kernel/git/stable/linux.git/Documentation/filesystems, branch linux-6.7.y

ovl: mark xwhiteouts directory with overlay.opaque='x'

2024-02-01T00:21:11+00:00

commit 420332b94119cdc7db4477cc88484691cb92ae71 upstream. 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: # v6.7 Reviewed-by: Alexander Larsson Tested-by: Alexander Larsson Signed-off-by: Amir Goldstein Signed-off-by: Greg Kroah-Hartman

rename(): fix the locking of subdirectories

2024-02-01T00:21:03+00:00

commit 22e111ed6c83dcde3037fc81176012721bc34c0b upstream. We should never lock two subdirectories without having taken ->s_vfs_rename_mutex; inode pointer order or not, the "order" proposed in 28eceeda130f "fs: Lock moved directories" is not transitive, with the usual consequences. The rationale for locking renamed subdirectory in all cases was the possibility of race between rename modifying .. in a subdirectory to reflect the new parent and another thread modifying the same subdirectory. For a lot of filesystems that's not a problem, but for some it can lead to trouble (e.g. the case when short directory contents is kept in the inode, but creating a file in it might push it across the size limit and copy its contents into separate data block(s)). However, we need that only in case when the parent does change - otherwise ->rename() doesn't need to do anything with .. entry in the first place. Some instances are lazy and do a tautological update anyway, but it's really not hard to avoid. Amended locking rules for rename(): find the parent(s) of source and target if source and target have the same parent lock the common parent else lock ->s_vfs_rename_mutex lock both parents, in ancestor-first order; if neither is an ancestor of another, lock the parent of source first. find the source and target. if source and target have the same parent if operation is an overwriting rename of a subdirectory lock the target subdirectory else if source is a subdirectory lock the source if target is a subdirectory lock the target lock non-directories involved, in inode pointer order if both source and target are such. That way we are guaranteed that parents are locked (for obvious reasons), that any renamed non-directory is locked (nfsd relies upon that), that any victim is locked (emptiness check needs that, among other things) and subdirectory that changes parent is locked (needed to protect the update of .. entries). We are also guaranteed that any operation locking more than one directory either takes ->s_vfs_rename_mutex or locks a parent followed by its child. Cc: stable@vger.kernel.org Fixes: 28eceeda130f "fs: Lock moved directories" Reviewed-by: Jan Kara Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

docs/fuse-io: Document the usage of DIRECT_IO_ALLOW_MMAP

2023-12-04T09:16:53+00:00

By default, shared mmap is disabled in FUSE DIRECT_IO mode. However, when the DIRECT_IO_ALLOW_MMAP flag is enabled in the FUSE_INIT reply, shared mmap is allowed. Signed-off-by: Tyler Fanelli Signed-off-by: Miklos Szeredi

MAINTAINERS: erofs: add EROFS webpage

2023-11-17T11:55:46+00:00

Add a new `W:` field of the EROFS entry points to the documentation site at . In addition, update the in-tree documentation and Kconfig too. Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20231117085329.1624223-1-hsiangkao@linux.alibaba.com

Merge tag 'vfs-6.7.fsid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2023-11-07T20:11:26+00:00

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

Merge tag 'ovl-update-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs

2023-11-07T19:46:31+00:00

Pull overlayfs updates from Amir Goldstein: - Overlayfs aio cleanups and fixes Cleanups and minor fixes in preparation for factoring out of read/write passthrough code. - Overlayfs lock ordering changes Hold mnt_writers only throughout copy up instead of a long lived elevated refcount. - Add support for nesting overlayfs private xattrs There are cases where you want to use an overlayfs mount as a lowerdir for another overlayfs mount. For example, if the system rootfs is on overlayfs due to composefs, or to make it volatile (via tmpfs), then you cannot currently store a lowerdir on the rootfs, because the inner overlayfs will eat all the whiteouts and overlay xattrs. This means you can't e.g. store on the rootfs a prepared container image for use with overlayfs. This adds support for nesting of overlayfs mounts by escaping the problematic features and unescaping them when exposing to the overlayfs user. - Add new mount options for appending lowerdirs * tag 'ovl-update-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs: ovl: add support for appending lowerdirs one by one ovl: refactor layer parsing helpers ovl: store and show the user provided lowerdir mount option ovl: remove unused code in lowerdir param parsing ovl: Add documentation on nesting of overlayfs mounts ovl: Add an alternative type of whiteout ovl: Support escaped overlay.* xattrs ovl: Add OVL_XATTR_TRUSTED/USER_PREFIX_LEN macros ovl: Move xattr support to new xattrs.c file ovl: do not encode lower fh with upper sb_writers held ovl: do not open/llseek lower file with upper sb_writers held ovl: reorder ovl_want_write() after ovl_inode_lock() ovl: split ovl_want_write() into two helpers ovl: add helper ovl_file_modified() ovl: protect copying of realinode attributes to ovl inode ovl: punt write aio completion to workqueue ovl: propagate IOCB_APPEND flag on writes to realfile ovl: use simpler function to convert iocb to rw flags

