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2021-08-30Merge tag 'hole_punch_for_v5.15-rc1' of ↵HEADmasterLinus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull fs hole punching vs cache filling race fixes from Jan Kara: "Fix races leading to possible data corruption or stale data exposure in multiple filesystems when hole punching races with operations such as readahead. This is the series I was sending for the last merge window but with your objection fixed - now filemap_fault() has been modified to take invalidate_lock only when we need to create new page in the page cache and / or bring it uptodate" * tag 'hole_punch_for_v5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: filesystems/locking: fix Malformed table warning cifs: Fix race between hole punch and page fault ceph: Fix race between hole punch and page fault fuse: Convert to using invalidate_lock f2fs: Convert to using invalidate_lock zonefs: Convert to using invalidate_lock xfs: Convert double locking of MMAPLOCK to use VFS helpers xfs: Convert to use invalidate_lock xfs: Refactor xfs_isilocked() ext2: Convert to using invalidate_lock ext4: Convert to use mapping->invalidate_lock mm: Add functions to lock invalidate_lock for two mappings mm: Protect operations adding pages to page cache with invalidate_lock documentation: Sync file_operations members with reality mm: Fix comments mentioning i_mutex
2021-07-28filesystems/locking: fix Malformed table warningRandy Dunlap
Update the bottom border to be the same as the top border. Documentation/filesystems/locking.rst:274: WARNING: Malformed table. Bottom/header table border does not match top border. Fixes: 730633f0b7f9 ("mm: Protect operations adding pages to page cache with invalidate_lock") Link: https://lore.kernel.org/r/20210727232212.12510-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.cz> Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz>
2021-07-18Documentation: Fix intiramfs script nameRobert Richter
Documentation was not changed when renaming the script in commit 80e715a06c2d ("initramfs: rename gen_initramfs_list.sh to gen_initramfs.sh"). Fixing this. Basically does: $ sed -i -e s/gen_initramfs_list.sh/gen_initramfs.sh/g $(git grep -l gen_initramfs_list.sh) Fixes: 80e715a06c2d ("initramfs: rename gen_initramfs_list.sh to gen_initramfs.sh") Signed-off-by: Robert Richter <rrichter@amd.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-07-13mm: Protect operations adding pages to page cache with invalidate_lockJan Kara
Currently, serializing operations such as page fault, read, or readahead against hole punching is rather difficult. The basic race scheme is like: fallocate(FALLOC_FL_PUNCH_HOLE) read / fault / .. truncate_inode_pages_range() <create pages in page cache here> <update fs block mapping and free blocks> Now the problem is in this way read / page fault / readahead can instantiate pages in page cache with potentially stale data (if blocks get quickly reused). Avoiding this race is not simple - page locks do not work because we want to make sure there are *no* pages in given range. inode->i_rwsem does not work because page fault happens under mmap_sem which ranks below inode->i_rwsem. Also using it for reads makes the performance for mixed read-write workloads suffer. So create a new rw_semaphore in the address_space - invalidate_lock - that protects adding of pages to page cache for page faults / reads / readahead. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2021-07-13documentation: Sync file_operations members with realityJan Kara
Sync listing of struct file_operations members with the real one in fs.h. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2021-07-09Merge tag 'f2fs-for-5.14-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs Pull f2fs updates from Jaegeuk Kim: "In this round, we've improved the compression support especially for Android such as allowing compression for mmap files, replacing the immutable bit with internal bit to prohibits data writes explicitly, and adding a mount option, "compress_cache", to improve random reads. And, we added "readonly" feature to compact the partition w/ compression enabled, which will be useful for Android RO partitions. Enhancements: - support compression for mmap file - use an f2fs flag instead of IMMUTABLE bit for compression - support RO feature w/ extent_cache - fully support swapfile with file pinning - improve atgc tunability - add nocompress extensions to unselect files for compression Bug fixes: - fix false alaram on iget failure during GC - fix race condition on global pointers when there are multiple f2fs instances - add MODULE_SOFTDEP for initramfs As usual, we've also cleaned up some places for better code readability (e.g., sysfs/feature, debugging messages, slab cache name, and docs)" * tag 'f2fs-for-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (32 commits) f2fs: drop dirty node pages when cp is in error status f2fs: initialize page->private when using for our internal use f2fs: compress: add nocompress extensions support MAINTAINERS: f2fs: update my email address f2fs: remove false alarm on iget failure during GC f2fs: enable extent cache for compression files in read-only f2fs: fix to avoid adding tab before doc section f2fs: introduce f2fs_casefolded_name slab cache f2fs: swap: support migrating swapfile in aligned write mode f2fs: swap: remove dead codes f2fs: compress: add compress_inode to cache compressed blocks f2fs: clean up /sys/fs/f2fs/<disk>/features f2fs: add pin_file in feature list f2fs: Advertise encrypted casefolding in sysfs f2fs: Show casefolding support only when supported f2fs: support RO feature f2fs: logging neatening f2fs: introduce FI_COMPRESS_RELEASED instead of using IMMUTABLE bit f2fs: compress: remove unneeded preallocation f2fs: atgc: export entries for better tunability via sysfs ...
2021-07-05Merge tag 'driver-core-5.14-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core changes from Greg KH: "Here is the small set of driver core and debugfs updates for 5.14-rc1. Included in here are: - debugfs api cleanups (touched some drivers) - devres updates - tiny driver core updates and tweaks Nothing major in here at all, and all have been in linux-next for a while with no reported issues" * tag 'driver-core-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (27 commits) docs: ABI: testing: sysfs-firmware-memmap: add some memmap types. devres: Enable trace events devres: No need to call remove_nodes() when there none present devres: Use list_for_each_safe_from() in remove_nodes() devres: Make locking straight forward in release_nodes() kernfs: move revalidate to be near lookup drivers/base: Constify static attribute_group structs firmware_loader: remove unneeded 'comma' macro devcoredump: remove contact information driver core: Drop helper devm_platform_ioremap_resource_wc() component: Rename 'dev' to 'parent' component: Drop 'dev' argument to component_match_realloc() device property: Don't check for NULL twice in the loops driver core: auxiliary bus: Fix typo in the docs drivers/base/node.c: make CACHE_ATTR define static DEVICE_ATTR_RO debugfs: remove return value of debugfs_create_ulong() debugfs: remove return value of debugfs_create_bool() scsi: snic: debugfs: remove local storage of debugfs files b43: don't save dentries for debugfs b43legacy: don't save dentries for debugfs ...
2021-07-03Merge branch 'work.namei' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs name lookup updates from Al Viro: "Small namei.c patch series, mostly to simplify the rules for nameidata state. It's actually from the previous cycle - but I didn't post it for review in time... Changes visible outside of fs/namei.c: file_open_root() calling conventions change, some freed bits in LOOKUP_... space" * 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: namei: make sure nd->depth is always valid teach set_nameidata() to handle setting the root as well take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space switch file_open_root() to struct path
2021-07-03Merge branch 'work.iov_iter' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull iov_iter updates from Al Viro: "iov_iter cleanups and fixes. There are followups, but this is what had sat in -next this cycle. IMO the macro forest in there became much thinner and easier to follow..." * 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits) csum_and_copy_to_pipe_iter(): leave handling of csum_state to caller clean up copy_mc_pipe_to_iter() pipe_zero(): we don't need no stinkin' kmap_atomic()... iov_iter: clean csum_and_copy_...() primitives up a bit copy_page_from_iter(): don't need kmap_atomic() for kvec/bvec cases copy_page_to_iter(): don't bother with kmap_atomic() for bvec/kvec cases iterate_xarray(): only of the first iteration we might get offset != 0 pull handling of ->iov_offset into iterate_{iovec,bvec,xarray} iov_iter: make iterator callbacks use base and len instead of iovec iov_iter: make the amount already copied available to iterator callbacks iov_iter: get rid of separate bvec and xarray callbacks iov_iter: teach iterate_{bvec,xarray}() about possible short copies iterate_bvec(): expand bvec.h macro forest, massage a bit iov_iter: unify iterate_iovec and iterate_kvec iov_iter: massage iterate_iovec and iterate_kvec to logics similar to iterate_bvec iterate_and_advance(): get rid of magic in case when n is 0 csum_and_copy_to_iter(): massage into form closer to csum_and_copy_from_iter() iov_iter: replace iov_iter_copy_from_user_atomic() with iterator-advancing variant [xarray] iov_iter_npages(): just use DIV_ROUND_UP() iov_iter_npages(): don't bother with iterate_all_kinds() ...
2021-07-02Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge more updates from Andrew Morton: "190 patches. Subsystems affected by this patch series: mm (hugetlb, userfaultfd, vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock, migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap, zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc, core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs, signals, exec, kcov, selftests, compress/decompress, and ipc" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits) ipc/util.c: use binary search for max_idx ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock ipc: use kmalloc for msg_queue and shmid_kernel ipc sem: use kvmalloc for sem_undo allocation lib/decompressors: remove set but not used variabled 'level' selftests/vm/pkeys: exercise x86 XSAVE init state selftests/vm/pkeys: refill shadow register after implicit kernel write selftests/vm/pkeys: handle negative sys_pkey_alloc() return code selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random kcov: add __no_sanitize_coverage to fix noinstr for all architectures exec: remove checks in __register_bimfmt() x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned hfsplus: report create_date to kstat.btime hfsplus: remove unnecessary oom message nilfs2: remove redundant continue statement in a while-loop kprobes: remove duplicated strong free_insn_page in x86 and s390 init: print out unknown kernel parameters checkpatch: do not complain about positive return values starting with EPOLL checkpatch: improve the indented label test checkpatch: scripts/spdxcheck.py now requires python3 ...
2021-07-01f2fs: compress: add nocompress extensions supportFengnan Chang
When we create a directory with enable compression, all file write into directory will try to compress.But sometimes we may know, new file cannot meet compression ratio requirements. We need a nocompress extension to skip those files to avoid unnecessary compress page test. After add nocompress_extension, the priority should be: dir_flag < comp_extention,nocompress_extension < comp_file_flag, no_comp_file_flag. Priority in between FS_COMPR_FL, FS_NOCOMP_FS, extensions: * compress_extension=so; nocompress_extension=zip; chattr +c dir; touch dir/foo.so; touch dir/bar.zip; touch dir/baz.txt; then foo.so and baz.txt should be compresse, bar.zip should be non-compressed. chattr +c dir/bar.zip can enable compress on bar.zip. * compress_extension=so; nocompress_extension=zip; chattr -c dir; touch dir/foo.so; touch dir/bar.zip; touch dir/baz.txt; then foo.so should be compresse, bar.zip and baz.txt should be non-compressed. chattr+c dir/bar.zip; chattr+c dir/baz.txt; can enable compress on bar.zip and baz.txt. Signed-off-by: Fengnan Chang <changfengnan@vivo.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2021-07-01procfs/dmabuf: add inode number to /proc/*/fdinfoKalesh Singh
And 'ino' field to /proc/<pid>/fdinfo/<FD> and /proc/<pid>/task/<tid>/fdinfo/<FD>. The inode numbers can be used to uniquely identify DMA buffers in user space and avoids a dependency on /proc/<pid>/fd/* when accounting per-process DMA buffer sizes. Link: https://lkml.kernel.org/r/20210308170651.919148-2-kaleshsingh@google.com Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Christian König <christian.koenig@amd.com> Cc: Jann Horn <jannh@google.com> Cc: Jeff Vander Stoep <jeffv@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Hridya Valsaraju <hridya@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Alexey Gladkov <gladkov.alexey@gmail.com> Cc: Szabolcs Nagy <szabolcs.nagy@arm.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Bernd Edlinger <bernd.edlinger@hotmail.de> Cc: Andrei Vagin <avagin@gmail.com> Cc: Helge Deller <deller@gmx.de> Cc: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30docs: proc.rst: meminfo: briefly describe gaps in memory accountingMike Rapoport
Add a paragraph that explains that it may happen that the counters in /proc/meminfo do not add up to the overall memory usage. Link: https://lkml.kernel.org/r/20210421061127.1182723-1-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30Merge tag 'ext4_for_linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "In addition to bug fixes and cleanups, there are two new features for ext4 in 5.14: - Allow applications to poll on changes to /sys/fs/ext4/*/errors_count - Add the ioctl EXT4_IOC_CHECKPOINT which allows the journal to be checkpointed, truncated and discarded or zero'ed" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (32 commits) jbd2: export jbd2_journal_[un]register_shrinker() ext4: notify sysfs on errors_count value change fs: remove bdev_try_to_free_page callback ext4: remove bdev_try_to_free_page() callback jbd2: simplify journal_clean_one_cp_list() jbd2,ext4: add a shrinker to release checkpointed buffers jbd2: remove redundant buffer io error checks jbd2: don't abort the journal when freeing buffers jbd2: ensure abort the journal if detect IO error when writing original buffer back jbd2: remove the out label in __jbd2_journal_remove_checkpoint() ext4: no need to verify new add extent block jbd2: clean up misleading comments for jbd2_fc_release_bufs ext4: add check to prevent attempting to resize an fs with sparse_super2 ext4: consolidate checks for resize of bigalloc into ext4_resize_begin ext4: remove duplicate definition of ext4_xattr_ibody_inline_set() ext4: fsmap: fix the block/inode bitmap comment ext4: fix comment for s_hash_unsigned ext4: use local variable ei instead of EXT4_I() macro ext4: fix avefreec in find_group_orlov ext4: correct the cache_nr in tracepoint ext4_es_shrink_exit ...
2021-06-30Merge tag 'for-5.14/block-2021-06-29' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull core block updates from Jens Axboe: - disk events cleanup (Christoph) - gendisk and request queue allocation simplifications (Christoph) - bdev_disk_changed cleanups (Christoph) - IO priority improvements (Bart) - Chained bio completion trace fix (Edward) - blk-wbt fixes (Jan) - blk-wbt enable/disable fix (Zhang) - Scheduler dispatch improvements (Jan, Ming) - Shared tagset scheduler improvements (John) - BFQ updates (Paolo, Luca, Pietro) - BFQ lock inversion fix (Jan) - Documentation improvements (Kir) - CLONE_IO block cgroup fix (Tejun) - Remove of ancient and deprecated block dump feature (zhangyi) - Discard merge fix (Ming) - Misc fixes or followup fixes (Colin, Damien, Dan, Long, Max, Thomas, Yang) * tag 'for-5.14/block-2021-06-29' of git://git.kernel.dk/linux-block: (129 commits) block: fix discard request merge block/mq-deadline: Remove a WARN_ON_ONCE() call blk-mq: update hctx->dispatch_busy in case of real scheduler blk: Fix lock inversion between ioc lock and bfqd lock bfq: Remove merged request already in bfq_requests_merged() block: pass a gendisk to bdev_disk_changed block: move bdev_disk_changed block: add the events* attributes to disk_attrs block: move the disk events code to a separate file block: fix trace completion for chained bio block/partitions/msdos: Fix typo inidicator -> indicator block, bfq: reset waker pointer with shared queues block, bfq: check waker only for queues with no in-flight I/O block, bfq: avoid delayed merge of async queues block, bfq: boost throughput by extending queue-merging times block, bfq: consider also creation time in delayed stable merge block, bfq: fix delayed stable merge check block, bfq: let also stably merged queues enjoy weight raising blk-wbt: make sure throttle is enabled properly blk-wbt: introduce a new disable state to prevent false positive by rwb_enabled() ...
2021-06-28Merge tag 'docs-5.14' of git://git.lwn.net/linuxLinus Torvalds
Pull documentation updates from Jonathan Corbet: "This was a reasonably active cycle for documentation; this includes: - Some kernel-doc cleanups. That script is still regex onslaught from hell, but it has gotten a little better. - Improvements to the checkpatch docs, which are also used by the tool itself. - A major update to the pathname lookup documentation. - Elimination of :doc: markup, since our automarkup magic can create references from filenames without all the extra noise. - The flurry of Chinese translation activity continues. Plus, of course, the usual collection of updates, typo fixes, and warning fixes" * tag 'docs-5.14' of git://git.lwn.net/linux: (115 commits) docs: path-lookup: use bare function() rather than literals docs: path-lookup: update symlink description docs: path-lookup: update get_link() ->follow_link description docs: path-lookup: update WALK_GET, WALK_PUT desc docs: path-lookup: no get_link() docs: path-lookup: update i_op->put_link and cookie description docs: path-lookup: i_op->follow_link replaced with i_op->get_link docs: path-lookup: Add macro name to symlink limit description docs: path-lookup: remove filename_mountpoint docs: path-lookup: update do_last() part docs: path-lookup: update path_mountpoint() part docs: path-lookup: update path_to_nameidata() part docs: path-lookup: update follow_managed() part docs: Makefile: Use CONFIG_SHELL not SHELL docs: Take a little noise out of the build process docs: x86: avoid using ReST :doc:`foo` markup docs: virt: kvm: s390-pv-boot.rst: avoid using ReST :doc:`foo` markup docs: userspace-api: landlock.rst: avoid using ReST :doc:`foo` markup docs: trace: ftrace.rst: avoid using ReST :doc:`foo` markup docs: trace: coresight: coresight.rst: avoid using ReST :doc:`foo` markup ...
2021-06-23f2fs: fix to avoid adding tab before doc sectionChao Yu
Otherwise whole section after tab will be invisible in compiled html format document. Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Fixes: 89272ca1102e ("docs: filesystems: convert f2fs.txt to ReST") Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2021-06-23f2fs: compress: add compress_inode to cache compressed blocksChao Yu
Support to use address space of inner inode to cache compressed block, in order to improve cache hit ratio of random read. Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2021-06-22ext4: update journal documentationLeah Rumancik
Add a section about journal checkpointing, including information about the ioctl EXT4_IOC_CHECKPOINT which can be used to trigger a journal checkpoint from userspace. Also, update the journal allocation information to reflect that up to 10240000 blocks are used for the journal and that the journal is not necessarily contiguous. Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com> Changes in v5: - clarify behavior of DRY_RUN flag Link: https://lore.kernel.org/r/20210518151327.130198-3-leah.rumancik@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-06-18docs: path-lookup: use bare function() rather than literalsFox Chen
As suggested by Matthew Wilcox and Jonathan Corbet, drop ``...`` literals around function names of this patchset. Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-14-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: update symlink descriptionFox Chen
instead of lookup_real()/vfs_create(), i_op->lookup() and i_op->create() will be called directly. update vfs_open() logic should_follow_link is merged into lookup_last() or open_last_lookup() which returns symlink name instead of an integer. Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-13-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: update get_link() ->follow_link descriptionFox Chen
get_link() is merged into pick_link(). i_op->follow_link is replaced with i_op->get_link(). get_link() can return ERR_PTR(0) which equals NULL. Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-12-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: update WALK_GET, WALK_PUT descFox Chen
WALK_GET is changed to WALK_TRAILING with a different meaning. Here it should be WALK_NOFOLLOW. WALK_PUT dosn't exist, we have WALK_MORE. WALK_PUT == !WALK_MORE And there is not should_follow_link(). Related commits: commit 8c4efe22e7c4 ("namei: invert the meaning of WALK_FOLLOW") commit 1c4ff1a87e46 ("namei: invert WALK_PUT logics") Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> [jc: applied language tweaks suggested by Neil] Link: https://lore.kernel.org/r/20210527091618.287093-11-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: no get_link()Fox Chen
no get_link() anymore. we have step_into() and pick_link(). walk_component() will call step_into(), in turn call pick_link, and return symlink name. Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-10-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: update i_op->put_link and cookie descriptionFox Chen
No inode->put_link operation anymore. We use delayed_call to deal with link destruction. Cookie has been replaced with struct delayed_call. Related commit: commit fceef393a538 ("switch ->get_link() to delayed_call, kill ->put_link()") Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-9-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: i_op->follow_link replaced with i_op->get_linkFox Chen
follow_link has been replaced by get_link() which can be called in RCU mode. see commit: commit 6b2553918d8b ("replace ->follow_link() with new method that could stay in RCU mode") Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-8-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: Add macro name to symlink limit descriptionFox Chen
Add macro name MAXSYMLINKS to the symlink limit description, so that it is consistent with path name length description above. Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-7-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: remove filename_mountpointFox Chen
No filename_mountpoint any more see commit: commit 161aff1d93ab ("LOOKUP_MOUNTPOINT: fold path_mountpointat() into path_lookupat()") Without filename_mountpoint and path_mountpoint(), the numbers should be four & three: "These four correspond roughly to the three path_*() functions" Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-6-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: update do_last() partFox Chen
traling_symlink() was merged into lookup_last, do_last(). do_last() has later been split into open_last_lookups() and do_open(). see related commit: commit c5971b8c6354 ("take post-lookup part of do_last() out of loop") Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-5-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: update path_mountpoint() partFox Chen
path_mountpoint() doesn't exist anymore. Have been folded into path_lookup_at when flag is set with LOOKUP_MOUNTPOINT. Check commit: commit 161aff1d93abf0e ("LOOKUP_MOUNTPOINT: fold path_mountpointat() into path_lookupat()") Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-4-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: update path_to_nameidata() partFox Chen
No path_to_namei() anymore, step_into() will be called. Related commit: commit c99687a03a78 ("fold path_to_nameidata() into its only remaining caller") Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-3-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-18docs: path-lookup: update follow_managed() partFox Chen
No follow_managed() anymore, handle_mounts(), traverse_mounts(), will do the job. see commit 9deed3ebca24 ("new helper: traverse_mounts()") Signed-off-by: Fox Chen <foxhlchen@gmail.com> Reviewed-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20210527091618.287093-2-foxhlchen@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-17docs: filesystems: ext4: blockgroup.rst: replace some charactersMauro Carvalho Chehab
The conversion tools used during DocBook/LaTeX/html/Markdown->ReST conversion and some cut-and-pasted text contain some characters that aren't easily reachable on standard keyboards and/or could cause troubles when parsed by the documentation build system. Replace the occurences of the following characters: - U+2217 ('∗'): ASTERISK OPERATOR use ASCII asterisk instead of the ASTERISK OPERATOR Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Acked-by: Theodore Ts'o <tytso@mit.edu> Link: https://lore.kernel.org/r/c5c3c384c48779ca7c9dcd90183cefe20ac82928.1623826294.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-13docs: fix a cross-refKir Kolyshkin
Commit acda97acb2e98c9 changes dax.txt to dax.rst. Fix the references accordingly. Cc: Igor Matheus Andrade Torrente <igormtorrente@gmail.com> Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com> Link: https://lore.kernel.org/r/20210611030044.1982911-4-kolyshkin@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-10iov_iter: replace iov_iter_copy_from_user_atomic() with iterator-advancing ↵Al Viro
variant Replacement is called copy_page_from_iter_atomic(); unlike the old primitive the callers do *not* need to do iov_iter_advance() after it. In case when they end up consuming less than they'd been given they need to do iov_iter_revert() on everything they had not consumed. That, however, needs to be done only on slow paths. All in-tree callers converted. And that kills the last user of iterate_all_kinds() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-06-04docs: convert dax.txt to rstIgor Matheus Andrade Torrente
Change the file extension and add the rst constructs to integrate this doc to the documentation infrastructure and take advantage of rst features. Signed-off-by: Igor Matheus Andrade Torrente <igormtorrente@gmail.com> Link: https://lore.kernel.org/r/20210531130515.10309-1-igormtorrente@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-01block: move bd_mutex to struct gendiskChristoph Hellwig
Replace the per-block device bd_mutex with a per-gendisk open_mutex, thus simplifying locking wherever we deal with partitions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Link: https://lore.kernel.org/r/20210525061301.2242282-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-21debugfs: remove return value of debugfs_create_bool()Greg Kroah-Hartman
No one checks the return value of debugfs_create_bool(), as it's not needed, so make the return value void, so that no one tries to do so in the future. Link: https://lore.kernel.org/r/20210521184519.1356639-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-11erofs: update documentation about data compressionGao Xiang
Add more description about (NON)HEAD lclusters, and the new big pcluster feature. Link: https://lore.kernel.org/r/20210511084414.21305-1-xiang@kernel.org Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <xiang@kernel.org>
2021-05-11erofs: fix broken illustration in documentationGao Xiang
Illustration was broken after ReST conversion by accident. (checked by 'make SPHINXDIRS="filesystems" htmldocs') Link: https://lore.kernel.org/r/20210510162506.28637-1-xiang@kernel.org Fixes: e66d8631ddb3 ("docs: filesystems: convert erofs.txt to ReST") Reviewed-by: Chao Yu <yuchao0@huawei.com> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Gao Xiang <xiang@kernel.org>
2021-05-04Merge tag 'f2fs-for-5.13-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs Pull f2fs updates from Jaegeuk Kim: "In this round, we added a new mount option, "checkpoint_merge", which introduces a kernel thread dealing with the f2fs checkpoints. Once we start to manage the IO priority along with blk-cgroup, the checkpoint operation can be processed in a lower priority under the process context. Since the checkpoint holds all the filesystem operations, we give a higher priority to the checkpoint thread all the time. Enhancements: - introduce gc_merge mount option to introduce a checkpoint thread - improve to run discard thread efficiently - allow modular compression algorithms - expose # of overprivision segments to sysfs - expose runtime compression stat to sysfs Bug fixes: - fix OOB memory access by the node id lookup - avoid touching checkpointed data in the checkpoint-disabled mode - fix the resizing flow to avoid kernel panic and race conditions - fix block allocation issues on pinned files - address some swapfile issues - fix hugtask problem and kernel panic during atomic write operations - don't start checkpoint thread in RO And, we've cleaned up some kernel coding style and build warnings. In addition, we fixed some minor race conditions and error handling routines" * tag 'f2fs-for-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (48 commits) f2fs: drop inplace IO if fs status is abnormal f2fs: compress: remove unneed check condition f2fs: clean up left deprecated IO trace codes f2fs: avoid using native allocate_segment_by_default() f2fs: remove unnecessary struct declaration f2fs: fix to avoid NULL pointer dereference f2fs: avoid duplicated codes for cleanup f2fs: document: add description about compressed space handling f2fs: clean up build warnings f2fs: fix the periodic wakeups of discard thread f2fs: fix to avoid accessing invalid fio in f2fs_allocate_data_block() f2fs: fix to avoid GC/mmap race with f2fs_truncate() f2fs: set checkpoint_merge by default f2fs: Fix a hungtask problem in atomic write f2fs: fix to restrict mount condition on readonly block device f2fs: introduce gc_merge mount option f2fs: fix to cover __allocate_new_section() with curseg_lock f2fs: fix wrong alloc_type in f2fs_do_replace_block f2fs: delete empty compress.h f2fs: fix a typo in inode.c ...
2021-04-30Merge tag 'ext4_for_linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "New features for ext4 this cycle include support for encrypted casefold, ensure that deleted file names are cleared in directory blocks by zeroing directory entries when they are unlinked or moved as part of a hash tree node split. We also improve the block allocator's performance on a freshly mounted file system by prefetching block bitmaps. There are also the usual cleanups and bug fixes, including fixing a page cache invalidation race when there is mixed buffered and direct I/O and the block size is less than page size, and allow the dax flag to be set and cleared on inline directories" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (32 commits) ext4: wipe ext4_dir_entry2 upon file deletion ext4: Fix occasional generic/418 failure fs: fix reporting supported extra file attributes for statx() ext4: allow the dax flag to be set and cleared on inline directories ext4: fix debug format string warning ext4: fix trailing whitespace ext4: fix various seppling typos ext4: fix error return code in ext4_fc_perform_commit() ext4: annotate data race in jbd2_journal_dirty_metadata() ext4: annotate data race in start_this_handle() ext4: fix ext4_error_err save negative errno into superblock ext4: fix error code in ext4_commit_super ext4: always panic when errors=panic is specified ext4: delete redundant uptodate check for buffer ext4: do not set SB_ACTIVE in ext4_orphan_cleanup() ext4: make prefetch_block_bitmaps default ext4: add proc files to monitor new structures ext4: improve cr 0 / cr 1 group scanning ext4: add MB_NUM_ORDERS macro ext4: add mballoc stats proc file ...
2021-04-30Merge tag 'ovl-update-5.13' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs update from Miklos Szeredi: - Fix a regression introduced in 5.2 that resulted in valid overlayfs mounts being rejected with ELOOP (Too many levels of symbolic links) - Fix bugs found by various tools - Miscellaneous improvements and cleanups * tag 'ovl-update-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: add debug print to ovl_do_getxattr() ovl: invalidate readdir cache on changes to dir with origin ovl: allow upperdir inside lowerdir ovl: show "userxattr" in the mount data ovl: trivial typo fixes in the file inode.c ovl: fix misspellings using codespell tool ovl: do not copy attr several times ovl: remove ovl_map_dev_ino() return value ovl: fix error for ovl_fill_super() ovl: fix missing revert_creds() on error path ovl: fix leaked dentry ovl: restrict lower null uuid for "xino=auto" ovl: check that upperdir path is not on a read-only mount ovl: plumb through flush method
2021-04-28Merge tag 'for-5.13/drivers-2021-04-27' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block driver updates from Jens Axboe: - MD changes via Song: - raid5 POWER fix - raid1 failure fix - UAF fix for md cluster - mddev_find_or_alloc() clean up - Fix NULL pointer deref with external bitmap - Performance improvement for raid10 discard requests - Fix missing information of /proc/mdstat - rsxx const qualifier removal (Arnd) - Expose allocated brd pages (Calvin) - rnbd via Gioh Kim: - Change maintainer - Change domain address of maintainers' email - Add polling IO mode and document update - Fix memory leak and some bug detected by static code analysis tools - Code refactoring - Series of floppy cleanups/fixes (Denis) - s390 dasd fixes (Julian) - kerneldoc fixes (Lee) - null_blk double free (Lv) - null_blk virtual boundary addition (Max) - Remove xsysace driver (Michal) - umem driver removal (Davidlohr) - ataflop fixes (Dan) - Revalidate disk removal (Christoph) - Bounce buffer cleanups (Christoph) - Mark lightnvm as deprecated (Christoph) - mtip32xx init cleanups (Shixin) - Various fixes (Tian, Gustavo, Coly, Yang, Zhang, Zhiqiang) * tag 'for-5.13/drivers-2021-04-27' of git://git.kernel.dk/linux-block: (143 commits) async_xor: increase src_offs when dropping destination page drivers/block/null_blk/main: Fix a double free in null_init. md/raid1: properly indicate failure when ending a failed write request md-cluster: fix use-after-free issue when removing rdev nvme: introduce generic per-namespace chardev nvme: cleanup nvme_configure_apst nvme: do not try to reconfigure APST when the controller is not live nvme: add 'kato' sysfs attribute nvme: sanitize KATO setting nvmet: avoid queuing keep-alive timer if it is disabled brd: expose number of allocated pages in debugfs ataflop: fix off by one in ataflop_probe() ataflop: potential out of bounds in do_format() drbd: Fix fall-through warnings for Clang block/rnbd: Use strscpy instead of strlcpy block/rnbd-clt-sysfs: Remove copy buffer overlap in rnbd_clt_get_path_name block/rnbd-clt: Remove max_segment_size block/rnbd-clt: Generate kobject_uevent when the rnbd device state changes block/rnbd-srv: Remove unused arguments of rnbd_srv_rdma_ev Documentation/ABI/rnbd-clt: Add description for nr_poll_queues ...
2021-04-27Merge tag 'netfs-lib-20210426' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull network filesystem helper library updates from David Howells: "Here's a set of patches for 5.13 to begin the process of overhauling the local caching API for network filesystems. This set consists of two parts: (1) Add a helper library to handle the new VM readahead interface. This is intended to be used unconditionally by the filesystem (whether or not caching is enabled) and provides a common framework for doing caching, transparent huge pages and, in the future, possibly fscrypt and read bandwidth maximisation. It also allows the netfs and the cache to align, expand and slice up a read request from the VM in various ways; the netfs need only provide a function to read a stretch of data to the pagecache and the helper takes care of the rest. (2) Add an alternative fscache/cachfiles I/O API that uses the kiocb facility to do async DIO to transfer data to/from the netfs's pages, rather than using readpage with wait queue snooping on one side and vfs_write() on the other. It also uses less memory, since it doesn't do buffered I/O on the backing file. Note that this uses SEEK_HOLE/SEEK_DATA to locate the data available to be read from the cache. Whilst this is an improvement from the bmap interface, it still has a problem with regard to a modern extent-based filesystem inserting or removing bridging blocks of zeros. Fixing that requires a much greater overhaul. This is a step towards overhauling the fscache API. The change is opt-in on the part of the network filesystem. A netfs should not try to mix the old and the new API because of conflicting ways of handling pages and the PG_fscache page flag and because it would be mixing DIO with buffered I/O. Further, the helper library can't be used with the old API. This does not change any of the fscache cookie handling APIs or the way invalidation is done at this time. In the near term, I intend to deprecate and remove the old I/O API (fscache_allocate_page{,s}(), fscache_read_or_alloc_page{,s}(), fscache_write_page() and fscache_uncache_page()) and eventually replace most of fscache/cachefiles with something simpler and easier to follow. This patchset contains the following parts: - Some helper patches, including provision of an ITER_XARRAY iov iterator and a function to do readahead expansion. - Patches to add the netfs helper library. - A patch to add the fscache/cachefiles kiocb API. - A pair of patches to fix some review issues in the ITER_XARRAY and read helpers as spotted by Al and Willy. Jeff Layton has patches to add support in Ceph for this that he intends for this merge window. I have a set of patches to support AFS that I will post a separate pull request for. With this, AFS without a cache passes all expected xfstests; with a cache, there's an extra failure, but that's also there before these patches. Fixing that probably requires a greater overhaul. Ceph also passes the expected tests. I also have patches in a separate branch to tidy up the handling of PG_fscache/PG_private_2 and their contribution to page refcounting in the core kernel here, but I haven't included them in this set and will route them separately" Link: https://lore.kernel.org/lkml/3779937.1619478404@warthog.procyon.org.uk/ * tag 'netfs-lib-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: netfs: Miscellaneous fixes iov_iter: Four fixes for ITER_XARRAY fscache, cachefiles: Add alternate API to use kiocb for read/write to cache netfs: Add a tracepoint to log failures that would be otherwise unseen netfs: Define an interface to talk to a cache netfs: Add write_begin helper netfs: Gather stats netfs: Add tracepoints netfs: Provide readahead and readpage netfs helpers netfs, mm: Add set/end/wait_on_page_fscache() aliases netfs, mm: Move PG_fscache helper funcs to linux/netfs.h netfs: Documentation for helper library netfs: Make a netfs helper module mm: Implement readahead_control pageset expansion mm/readahead: Handle ractl nr_pages being modified fs: Document file_ra_state mm/filemap: Pass the file_ra_state in the ractl mm: Add set/end/wait functions for PG_private_2 iov_iter: Add ITER_XARRAY
2021-04-27Merge branch 'miklos.fileattr' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull fileattr conversion updates from Miklos Szeredi via Al Viro: "This splits the handling of FS_IOC_[GS]ETFLAGS from ->ioctl() into a separate method. The interface is reasonably uniform across the filesystems that support it and gives nice boilerplate removal" * 'miklos.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (23 commits) ovl: remove unneeded ioctls fuse: convert to fileattr fuse: add internal open/release helpers fuse: unsigned open flags fuse: move ioctl to separate source file vfs: remove unused ioctl helpers ubifs: convert to fileattr reiserfs: convert to fileattr ocfs2: convert to fileattr nilfs2: convert to fileattr jfs: convert to fileattr hfsplus: convert to fileattr efivars: convert to fileattr xfs: convert to fileattr orangefs: convert to fileattr gfs2: convert to fileattr f2fs: convert to fileattr ext4: convert to fileattr ext2: convert to fileattr btrfs: convert to fileattr ...
2021-04-23netfs: Documentation for helper libraryDavid Howells
Add interface documentation for the netfs helper library. Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-mm@kvack.org cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/161539533275.286939.6246011228676840978.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653791767.2770958.2012814194145060913.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789072591.6155.9448294406920216219.stgit@warthog.procyon.org.uk/ # v6
2021-04-13f2fs: document: add description about compressed space handlingChao Yu
User or developer may still be confused about why f2fs doesn't expose compressed space to userspace, add description about compressed space handling policy into f2fs documentation. Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2021-04-12vfs: add fileattr opsMiklos Szeredi
There's a substantial amount of boilerplate in filesystems handling FS_IOC_[GS]ETFLAGS/ FS_IOC_FS[GS]ETXATTR ioctls. Also due to userspace buffers being involved in the ioctl API this is difficult to stack, as shown by overlayfs issues related to these ioctls. Introduce a new internal API named "fileattr" (fsxattr can be confused with xattr, xflags is inappropriate, since this is more than just flags). There's significant overlap between flags and xflags and this API handles the conversions automatically, so filesystems may choose which one to use. In ->fileattr_get() a hint is provided to the filesystem whether flags or xattr are being requested by userspace, but in this series this hint is ignored by all filesystems, since generating all the attributes is cheap. If a filesystem doesn't implemement the fileattr API, just fall back to f_op->ioctl(). When all filesystems are converted, the fallback can be removed. 32bit compat ioctls are now handled by the generic code as well. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-04-12ovl: restrict lower null uuid for "xino=auto"Amir Goldstein
Commit a888db310195 ("ovl: fix regression with re-formatted lower squashfs") attempted to fix a regression with existing setups that use a practice that we are trying to discourage. The discourage part was described this way in the commit message: "To avoid the reported regression while still allowing the new features with single lower squashfs, do not allow decoding origin with lower null uuid unless user opted-in to one of the new features that require following the lower inode of non-dir upper (index, xino, metacopy)." The three mentioned features are disabled by default in Kconfig, so it was assumed that if they are enabled, the user opted-in for them. Apparently, distros started to configure CONFIG_OVERLAY_FS_XINO_AUTO=y some time ago, so users upgrading their kernels can still be affected by said regression even though they never opted-in for any new feature. To fix this, treat "xino=on" as "user opted-in", but not "xino=auto". Since we are changing the behavior of "xino=auto" to no longer follow to lower origin with null uuid, take this one step further and disable xino in that corner case. To be consistent, disable xino also in cases of lower fs without file handle support and upper fs without xattr support. Update documentation w.r.t the new "xino=auto" behavior and fix the out dated bits of documentation regarding "xino" and regarding offline modifications to lower layers. Link: https://lore.kernel.org/linux-unionfs/b36a429d7c563730c28d763d4d57a6fc30508a4f.1615216996.git.kevin@kevinlocke.name/ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>