kernel.git/fs/ext4/ioctl.c, branch linux-6.15.y

ext4: prevent stale extent cache entries caused by concurrent get es_cache

2025-06-27T10:13:18Z

[ Upstream commit f22a0ef2231a7d8374bb021eb86404d0e9de5a02 ] The EXT4_IOC_GET_ES_CACHE and EXT4_IOC_PRECACHE_EXTENTS currently invokes ext4_ext_precache() to preload the extent cache without holding the inode's i_rwsem. This can result in stale extent cache entries when competing with operations such as ext4_collapse_range() which calls ext4_ext_remove_space() or ext4_ext_shift_extents(). The problem arises when ext4_ext_remove_space() temporarily releases i_data_sem due to insufficient journal credits. During this interval, a concurrent EXT4_IOC_GET_ES_CACHE or EXT4_IOC_PRECACHE_EXTENTS may cache extent entries that are about to be deleted. As a result, these cached entries become stale and inconsistent with the actual extents. Loading the extents cache without holding the inode's i_rwsem or the mapping's invalidate_lock is not permitted besides during the writeback. Fix this by holding the i_rwsem during EXT4_IOC_GET_ES_CACHE and EXT4_IOC_PRECACHE_EXTENTS. Signed-off-by: Zhang Yi Link: https://patch.msgid.link/20250423085257.122685-6-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: remove redundant function ext4_has_metadata_csum

2025-03-17T15:19:41Z

Since commit f2b4fa19647e ("ext4: switch to using the crc32c library"), ext4_has_metadata_csum() is just an alias for ext4_has_feature_metadata_csum(). ext4_has_feature_metadata_csum() is generated by EXT4_FEATURE_RO_COMPAT_FUNCS and uses the regular naming convention for checking a single ext4 feature. Therefore, remove ext4_has_metadata_csum() and update all its callers to use ext4_has_feature_metadata_csum() directly. Signed-off-by: Eric Biggers Reviewed-by: Darrick J. Wong Link: https://patch.msgid.link/20250207031335.42637-1-ebiggers@kernel.org Signed-off-by: Theodore Ts'o

ext4: add more ext4_emergency_state() checks around sb_rdonly()

2025-03-13T14:16:34Z

Some functions check sb_rdonly() to make sure the file system isn't modified after it's read-only. Since we also don't want the file system modified if it's in an emergency state (shutdown or emergency_ro), we're adding additional ext4_emergency_state() checks where sb_rdonly() is checked. Suggested-by: Jan Kara Signed-off-by: Baokun Li Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Link: https://patch.msgid.link/20250122114130.229709-5-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o

fdget(), more trivial conversions

2024-11-03T06:28:06Z

all failure exits prior to fdget() leave the scope, all matching fdput() are immediately followed by leaving the scope. [xfs_ioc_commit_range() chunk moved here as well] Reviewed-by: Christian Brauner Signed-off-by: Al Viro

introduce fd_file(), convert all accessors to it.

2024-08-13T02:00:43Z

For any changes of struct fd representation we need to turn existing accesses to fields into calls of wrappers. Accesses to struct fd::flags are very few (3 in linux/file.h, 1 in net/socket.c, 3 in fs/overlayfs/file.c and 3 more in explicit initializers). Those can be dealt with in the commit converting to new layout; accesses to struct fd::file are too many for that. This commit converts (almost) all of f.file to fd_file(f). It's not entirely mechanical ('file' is used as a member name more than just in struct fd) and it does not even attempt to distinguish the uses in pointer context from those in boolean context; the latter will be eventually turned into a separate helper (fd_empty()). NOTE: mass conversion to fd_empty(), tempting as it might be, is a bad idea; better do that piecewise in commit that convert from fdget...() to CLASS(...). [conflicts in fs/fhandle.c, kernel/bpf/syscall.c, mm/memcontrol.c caught by git; fs/stat.c one got caught by git grep] [fs/xattr.c conflict] Reviewed-by: Christian Brauner Signed-off-by: Al Viro

ext4: use memtostr_pad() for s_volume_name

2024-07-05T17:14:51Z

As with the other strings in struct ext4_super_block, s_volume_name is not NUL terminated. The other strings were marked in commit 072ebb3bffe6 ("ext4: add nonstring annotations to ext4.h"). Using strscpy() isn't the right replacement for strncpy(); it should use memtostr_pad() instead. Reported-by: syzbot+50835f73143cc2905b9e@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/00000000000019f4c00619192c05@google.com/ Fixes: 744a56389f73 ("ext4: replace deprecated strncpy with alternatives") Signed-off-by: Kees Cook Link: https://patch.msgid.link/20240523225408.work.904-kees@kernel.org Signed-off-by: Theodore Ts'o

ext4: replace deprecated strncpy with alternatives

2024-05-03T03:55:10Z

strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. in file.c: s_last_mounted is marked as __nonstring meaning it does not need to be NUL-terminated. Let's instead use strtomem_pad() to copy bytes from the string source to the byte array destination -- while also ensuring to pad with zeroes. in ioctl.c: We can drop the memset and size argument in favor of using the new 2-argument version of strscpy_pad() -- which was introduced with Commit e6584c3964f2f ("string: Allow 2-argument strscpy()"). This guarantees NUL-termination and NUL-padding on the destination buffer -- which seems to be a requirement judging from this comment: | static int ext4_ioctl_getlabel(struct ext4_sb_info *sbi, char __user *user_label) | { | char label[EXT4_LABEL_MAX + 1]; | | /* | * EXT4_LABEL_MAX must always be smaller than FSLABEL_MAX because | * FSLABEL_MAX must include terminating null byte, while s_volume_name | * does not have to. | */ in super.c: s_first_error_func is marked as __nonstring meaning we can take the same approach as in file.c; just use strtomem_pad() Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20240321-strncpy-fs-ext4-file-c-v1-1-36a6a09fef0c@google.com Signed-off-by: Theodore Ts'o

ext4: remove unnecessary parameter "needed" in ext4_discard_preallocations

2024-01-18T15:52:45Z

The "needed" controls the number of ext4_prealloc_space to discard in ext4_discard_preallocations. Function ext4_discard_preallocations is supposed to discard all non-used preallocated blocks when "needed" is 0 and now ext4_discard_preallocations is always called with "needed" = 0. Remove unnecessary parameter "needed" and remove all non-used preallocated spaces in ext4_discard_preallocations to simplify the code. Note: If count of non-used preallocated spaces could be more than UINT_MAX, there was a memory leak as some non-used preallocated spaces are left ununsed and this commit will fix it. Otherwise, there is no behavior change. Signed-off-by: Kemeng Shi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20240105092102.496631-9-shikemeng@huaweicloud.com Signed-off-by: Theodore Ts'o

bdev: rename freeze and thaw helpers

2023-11-18T13:59:23Z

We have bdev_mark_dead() etc and we're going to move block device freezing to holder ops in the next patch. Make the naming consistent: * freeze_bdev() -> bdev_freeze() * thaw_bdev() -> bdev_thaw() Also document the return code. Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-2-599c19f4faac@kernel.org Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

ext4: convert to new timestamp accessors

2023-10-18T11:26:21Z

Convert to using the new inode timestamp accessor functions. Signed-off-by: Jeff Layton Link: https://lore.kernel.org/r/20231004185347.80880-33-jlayton@kernel.org Signed-off-by: Christian Brauner