see fit. For example, we can decouple it completely from namespaces for users that don't require or don't want to use them at all. We can also extend the concept of idmappings so we can cover filesystem specific requirements. In combination with the vfs{g,u}id_t work we finished in v6.2 this makes this feature substantially more robust and thus difficult to implement wrong by a given filesystem and also protects the vfs. - Enable idmapped mounts for tmpfs and fulfill a longstanding request. A long-standing request from users had been to make it possible to create idmapped mounts for tmpfs. For example, to share the host's tmpfs mount between multiple sandboxes. This is a prerequisite for some advanced Kubernetes cases. Systemd also has a range of use-cases to increase service isolation. And there are more users of this. However, with all of the other work going on this was way down on the priority list but luckily someone other than ourselves picked this up. As usual the patch is tiny as all the infrastructure work had been done multiple kernel releases ago. In addition to all the tests that we already have I requested that Rodrigo add a dedicated tmpfs testsuite for idmapped mounts to xfstests. It is to be included into xfstests during the v6.3 development cycle. This should add a slew of additional tests. * tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits) shmem: support idmapped mounts for tmpfs fs: move mnt_idmap fs: port vfs{g,u}id helpers to mnt_idmap fs: port fs{g,u}id helpers to mnt_idmap fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap fs: port i_{g,u}id_{needs_}update() to mnt_idmap quota: port to mnt_idmap fs: port privilege checking helpers to mnt_idmap fs: port inode_owner_or_capable() to mnt_idmap fs: port inode_init_owner() to mnt_idmap fs: port acl to mnt_idmap fs: port xattr to mnt_idmap fs: port ->permission() to pass mnt_idmap fs: port ->fileattr_set() to pass mnt_idmap fs: port ->set_acl() to pass mnt_idmap fs: port ->get_acl() to pass mnt_idmap fs: port ->tmpfile() to pass mnt_idmap fs: port ->rename() to pass mnt_idmap fs: port ->mknod() to pass mnt_idmap fs: port ->mkdir() to pass mnt_idmap ...
2023-01-27ovl: fail on invalid uid/gid mapping at copy upMiklos Szeredi1-0/+4
If st_uid/st_gid doesn't have a mapping in the mounter's user_ns, then copy-up should fail, just like it would fail if the mounter task was doing the copy using "cp -a". There's a corner case where the "cp -a" would succeed but copy up fail: if there's a mapping of the invalid uid/gid (65534 by default) in the user namespace. This is because stat(2) will return this value if the mapping doesn't exist in the current user_ns and "cp -a" will in turn be able to create a file with this uid/gid. This behavior would be inconsistent with POSIX ACL's, which return -1 for invalid uid/gid which result in a failed copy. For consistency and simplicity fail the copy of the st_uid/st_gid are invalid. Fixes: 459c7c565ac3 ("ovl: unprivieged mounts") Cc: <stable@vger.kernel.org> # v5.11 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Seth Forshee <sforshee@kernel.org>
2023-01-27ovl: fix tmpfile leakMiklos Szeredi1-1/+1
Missed an error cleanup. Reported-by: syzbot+fd749a7ea127a84e0ffd@syzkaller.appspotmail.com Fixes: 2b1a77461f16 ("ovl: use vfs_tmpfile_open() helper") Cc: <stable@vger.kernel.org> # v6.1 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2023-01-19fs: port vfs{g,u}id helpers to mnt_idmapChristian Brauner1-6/+4
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>
2023-01-19fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmapChristian Brauner1-4/+4
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>
2023-01-19fs: port privilege checking helpers to mnt_idmapChristian Brauner1-1/+1
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>
2023-01-19fs: port inode_owner_or_capable() to mnt_idmapChristian Brauner3-6/+3
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>
2023-01-19fs: port inode_init_owner() to mnt_idmapChristian Brauner1-1/+1
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>
2023-01-19fs: port xattr to mnt_idmapChristian Brauner1-2/+2
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>
2023-01-19fs: port ->permission() to pass mnt_idmapChristian Brauner8-26/+24
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>
2023-01-19fs: port ->fileattr_set() to pass mnt_idmapChristian Brauner2-3/+3
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>
2023-01-19fs: port ->set_acl() to pass mnt_idmapChristian Brauner2-4/+4
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>
2023-01-19fs: port ->get_acl() to pass mnt_idmapChristian Brauner2-8/+10
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>
2023-01-19fs: port ->rename() to pass mnt_idmapChristian Brauner1-1/+1
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>
2023-01-19fs: port ->mknod() to pass mnt_idmapChristian Brauner1-1/+1
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>
2023-01-19fs: port ->mkdir() to pass mnt_idmapChristian Brauner1-1/+1
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>