kernel/linux.git/fs/ext4/ext4.h, branch v6.6.131

ext4: fix use-after-free in update_super_work when racing with umount

2026-04-02T11:07:28+00:00

commit d15e4b0a418537aafa56b2cb80d44add83e83697 upstream. Commit b98535d09179 ("ext4: fix bug_on in start_this_handle during umount filesystem") moved ext4_unregister_sysfs() before flushing s_sb_upd_work to prevent new error work from being queued via /proc/fs/ext4/xx/mb_groups reads during unmount. However, this introduced a use-after-free because update_super_work calls ext4_notify_error_sysfs() -> sysfs_notify() which accesses the kobject's kernfs_node after it has been freed by kobject_del() in ext4_unregister_sysfs(): update_super_work ext4_put_super ----------------- -------------- ext4_unregister_sysfs(sb) kobject_del(&sbi->s_kobj) __kobject_del() sysfs_remove_dir() kobj->sd = NULL sysfs_put(sd) kernfs_put() // RCU free ext4_notify_error_sysfs(sbi) sysfs_notify(&sbi->s_kobj) kn = kobj->sd // stale pointer kernfs_get(kn) // UAF on freed kernfs_node ext4_journal_destroy() flush_work(&sbi->s_sb_upd_work) Instead of reordering the teardown sequence, fix this by making ext4_notify_error_sysfs() detect that sysfs has already been torn down by checking s_kobj.state_in_sysfs, and skipping the sysfs_notify() call in that case. A dedicated mutex (s_error_notify_mutex) serializes ext4_notify_error_sysfs() against kobject_del() in ext4_unregister_sysfs() to prevent TOCTOU races where the kobject could be deleted between the state_in_sysfs check and the sysfs_notify() call. Fixes: b98535d09179 ("ext4: fix bug_on in start_this_handle during umount filesystem") Cc: Jiayuan Chen Suggested-by: Jan Kara Signed-off-by: Jiayuan Chen Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Jan Kara Link: https://patch.msgid.link/20260319120336.157873-1-jiayuan.chen@linux.dev Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: get rid of ppath in ext4_ext_insert_extent()

2026-03-25T10:05:32+00:00

[ Upstream commit f7d1331f16a869c76a5102caebb58e840e1d509c ] The use of path and ppath is now very confusing, so to make the code more readable, pass path between functions uniformly, and get rid of ppath. To get rid of the ppath in ext4_ext_insert_extent(), the following is done here: * Free the extents path when an error is encountered. * Its caller needs to update ppath if it uses ppath. * Free path when npath is used, free npath when it is not used. * The got_allocated_blocks label in ext4_ext_map_blocks() does not update err now, so err is updated to 0 if the err returned by ext4_ext_search_right() is greater than 0 and is about to enter got_allocated_blocks. No functional changes. Signed-off-by: Baokun Li Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Tested-by: Ojaswin Mujoo Link: https://patch.msgid.link/20240822023545.1994557-15-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Stable-dep-of: 22784ca541c0 ("ext4: subdivide EXT4_EXT_DATA_VALID1") Signed-off-by: Sasha Levin

ext4: get rid of ppath in ext4_find_extent()

2026-03-25T10:05:32+00:00

[ Upstream commit 0be4c0c2f17bd10ae16c852f02d51a6a7b318aca ] The use of path and ppath is now very confusing, so to make the code more readable, pass path between functions uniformly, and get rid of ppath. Getting rid of ppath in ext4_find_extent() requires its caller to update ppath. These ppaths will also be dropped later. No functional changes. Signed-off-by: Baokun Li Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Tested-by: Ojaswin Mujoo Link: https://patch.msgid.link/20240822023545.1994557-12-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Stable-dep-of: 22784ca541c0 ("ext4: subdivide EXT4_EXT_DATA_VALID1") Signed-off-by: Sasha Levin

ext4: fix error message when rejecting the default hash

2026-01-11T14:22:33+00:00

commit a2187431c395cdfbf144e3536f25468c64fc7cfa upstream. Commit 985b67cd8639 ("ext4: filesystems without casefold feature cannot be mounted with siphash") properly rejects volumes where s_def_hash_version is set to DX_HASH_SIPHASH, but the check and the error message should not look into casefold setup - a filesystem should never have DX_HASH_SIPHASH as the default hash. Fix it and, since we are there, move the check to ext4_hash_info_init. Fixes:985b67cd8639 ("ext4: filesystems without casefold feature cannot be mounted with siphash") Signed-off-by: Gabriel Krisman Bertazi Link: https://patch.msgid.link/87jzg1en6j.fsf_-_@mailhost.krisman.be Signed-off-by: Theodore Ts'o Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

ext4: fix checks for orphan inodes

2025-10-15T09:58:08+00:00

commit acf943e9768ec9d9be80982ca0ebc4bfd6b7631e upstream. When orphan file feature is enabled, inode can be tracked as orphan either in the standard orphan list or in the orphan file. The first can be tested by checking ei->i_orphan list head, the second is recorded by EXT4_STATE_ORPHAN_FILE inode state flag. There are several places where we want to check whether inode is tracked as orphan and only some of them properly check for both possibilities. Luckily the consequences are mostly minor, the worst that can happen is that we track an inode as orphan although we don't need to and e2fsck then complains (resulting in occasional ext4/307 xfstest failures). Fix the problem by introducing a helper for checking whether an inode is tracked as orphan and use it in appropriate places. Fixes: 4a79a98c7b19 ("ext4: Improve scalability of ext4 orphan file handling") Cc: stable@kernel.org Signed-off-by: Jan Kara Reviewed-by: Zhang Yi Message-ID: <20250925123038.20264-2-jack@suse.cz> Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: factor out ext4_get_maxbytes()

2025-06-27T10:08:47+00:00

commit dbe27f06fa38b9bfc598f8864ae1c5d5831d9992 upstream. There are several locations that get the correct maxbytes value based on the inode's block type. It would be beneficial to extract a common helper function to make the code more clear. Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Reviewed-by: Baokun Li Link: https://patch.msgid.link/20250506012009.3896990-3-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: remove writable userspace mappings before truncating page cache

2025-06-04T12:42:12+00:00

[ Upstream commit 17207d0bb209e8b40f27d7f3f96e82a78af0bf2c ] When zeroing a range of folios on the filesystem which block size is less than the page size, the file's mapped blocks within one page will be marked as unwritten, we should remove writable userspace mappings to ensure that ext4_page_mkwrite() can be called during subsequent write access to these partial folios. Otherwise, data written by subsequent mmap writes may not be saved to disk. $mkfs.ext4 -b 1024 /dev/vdb $mount /dev/vdb /mnt $xfs_io -t -f -c "pwrite -S 0x58 0 4096" -c "mmap -rw 0 4096" \ -c "mwrite -S 0x5a 2048 2048" -c "fzero 2048 2048" \ -c "mwrite -S 0x59 2048 2048" -c "close" /mnt/foo $od -Ax -t x1z /mnt/foo 000000 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 * 000800 59 59 59 59 59 59 59 59 59 59 59 59 59 59 59 59 * 001000 $umount /mnt && mount /dev/vdb /mnt $od -Ax -t x1z /mnt/foo 000000 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 * 000800 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 001000 Fix this by introducing ext4_truncate_page_cache_block_range() to remove writable userspace mappings when truncating a partial folio range. Additionally, move the journal data mode-specific handlers and truncate_pagecache_range() into this function, allowing it to serve as a common helper that correctly manages the page cache in preparation for block range manipulations. Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Link: https://patch.msgid.link/20241220011637.1157197-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: do not convert the unwritten extents if data writeback fails

2025-06-04T12:41:59+00:00

[ Upstream commit e856f93e0fb249955f7d5efb18fe20500a9ccc6d ] When dioread_nolock is turned on (the default), it will convert unwritten extents to written at ext4_end_io_end(), even if the data writeback fails. It leads to the possibility that stale data may be exposed when the physical block corresponding to the file data is read-only (i.e., writes return -EIO, but reads are normal). Therefore a new ext4_io_end->flags EXT4_IO_END_FAILED is added, which indicates that some bio write-back failed in the current ext4_io_end. When this flag is set, the unwritten to written conversion is no longer performed. Users can read the data normally until the caches are dropped, after that, the failed extents can only be read to all 0. Signed-off-by: Baokun Li Reviewed-by: Jan Kara Reviewed-by: Zhang Yi Link: https://patch.msgid.link/20250122110533.4116662-3-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: convert to new timestamp accessors

2025-01-09T12:31:40+00:00

[ Upstream commit b898ab233611f7903d88c0b10f8145e1c15d3642 ] 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 Stable-dep-of: c7fc0366c656 ("ext4: partial zero eof block on unaligned inode size extension") Signed-off-by: Sasha Levin

ext4: fix race in buffer_head read fault injection

2024-12-09T09:31:46+00:00

[ Upstream commit 2f3d93e210b9c2866c8b3662adae427d5bf511ec ] When I enabled ext4 debug for fault injection testing, I encountered the following warning: EXT4-fs error (device sda): ext4_read_inode_bitmap:201: comm fsstress: Cannot read inode bitmap - block_group = 8, inode_bitmap = 1051 WARNING: CPU: 0 PID: 511 at fs/buffer.c:1181 mark_buffer_dirty+0x1b3/0x1d0 The root cause of the issue lies in the improper implementation of ext4's buffer_head read fault injection. The actual completion of buffer_head read and the buffer_head fault injection are not atomic, which can lead to the uptodate flag being cleared on normally used buffer_heads in race conditions. [CPU0] [CPU1] [CPU2] ext4_read_inode_bitmap ext4_read_bh() ext4_read_inode_bitmap if (buffer_uptodate(bh)) return bh jbd2_journal_commit_transaction __jbd2_journal_refile_buffer __jbd2_journal_unfile_buffer __jbd2_journal_temp_unlink_buffer ext4_simulate_fail_bh() clear_buffer_uptodate mark_buffer_dirty WARN_ON_ONCE(!buffer_uptodate(bh)) The best approach would be to perform fault injection in the IO completion callback function, rather than after IO completion. However, the IO completion callback function cannot get the fault injection code in sb. Fix it by passing the result of fault injection into the bh read function, we simulate faults within the bh read function itself. This requires adding an extra parameter to the bh read functions that need fault injection. Fixes: 46f870d690fe ("ext4: simulate various I/O and checksum errors when reading metadata") Signed-off-by: Long Li Link: https://patch.msgid.link/20240906091746.510163-1-leo.lilong@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin