kernel.git/fs/overlayfs/file.c, branch linux-6.5.y

ovl: fix incorrect fdput() on aio completion

2023-09-23T09:14:34Z

commit 724768a39374d35b70eaeae8dd87048a2ec7ae8e upstream. ovl_{read,write}_iter() always call fdput(real) to put one or zero refcounts of the real file, but for aio, whether it was submitted or not, ovl_aio_put() also calls fdput(), which is not balanced. This is only a problem in the less common case when FDPUT_FPUT flag is set. To fix the problem use get_file() to take file refcount and use fput() instead of fdput() in ovl_aio_put(). Fixes: 2406a307ac7d ("ovl: implement async IO routines") Cc: # v5.6 Reviewed-by: Miklos Szeredi Signed-off-by: Amir Goldstein Signed-off-by: Greg Kroah-Hartman

Merge tag 'ovl-update-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs

2023-06-29T20:01:27Z

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 ...

Merge tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linux

2023-06-26T18:52:12Z

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() ...

ovl: enable fsnotify events on underlying real files

2023-06-19T16:18:04Z

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 Signed-off-by: Amir Goldstein Message-Id: <20230615112229.2143178-6-amir73il@gmail.com> Signed-off-by: Christian Brauner

fs: use backing_file container for internal files with "fake" f_path

2023-06-19T16:16:38Z

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 Message-Id: <20230615112229.2143178-5-amir73il@gmail.com> Signed-off-by: Christian Brauner

ovl: implement lazy lookup of lowerdata in data-only layers

2023-06-19T11:01:14Z

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 Reviewed-by: Alexander Larsson Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: prepare for lazy lookup of lowerdata inode

2023-06-19T11:01:14Z

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 Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

overlayfs: Implement splice-read

2023-05-24T14:42:16Z

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 Acked-by: Christian Brauner cc: Christoph Hellwig cc: Jens Axboe cc: Al Viro cc: John Hubbard cc: David Hildenbrand cc: Matthew Wilcox cc: Miklos Szeredi cc: Amir Goldstein 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

fs: port inode_owner_or_capable() to mnt_idmap

2023-01-19T08:24:29Z

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 Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Microsoft)

fs: port ->permission() to pass mnt_idmap

2023-01-19T08:24:28Z