kernel/linux.git/fs/ext4, branch v6.12.107

ext4: propagate errors from fast commit range replay

2026-08-27T12:32:05+00:00

commit d8b8dd3530bf41e14b118702cdaf9de64bb96885 upstream. ext4_fc_replay() stops replaying fast commit tags only when a tag handler returns a negative error. However, ext4_fc_replay_add_range() and ext4_fc_replay_del_range() currently return 0 from their common exit paths even after internal failures. This hides errors from ext4_fc_record_modified_inode(), ext4_map_blocks(), ext4_find_extent(), ext4_ext_insert_extent(), ext4_ext_replay_update_ex(), and ext4_ext_remove_space(). As a result, a failed ADD_RANGE or DEL_RANGE replay can be treated as successful and the replay code may continue with subsequent fast commit tags. This is particularly problematic for DEL_RANGE because it may already have marked blocks as free before ext4_ext_remove_space() fails. If the error is swallowed, replay may continue from a partially applied range operation. Return the saved error from the common exit paths and make the ERR_PTR() cases in ADD_RANGE store PTR_ERR() before jumping to out. Fixes: 8016e29f4362 ("ext4: fast commit recovery path") Cc: stable@vger.kernel.org Signed-off-by: Guanghui Yang <3497809730@qq.com> Reviewed-by: Jan Kara Link: https://patch.msgid.link/tencent_E3622146846A84C75C31C7D32AC4D5AD0605@qq.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: clear error before retrying inode xattr space fallback

2026-08-27T12:32:05+00:00

commit 409a7f12a0933ff2c617fa814c76cef0bd1d457a upstream. When ext4_xattr_make_inode_space() returns -ENOSPC, ext4_expand_extra_isize_ea() can retry the expansion with s_min_extra_isize. If that retry succeeds by finding enough ibody free space, control jumps directly to the shift label. The previous -ENOSPC is still stored in error in that path, so the function can update i_extra_isize but still return -ENOSPC to the caller. Clear error before retrying so a successful fallback expansion returns success. Reproduced with an ext4 image using 1 KiB blocks, project quota support, 256-byte inodes, and min_extra_isize/want_extra_isize set to 32. FS_IOC_FSSETXATTR failures dropped from 802 to 86 after the fix. Fixes: 69f3a3039b0d ("ext4: introduce ITAIL helper") Cc: stable@vger.kernel.org Signed-off-by: Guanghui Yang <3497809730@qq.com> Reviewed-by: Jan Kara Link: https://patch.msgid.link/tencent_192F8A699EFD21126E02101131C9546F3C08@qq.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: stop retrying saturated xattr cache entries

2026-08-27T12:32:05+00:00

commit 54b6bd40898de7906acb2bccc9a96d1b8e6b4323 upstream. ext4_xattr_block_set() retries when a cache entry selected for reuse has a saturated reference count after taking the buffer lock. The retry returns to the mbcache lookup without making that entry ineligible, so it can select the same unusable entry indefinitely. A task spinning there can hold the parent directory's i_rwsem and leave concurrent rmdir callers blocked. Normally a reusable entry has a reference count below EXT4_XATTR_REFCOUNT_MAX because the count and MBE_REUSABLE_B are updated under the same buffer lock. A corrupted filesystem can violate that invariant. The syzbot reproducer reports allocator and xattr corruption before triggering this retry loop. Check the untrusted on-disk count before incrementing it, avoiding overflow, and clear MBE_REUSABLE_B when it is already saturated. The next lookup then skips the entry that was just proven unusable. This mirrors the normal transition at EXT4_XATTR_REFCOUNT_MAX; the release path marks the entry reusable again on the exact 1024-to-1023 transition. Using the same QEMU harness and guest parameters, current unpatched Linux hung in 6 of 8 420-second trials with the do_rmdir signature; representative NMI backtraces caught the owner spinning in ext4_xattr_block_set(). The patched kernel completed 28 of 28 trials without a hung-task report; the final twelve trials exercised the reviewed overflow-safe form of the change. syzbot's patch testing also completed without reproducing the hang. Reported-and-tested-by: syzbot+e68dbebd9617a9250e8d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=e68dbebd9617a9250e8d Fixes: 65f8b80053a1 ("ext4: fix race when reusing xattr blocks") Cc: stable@vger.kernel.org Signed-off-by: Matthias Goergens Reviewed-by: Jan Kara Reported-by: syzbot+e68dbebd9617a9250e8d@syzkaller.appspotmail.com Tested-by: syzbot+e68dbebd9617a9250e8d@syzkaller.appspotmail.com Link: https://patch.msgid.link/20260802065941.1726052-1-matthias.goergens@gmail.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: fix fd leak in EXT4_IOC_MOVE_EXT cross-sb validation