Merge tag 'erofs-for-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

2023-11-02T17:53:57+00:00

Pull erofs updates from Gao Xiang: "Nothing exciting lands for this cycle, since we're still busying in developing support for sub-page blocks and large-folios of compressed data for new scenarios on Android. In this cycle, MicroLZMA format is marked as stable, and there are minor cleanups around documentation and codebase. In addition, it also fixes incorrect lockref usage in erofs_insert_workgroup(). Summary: - Fix inode metadata space layout documentation - Avoid warning for MicroLZMA format anymore - Fix erofs_insert_workgroup() lockref usage - Some cleanups" * tag 'erofs-for-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs: erofs: fix erofs_insert_workgroup() lockref usage erofs: tidy up redundant includes erofs: get rid of ROOT_NID() erofs: simplify compression configuration parser erofs: don't warn MicroLZMA format anymore erofs: fix inode metadata space layout description in documentation

Merge tag 'docs-6.7' of git://git.lwn.net/linux

2023-11-02T03:11:41+00:00

Pull documentation updates from Jonathan Corbet: "The number of commits for documentation is not huge this time around, but there are some significant changes nonetheless: - Some more Spanish-language and Chinese translations - The much-discussed documentation of the confidential-computing threat model - Powerpc and RISCV documentation move under Documentation/arch - these complete this particular bit of documentation churn - A large traditional-Chinese documentation update - A new document on backporting and conflict resolution - Some kernel-doc and Sphinx fixes Plus the usual smattering of smaller updates and typo fixes" * tag 'docs-6.7' of git://git.lwn.net/linux: (40 commits) scripts/kernel-doc: Fix the regex for matching -Werror flag docs: backporting: address feedback Documentation: driver-api: pps: Update PPS generator documentation speakup: Document USB support doc: blk-ioprio: Bring the doc in line with the implementation docs: usb: fix reference to nonexistent file in UVC Gadget docs: doc-guide: mention 'make refcheckdocs' Documentation: fix typo in dynamic-debug howto scripts/kernel-doc: match -Werror flag strictly Documentation/sphinx: Remove the repeated word "the" in comments. docs: sparse: add SPDX-License-Identifier docs/zh_CN: Add subsystem-apis Chinese translation docs/zh_TW: update contents for zh_TW docs: submitting-patches: encourage direct notifications to commenters docs: add backporting and conflict resolution document docs: move riscv under arch docs: update link to powerpc/vmemmap_dedup.rst mm/memory-hotplug: fix typo in documentation docs: move powerpc under arch PCI: Update the devres documentation regarding to pcim_*() ...

Merge tag 'bootconfig-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2023-11-02T02:07:05+00:00

Pull bootconfig updates from Masami Hiramatsu: - Documentation update for /proc/cmdline, which includes both the parameters from bootloader and the embedded parameters in the kernel - fs/proc: Add bootloader argument as a comment line to /proc/bootconfig so that the user can distinguish what parameters were passed from bootloader even if bootconfig modified that - Documentation fix to add /proc/bootconfig to proc.rst * tag 'bootconfig-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: doc: Add /proc/bootconfig to proc.rst fs/proc: Add boot loader arguments as comment to /proc/bootconfig doc: Update /proc/cmdline documentation to include boot config

doc: Add /proc/bootconfig to proc.rst

2023-10-31T09:46:43+00:00

Add /proc/bootconfig description to Documentation/filesystems/proc.rst. Link: https://lore.kernel.org/all/20231005171747.541123-3-paulmck@kernel.org/ Reported-by: Masami Hiramatsu Signed-off-by: Paul E. McKenney Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google)