kernel/linux.git/fs/ext4/migrate.c, branch v6.6.132

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: fix i_data_sem unlock order in ext4_ind_migrate()

2024-10-10T09:57:39+00:00

[ Upstream commit cc749e61c011c255d81b192a822db650c68b313f ] Fuzzing reports a possible deadlock in jbd2_log_wait_commit. This issue is triggered when an EXT4_IOC_MIGRATE ioctl is set to require synchronous updates because the file descriptor is opened with O_SYNC. This can lead to the jbd2_journal_stop() function calling jbd2_might_wait_for_commit(), potentially causing a deadlock if the EXT4_IOC_MIGRATE call races with a write(2) system call. This problem only arises when CONFIG_PROVE_LOCKING is enabled. In this case, the jbd2_might_wait_for_commit macro locks jbd2_handle in the jbd2_journal_stop function while i_data_sem is locked. This triggers lockdep because the jbd2_journal_start function might also lock the same jbd2_handle simultaneously. Found by Linux Verification Center (linuxtesting.org) with syzkaller. Reviewed-by: Ritesh Harjani (IBM) Co-developed-by: Mikhail Ukhin Signed-off-by: Mikhail Ukhin Signed-off-by: Artem Sadovnikov Rule: add Link: https://lore.kernel.org/stable/20240404095000.5872-1-mish.uxin2012%40yandex.ru Link: https://patch.msgid.link/20240829152210.2754-1-ancowi69@gmail.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: avoid deadlock in fs reclaim with page writeback

2023-05-13T22:05:04+00:00

Ext4 has a filesystem wide lock protecting ext4_writepages() calls to avoid races with switching of journalled data flag or inode format. This lock can however cause a deadlock like: CPU0 CPU1 ext4_writepages() percpu_down_read(sbi->s_writepages_rwsem); ext4_change_inode_journal_flag() percpu_down_write(sbi->s_writepages_rwsem); - blocks, all readers block from now on ext4_do_writepages() ext4_init_io_end() kmem_cache_zalloc(io_end_cachep, GFP_KERNEL) fs_reclaim frees dentry... dentry_unlink_inode() iput() - last ref => iput_final() - inode dirty => write_inode_now()... ext4_writepages() tries to acquire sbi->s_writepages_rwsem and blocks forever Make sure we cannot recurse into filesystem reclaim from writeback code to avoid the deadlock. Reported-by: syzbot+6898da502aef574c5f8a@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/0000000000004c66b405fa108e27@google.com Fixes: c8585c6fcaf2 ("ext4: fix races between changing inode journal mode and ext4_writepages") CC: stable@vger.kernel.org Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20230504124723.20205-1-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: fix warning in 'ext4_da_release_space'

2022-11-06T05:07:59+00:00

Syzkaller report issue as follows: EXT4-fs (loop0): Free/Dirty block details EXT4-fs (loop0): free_blocks=0 EXT4-fs (loop0): dirty_blocks=0 EXT4-fs (loop0): Block reservation details EXT4-fs (loop0): i_reserved_data_blocks=0 EXT4-fs warning (device loop0): ext4_da_release_space:1527: ext4_da_release_space: ino 18, to_free 1 with only 0 reserved data blocks ------------[ cut here ]------------ WARNING: CPU: 0 PID: 92 at fs/ext4/inode.c:1528 ext4_da_release_space+0x25e/0x370 fs/ext4/inode.c:1524 Modules linked in: CPU: 0 PID: 92 Comm: kworker/u4:4 Not tainted 6.0.0-syzkaller-09423-g493ffd6605b2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:ext4_da_release_space+0x25e/0x370 fs/ext4/inode.c:1528 RSP: 0018:ffffc900015f6c90 EFLAGS: 00010296 RAX: 42215896cd52ea00 RBX: 0000000000000000 RCX: 42215896cd52ea00 RDX: 0000000000000000 RSI: 0000000080000001 RDI: 0000000000000000 RBP: 1ffff1100e907d96 R08: ffffffff816aa79d R09: fffff520002bece5 R10: fffff520002bece5 R11: 1ffff920002bece4 R12: ffff888021fd2000 R13: ffff88807483ecb0 R14: 0000000000000001 R15: ffff88807483e740 FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555569ba628 CR3: 000000000c88e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ext4_es_remove_extent+0x1ab/0x260 fs/ext4/extents_status.c:1461 mpage_release_unused_pages+0x24d/0xef0 fs/ext4/inode.c:1589 ext4_writepages+0x12eb/0x3be0 fs/ext4/inode.c:2852 do_writepages+0x3c3/0x680 mm/page-writeback.c:2469 __writeback_single_inode+0xd1/0x670 fs/fs-writeback.c:1587 writeback_sb_inodes+0xb3b/0x18f0 fs/fs-writeback.c:1870 wb_writeback+0x41f/0x7b0 fs/fs-writeback.c:2044 wb_do_writeback fs/fs-writeback.c:2187 [inline] wb_workfn+0x3cb/0xef0 fs/fs-writeback.c:2227 process_one_work+0x877/0xdb0 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 Above issue may happens as follows: ext4_da_write_begin ext4_create_inline_data ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS); ext4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA); __ext4_ioctl ext4_ext_migrate -> will lead to eh->eh_entries not zero, and set extent flag ext4_da_write_begin ext4_da_convert_inline_data_to_extent ext4_da_write_inline_data_begin ext4_da_map_blocks ext4_insert_delayed_block if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) if (!ext4_es_scan_clu(inode, &ext4_es_is_mapped, lblk)) ext4_clu_mapped(inode, EXT4_B2C(sbi, lblk)); -> will return 1 allocated = true; ext4_es_insert_delayed_block(inode, lblk, allocated); ext4_writepages mpage_map_and_submit_extent(handle, &mpd, &give_up_on_write); -> return -ENOSPC mpage_release_unused_pages(&mpd, give_up_on_write); -> give_up_on_write == 1 ext4_es_remove_extent ext4_da_release_space(inode, reserved); if (unlikely(to_free > ei->i_reserved_data_blocks)) -> to_free == 1 but ei->i_reserved_data_blocks == 0 -> then trigger warning as above To solve above issue, forbid inode do migrate which has inline data. Cc: stable@kernel.org Reported-by: syzbot+c740bb18df70ad00952e@syzkaller.appspotmail.com Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20221018022701.683489-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o

ext4: factor out ext4_free_ext_path()

2022-10-01T03:46:54+00:00

Factor out ext4_free_ext_path() to free extent path. As after previous patch 'ext4_ext_drop_refs()' is only used in 'extents.c', so make it static. Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220924021211.3831551-3-yebin10@huawei.com Signed-off-by: Theodore Ts'o

ext4: recover csum seed of tmp_inode after migrating to extents

2022-08-03T03:56:02+00:00

When migrating to extents, the checksum seed of temporary inode need to be replaced by inode's, otherwise the inode checksums will be incorrect when swapping the inodes data. However, the temporary inode can not match it's checksum to itself since it has lost it's own checksum seed. mkfs.ext4 -F /dev/sdc mount /dev/sdc /mnt/sdc xfs_io -fc "pwrite 4k 4k" -c "fsync" /mnt/sdc/testfile chattr -e /mnt/sdc/testfile chattr +e /mnt/sdc/testfile umount /dev/sdc fsck -fn /dev/sdc ======== ... Pass 1: Checking inodes, blocks, and sizes Inode 13 passes checks, but checksum does not match inode. Fix? no ... ======== The fix is simple, save the checksum seed of temporary inode, and recover it after migrating to extents. Fixes: e81c9302a6c3 ("ext4: set csum seed in tmp inode while migrating to extents") Signed-off-by: Li Lingfeng Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220617062515.2113438-1-lilingfeng3@huawei.com Signed-off-by: Theodore Ts'o

ext4: fix a doubled word "need" in a comment

2022-06-18T23:36:20+00:00

Signed-off-by: Xiang wangx Link: https://lore.kernel.org/r/20220605091503.12513-1-wangxiang@cdjrlc.com Signed-off-by: Theodore Ts'o

fs/ext4: fix comments mentioning i_mutex

2022-02-03T15:57:53+00:00

inode->i_mutex has been replaced with inode->i_rwsem long ago. Fix comments still mentioning i_mutex. Signed-off-by: hongnanli Link: https://lore.kernel.org/r/20220121070611.21618-1-hongnan.li@linux.alibaba.com Signed-off-by: Theodore Ts'o

ext4: don't use the orphan list when migrating an inode

2022-01-10T18:25:56+00:00

We probably want to remove the indirect block to extents migration feature after a deprecation window, but until then, let's fix a potential data loss problem caused by the fact that we put the tmp_inode on the orphan list. In the unlikely case where we crash and do a journal recovery, the data blocks belonging to the inode being migrated are also represented in the tmp_inode on the orphan list --- and so its data blocks will get marked unallocated, and available for reuse. Instead, stop putting the tmp_inode on the oprhan list. So in the case where we crash while migrating the inode, we'll leak an inode, which is not a disaster. It will be easily fixed the next time we run fsck, and it's better than potentially having blocks getting claimed by two different files, and losing data as a result. Signed-off-by: Theodore Ts'o Reviewed-by: Lukas Czerner Cc: stable@kernel.org

ext4: set csum seed in tmp inode while migrating to extents

2022-01-10T18:25:56+00:00

When migrating to extents, the temporary inode will have it's own checksum seed. This means that, when swapping the inodes data, the inode checksums will be incorrect. This can be fixed by recalculating the extents checksums again. Or simply by copying the seed into the temporary inode. Link: https://bugzilla.kernel.org/show_bug.cgi?id=213357 Reported-by: Jeroen van Wolffelaar Signed-off-by: Luís Henriques Link: https://lore.kernel.org/r/20211214175058.19511-1-lhenriques@suse.de Signed-off-by: Theodore Ts'o Cc: stable@kernel.org