2026-07-25T06:02:24+00:00

The backport of upstream commit c143957520c6 ("ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT") uses a bare 'return -EXDEV' which is safe upstream because the fd is managed via CLASS(fd) with automatic cleanup (commit 8152f8201088 ("fdget(), more trivial conversions")). However, on 6.12.y the ioctl still uses the traditional fdget/fdput pattern, so the bare return bypasses fdput(donor) at the mext_out label, leaking the file reference. Fix by setting err and using goto mext_out. Fixes: 74796e886ca3 ("ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT") Reported-by: Harshit Mogalapalli Signed-off-by: Yun Zhou Signed-off-by: Greg Kroah-Hartman

ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT

2026-07-24T14:10:58+00:00

[ Upstream commit c143957520c6c9b5cd72e0de8b52b814f0c576fe ] Reject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not belong to the same superblock as the original file. Currently, this validation is performed inside ext4_move_extents() by mext_check_validity(), but only after lock_two_nondirectories() has already acquired the inode locks. When the donor fd refers to a file on a different filesystem (e.g., overlayfs), this late validation creates a circular lock dependency: CPU0 (overlayfs write) CPU1 (ext4 ioctl) ---- ---- inode_lock(ovl_inode) mnt_want_write_file(filp) sb_start_write(ext4_sb) [sb_writers] backing_file_write_iter() vfs_iter_write(real_file) file_start_write(real_file) sb_start_write(ext4_sb) [blocked by freeze] lock_two_nondirectories() inode_lock(ovl_inode) [blocked] With a concurrent freeze operation holding sb_writers write side, this forms a deadlock cycle: CPU0 waits for freeze to complete, freeze waits for CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock. Since EXT4_IOC_MOVE_EXT exchanges physical extents between two files, it fundamentally requires both files to reside on the same ext4 filesystem. Moving the superblock check before any lock acquisition is both semantically correct and eliminates the circular dependency by ensuring that cross-filesystem donor fds are rejected before sb_writers or inode locks are taken. Fixes: fcf6b1b729bc ("ext4: refactor ext4_move_extents code base") Reported-by: syzbot+ad6118a7584b607c67f2@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ad6118a7584b607c67f2 Signed-off-by: Yun Zhou Reviewed-by: Jan Kara Reviewed-by: Andreas Dilger Link: https://patch.msgid.link/20260608152521.1292656-1-yun.zhou@windriver.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix kernel BUG in ext4_write_inline_data_end

2026-07-24T14:10:58+00:00

[ Upstream commit ad09aa45965d3fafaf9963bc78109b73c0f9ac8d ] When the data=journal mount option is used, the ext4_journalled_write_end() function incorrectly calls ext4_write_inline_data_end() without checking if the EXT4_STATE_MAY_INLINE_DATA flag is still set on the inode. If a previous attempt to convert the inline data to an extent failed (e.g. due to ENOSPC), the EXT4_STATE_MAY_INLINE_DATA flag is cleared, but the EXT4_INODE_INLINE_DATA flag remains set. In this scenario, the next call to ext4_write_begin() will not prepare the inline data xattr for writing, but ext4_journalled_write_end() will incorrectly attempt to write to it, triggering a BUG_ON(pos + len > EXT4_I(inode)->i_inline_size) in ext4_write_inline_data() since i_inline_size was not expanded. Fix this by ensuring that ext4_journalled_write_end() only calls ext4_write_inline_data_end() if the EXT4_STATE_MAY_INLINE_DATA flag is set, mirroring the behavior of ext4_write_end() and ext4_da_write_end(). Reported-by: syzbot+0c89d865531d053abb2d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0c89d865531d053abb2d Fixes: 3fdcfb668fd7 ("ext4: add journalled write support for inline data") Signed-off-by: Aditya Prakash Srivastava Reviewed-by: Jan Kara Link: https://patch.msgid.link/20260608065227.3018-1-aditya.ansh182@gmail.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix LOGFLUSH shutdown ordering to allow ordered-mode data writeback

2026-07-24T14:10:52+00:00

[ Upstream commit d99748ef1695ce17eaf51c64b7a06952fa7cddab ] In EXT4_GOING_FLAGS_LOGFLUSH mode, the EXT4_FLAGS_SHUTDOWN flag was set before calling ext4_force_commit(). This caused ordered-mode data writeback (triggered by journal commit) to fail with -EIO, since ext4_do_writepages() checks for the shutdown flag. The journal would then be aborted prematurely before the commit could succeed. Fix this by calling ext4_force_commit() first, then setting the shutdown flag, so that pending data can be written back correctly. Note that moving ext4_force_commit() before setting the shutdown flag creates a small window in which new writes may occur and generate new journal transactions. When the journal is subsequently aborted, the new transactions will not be able to write to disk. This is intentional because LOGFLUSH's semantics are to flush pre-existing journal entries before shutdown, not to guarantee atomicity for writes that race with the ioctl. Fixes: 783d94854499 ("ext4: add EXT4_IOC_GOINGDOWN ioctl") Signed-off-by: Zhang Yi Reviewed-by: Baokun Li Reviewed-by: Jan Kara Link: https://patch.msgid.link/20260424104201.1930823-1-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix possible null-ptr-deref in mbt_kunit_exit()

2026-05-23T11:04:41+00:00

[ Upstream commit 22f53f08d9eb837ce69b1a07641d414aac8d045f ] There's issue as follows: # test_new_blocks_simple: failed to initialize: -12 KASAN: null-ptr-deref in range [0x0000000000000638-0x000000000000063f] Tainted: [E]=UNSIGNED_MODULE, [N]=TEST RIP: 0010:mbt_kunit_exit+0x5e/0x3e0 [ext4_test] Call Trace: kunit_try_run_case_cleanup+0xbc/0x100 [kunit] kunit_generic_run_threadfn_adapter+0x89/0x100 [kunit] kthread+0x408/0x540 ret_from_fork+0xa76/0xdf0 ret_from_fork_asm+0x1a/0x30 If mbt_kunit_init() init testcase failed will lead to null-ptr-deref. So add test if 'sb' is inited success in mbt_kunit_exit(). Fixes: 7c9fa399a369 ("ext4: add first unit test for ext4_mb_new_blocks_simple in mballoc") Signed-off-by: Ye Bin Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Ojaswin Mujoo Link: https://patch.msgid.link/20260330133035.287842-6-yebin@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix missing brelse() in ext4_xattr_inode_dec_ref_all()

2026-05-07T04:09:39+00:00

commit 77d059519382bd66283e6a4e83ee186e87e7708f upstream. The commit c8e008b60492 ("ext4: ignore xattrs past end") introduced a refcount leak in when block_csum is false. ext4_xattr_inode_dec_ref_all() calls ext4_get_inode_loc() to get iloc.bh, but never releases it with brelse(). Fixes: c8e008b60492 ("ext4: ignore xattrs past end") Signed-off-by: Sohei Koyama Reviewed-by: Andreas Dilger Reviewed-by: Ritesh Harjani (IBM) Cc: stable@vger.kernel.org Reviewed-by: Zhang Yi Reviewed-by: Baokun Li Link: https://patch.msgid.link/20260406074830.8480-1-skoyama@ddn.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: fix bounds check in check_xattrs() to prevent out-of-bounds access

2026-05-07T04:09:39+00:00

commit eceafc31ea7b42c984ece10d79d505c0bb6615d5 upstream. The bounds check for the next xattr entry in check_xattrs() uses (void *)next >= end, which allows next to point within sizeof(u32) bytes of end. On the next loop iteration, IS_LAST_ENTRY() reads 4 bytes via *(__u32 *)(entry), which can overrun the valid xattr region. For example, if next lands at end - 1, the check passes since next < end, but IS_LAST_ENTRY() reads 4 bytes starting at end - 1, accessing 3 bytes beyond the valid region. Fix this by changing the check to (void *)next + sizeof(u32) > end, ensuring there is always enough space for the IS_LAST_ENTRY() read on the subsequent iteration. Fixes: 3478c83cf26b ("ext4: improve xattr consistency checking and error reporting") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20260224231429.31361-1-kartikey406@gmail.com/T/ [v1] Signed-off-by: Deepanshu Kartikey Link: https://patch.msgid.link/20260328150038.349497-1-kartikey406@gmail.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman