kernel/linux.git/fs/ext4/ext4.h, branch v6.19.11

ext4: introduce EXPORT_SYMBOL_FOR_EXT4_TEST() helper

2026-04-02T11:25:57+00:00

[ Upstream commit 49504a512587147dd6da3b4b08832ccc157b97dc ] Introduce EXPORT_SYMBOL_FOR_EXT4_TEST() helper for kuint test. Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://patch.msgid.link/20260314075258.1317579-2-yebin@huaweicloud.com Signed-off-by: Theodore Ts'o Stable-dep-of: 519b76ac0b31 ("ext4: fix mballoc-test.c is not compiled when EXT4_KUNIT_TESTS=M") Signed-off-by: Sasha Levin

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

2026-04-02T11:25:52+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: fast commit: make s_fc_lock reclaim-safe

2026-02-26T23:01:06+00:00

[ Upstream commit 491f2927ae097e2d405afe0b3fe841931ab8aad2 ] s_fc_lock can be acquired from inode eviction and thus is reclaim unsafe. Since the fast commit path holds s_fc_lock while writing the commit log, allocations under the lock can enter reclaim and invert the lock order with fs_reclaim. Add ext4_fc_lock()/ext4_fc_unlock() helpers which acquire s_fc_lock under memalloc_nofs_save()/restore() context and use them everywhere so allocations under the lock cannot recurse into filesystem reclaim. Fixes: 6593714d67ba ("ext4: hold s_fc_lock while during fast commit") Signed-off-by: Li Chen Reviewed-by: Baokun Li Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Link: https://patch.msgid.link/20260106120621.440126-1-me@linux.beauty Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: add checks for large folio incompatibilities when BS > PS

2025-11-29T03:35:28+00:00

Supporting a block size greater than the page size (BS > PS) requires support for large folios. However, several features (e.g., encrypt) do not yet support large folios. To prevent conflicts, this patch adds checks at mount time to prohibit these features from being used when BS > PS. Since these features cannot be changed on remount, there is no need to check on remount. This patch adds s_max_folio_order, initialized during mount according to filesystem features and mount options. If s_max_folio_order is 0, large folios are disabled. With this in place, ext4_set_inode_mapping_order() can be simplified by checking s_max_folio_order, avoiding redundant checks. Signed-off-by: Baokun Li Reviewed-by: Jan Kara Reviewed-by: Zhang Yi Reviewed-by: Ojaswin Mujoo Message-ID: <20251121090654.631996-24-libaokun@huaweicloud.com> Signed-off-by: Theodore Ts'o

ext4: add EXT4_LBLK_TO_PG and EXT4_PG_TO_LBLK for block/page conversion

2025-11-29T03:35:27+00:00

As BS > PS support is coming, all block number to page index (and vice-versa) conversions must now go via bytes. Added EXT4_LBLK_TO_PG() and EXT4_PG_TO_LBLK() macros to simplify these conversions and handle both BS <= PS and BS > PS scenarios cleanly. Suggested-by: Jan Kara Signed-off-by: Baokun Li Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Message-ID: <20251121090654.631996-11-libaokun@huaweicloud.com> Signed-off-by: Theodore Ts'o

ext4: add EXT4_LBLK_TO_B macro for logical block to bytes conversion

2025-11-29T03:35:27+00:00

No functional changes. Signed-off-by: Baokun Li Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Message-ID: <20251121090654.631996-10-libaokun@huaweicloud.com> Signed-off-by: Theodore Ts'o

ext4: introduce s_min_folio_order for future BS > PS support

2025-11-29T03:35:26+00:00

This commit introduces the s_min_folio_order field to the ext4_sb_info structure. This field will store the minimum folio order required by the current filesystem, laying groundwork for future support of block sizes greater than PAGE_SIZE. Signed-off-by: Baokun Li Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Reviewed-by: Pankaj Raghav Reviewed-by: Ojaswin Mujoo Message-ID: <20251121090654.631996-7-libaokun@huaweicloud.com> Signed-off-by: Theodore Ts'o

ext4: remove PAGE_SIZE checks for rec_len conversion

2025-11-29T03:35:26+00:00

Previously, ext4_rec_len_(to|from)_disk only performed complex rec_len conversions when PAGE_SIZE >= 65536 to reduce complexity. However, we are soon to support file system block sizes greater than page size, which makes these conditional checks unnecessary. Thus, these checks are now removed. Signed-off-by: Baokun Li Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Message-ID: <20251121090654.631996-4-libaokun@huaweicloud.com> Signed-off-by: Theodore Ts'o

ext4: rename EXT4_GET_BLOCKS_PRE_IO

2025-11-26T22:13:33+00:00

This flag has been generalized to split an unwritten extent when we do dio or dioread_nolock writeback, or to avoid merge new extents which was created by extents split. Update some related comments too. Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Reviewed-by: Baokun Li Signed-off-by: Yang Erkun Message-ID: <20251112084538.1658232-2-yangerkun@huawei.com> Signed-off-by: Theodore Ts'o

ext4: pass out extent seq counter when mapping blocks

2025-11-06T15:44:39+00:00

When creating or querying mapping blocks using the ext4_map_blocks() and ext4_map_{query|create}_blocks() helpers, also pass out the extent sequence number of the block mapping info through the ext4_map_blocks structure. This sequence number can later serve as a valid cookie within iomap infrastructure and the move extents procedure. Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Message-ID: <20251013015128.499308-5-yi.zhang@huaweicloud.com> Signed-off-by: Theodore Ts'o