kernel.git/fs/ext4/file.c, branch linux-5.12.y

ext4: Fix occasional generic/418 failure

2021-05-12T06:40:01Z

commit 5899593f51e63dde2f07c67358bd65a641585abb upstream. Eric has noticed that after pagecache read rework, generic/418 is occasionally failing for ext4 when blocksize < pagesize. In fact, the pagecache rework just made hard to hit race in ext4 more likely. The problem is that since ext4 conversion of direct IO writes to iomap framework (commit 378f32bab371), we update inode size after direct IO write only after invalidating page cache. Thus if buffered read sneaks at unfortunate moment like: CPU1 - write at offset 1k CPU2 - read from offset 0 iomap_dio_rw(..., IOMAP_DIO_FORCE_WAIT); ext4_readpage(); ext4_handle_inode_extension() the read will zero out tail of the page as it still sees smaller inode size and thus page cache becomes inconsistent with on-disk contents with all the consequences. Fix the problem by moving inode size update into end_io handler which gets called before the page cache is invalidated. Reported-and-tested-by: Eric Whitney Fixes: 378f32bab371 ("ext4: introduce direct I/O write using iomap infrastructure") CC: stable@vger.kernel.org Signed-off-by: Jan Kara Acked-by: Dave Chinner Link: https://lore.kernel.org/r/20210415155417.4734-1-jack@suse.cz Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

iomap: pass a flags argument to iomap_dio_rw

2021-01-23T18:06:09Z

Pass a set of flags to iomap_dio_rw instead of the boolean wait_for_completion argument. The IOMAP_DIO_FORCE_WAIT flag replaces the wait_for_completion, but only needs to be passed when the iocb isn't synchronous to start with to simplify the callers. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Brian Foster [djwong: rework xfs_file.c so that we can push iomap changes separately] Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

ext4: don't leak old mountpoint samples

2020-12-22T18:08:46Z

When the first file is opened, ext4 samples the mountpoint of the filesystem in 64 bytes of the super block. It does so using strlcpy(), this means that the remaining bytes in the super block string buffer are untouched. If the mount point before had a longer path than the current one, it can be reconstructed. Consider the case where the fs was mounted to "/media/johnjdeveloper" and later to "/". The super block buffer then contains "/\x00edia/johnjdeveloper". This case was seen in the wild and caused confusion how the name of a developer ands up on the super block of a filesystem used in production... Fix this by using strncpy() instead of strlcpy(). The superblock field is defined to be a fixed-size char array, and it is already marked using __nonstring in fs/ext4/ext4.h. The consumer of the field in e2fsprogs already assumes that in the case of a 64+ byte mount path, that s_last_mounted will not be NUL terminated. Link: https://lore.kernel.org/r/X9ujIOJG/HqMr88R@mit.edu Reported-by: Richard Weinberger Signed-off-by: Theodore Ts'o Cc: stable@kernel.org

ext4: drop ext4_handle_dirty_super()

2020-12-22T18:08:46Z

The wrapper is now useless since it does what ext4_handle_dirty_metadata() does. Just remove it. Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20201216101844.22917-9-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: protect superblock modifications with a buffer lock

2020-12-22T18:08:46Z

Protect all superblock modifications (including checksum computation) with a superblock buffer lock. That way we are sure computed checksum matches current superblock contents (a mismatch could cause checksum failures in nojournal mode or if an unjournalled superblock update races with a journalled one). Also we avoid modifying superblock contents while it is being written out (which can cause DIF/DIX failures if we are running in nojournal mode). Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20201216101844.22917-4-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: make s_mount_flags modifications atomic

2020-11-07T04:01:05Z

Fast commit file system states are recorded in sbi->s_mount_flags. Fast commit expects these bit manipulations to be atomic. This patch adds helpers to make those modifications atomic. Suggested-by: Jan Kara Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20201106035911.1942128-21-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o

ext4: remove unnecessary fast commit calls from ext4_file_mmap

2020-11-07T04:01:05Z

Remove unnecessary calls to ext4_fc_start_update() and ext4_fc_stop_update() from ext4_file_mmap(). Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20201106035911.1942128-17-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o

ext4: main fast-commit commit path

2020-10-22T03:22:37Z

This patch adds main fast commit commit path handlers. The overall patch can be divided into two inter-related parts: (A) Metadata updates tracking This part consists of helper functions to track changes that need to be committed during a commit operation. These updates are maintained by Ext4 in different in-memory queues. Following are the APIs and their short description that are implemented in this patch: - ext4_fc_track_link/unlink/creat() - Track unlink. link and creat operations - ext4_fc_track_range() - Track changed logical block offsets inodes - ext4_fc_track_inode() - Track inodes - ext4_fc_mark_ineligible() - Mark file system fast commit ineligible() - ext4_fc_start_update() / ext4_fc_stop_update() / ext4_fc_start_ineligible() / ext4_fc_stop_ineligible() These functions are useful for co-ordinating inode updates with commits. (B) Main commit Path This part consists of functions to convert updates tracked in in-memory data structures into on-disk commits. Function ext4_fc_commit() is the main entry point to commit path. Reported-by: kernel test robot Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20201015203802.3597742-6-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o

ext4: flag as supporting buffered async reads

2020-10-18T14:36:12Z

ext4 uses generic_file_read_iter(), which already supports this. Cc: Theodore Ts'o Signed-off-by: Jens Axboe Link: https://lore.kernel.org/r/fb90cc2d-b12c-738f-21a4-dd7a8ae0556a@kernel.dk Signed-off-by: Theodore Ts'o

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2020-08-21T18:03:38Z

Pull ext4 updates from Ted Ts'o: "Improvements to ext4's block allocator performance for very large file systems, especially when the file system or files which are highly fragmented. There is a new mount option, prefetch_block_bitmaps which will pull in the block bitmaps and set up the in-memory buddy bitmaps when the file system is initially mounted. Beyond that, a lot of bug fixes and cleanups. In particular, a number of changes to make ext4 more robust in the face of write errors or file system corruptions" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (46 commits) ext4: limit the length of per-inode prealloc list ext4: reorganize if statement of ext4_mb_release_context() ext4: add mb_debug logging when there are lost chunks ext4: Fix comment typo "the the". jbd2: clean up checksum verification in do_one_pass() ext4: change to use fallthrough macro ext4: remove unused parameter of ext4_generic_delete_entry function mballoc: replace seq_printf with seq_puts ext4: optimize the implementation of ext4_mb_good_group() ext4: delete invalid comments near ext4_mb_check_limits() ext4: fix typos in ext4_mb_regular_allocator() comment ext4: fix checking of directory entry validity for inline directories fs: prevent BUG_ON in submit_bh_wbc() ext4: correctly restore system zone info when remount fails ext4: handle add_system_zone() failure in ext4_setup_system_zone() ext4: fold ext4_data_block_valid_rcu() into the caller ext4: check journal inode extents more carefully ext4: don't allow overlapping system zones ext4: handle error of ext4_setup_system_zone() on remount ext4: delete the invalid BUGON in ext4_mb_load_buddy_gfp() ...