ext4: clear EXT4_STATE_MAY_INLINE_DATA in swap_inode_boot_loader()

PATCH In review Hui Peng 3 participants 3 messages Sep 19 – Sep 24 ext4 file system

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Hui Peng

author

2026-09-19 20:48 UTC #0 lore raw

PATCH 1/1 ext4: clear EXT4_STATE_MAY_INLINE_DATA in swap_inode_boot_loader()

swap_inode_boot_loader() (EXT4_IOC_SWAP_BOOT) checks !ext4_has_inline_data(inode), but neither checks ext4_has_inline_data(inode_bl) nor clears EXT4_STATE_MAY_INLINE_DATA on inode and inode_bl after swapping their inode data.

When a newly created empty file (which has EXT4_STATE_MAY_INLINE_DATA set in memory) is swapped with a non-empty EXT4_BOOT_LOADER_INO that already has extent blocks, the target inode retains EXT4_STATE_MAY_INLINE_DATA == 1 alongside extent blocks. A subsequent ftruncate() + small pwrite() + fsync() dirties folio 0 while converting the inode to inline data, hitting BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) in ext4_writepages().

Reject inline data on inode_bl and clear EXT4_STATE_MAY_INLINE_DATA on both inodes in swap_inode_boot_loader().

Fixes 67a11611e1a5 ("ext4: fix check of inode in swap_inode_boot_loader")

Assisted-by LLM

Signed-off-by Hui Peng <[email protected]>

---

fs/ext4/ioctl.c +3 -1

@@ -397,7 +397,7 @@ static long swap_inode_boot_loader(struct super_block *sb,
 	if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode) ||
 	    IS_SWAPFILE(inode) || IS_ENCRYPTED(inode) ||
 	    (EXT4_I(inode)->i_flags & EXT4_JOURNAL_DATA_FL) ||
-	    ext4_has_inline_data(inode)) {
+	    ext4_has_inline_data(inode) || ext4_has_inline_data(inode_bl)) {
 		err = -EINVAL;
 		goto journal_err_out;
 	}

@@ -461,6 +461,8 @@ static long swap_inode_boot_loader(struct super_block *sb,
 	size_bl = (qsize_t)(inode_bl->i_blocks) * (1 << 9) + inode_bl->i_bytes;
 	diff = size - size_bl;
 	swap_inode_data(inode, inode_bl);
+	ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+	ext4_clear_inode_state(inode_bl, EXT4_STATE_MAY_INLINE_DATA);
 
 	inode_set_ctime_current(inode);
 	inode_set_ctime_current(inode_bl);

Signature · 1 line

2.43.0

[email protected]

AI review

2026-09-19 21:00 UTC #1 lore raw

Sashiko has reviewed this patch and found no issues. It looks great!

Quoted 14 lines

swap_inode_boot_loader() (EXT4_IOC_SWAP_BOOT) checks !ext4_has_inline_data(inode), but neither checks ext4_has_inline_data(inode_bl) nor clears EXT4_STATE_MAY_INLINE_DATA on inode and inode_bl after swapping their inode data.
When a newly created empty file (which has EXT4_STATE_MAY_INLINE_DATA set in memory) is swapped with a non-empty EXT4_BOOT_LOADER_INO that already has extent blocks, the target inode retains EXT4_STATE_MAY_INLINE_DATA == 1 alongside extent blocks. A subsequent ftruncate() + small pwrite() + fsync() dirties folio 0 while converting the inode to inline data, hitting BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) in ext4_writepages().

Quoted 6 lines

Reject inline data on inode_bl and clear EXT4_STATE_MAY_INLINE_DATA on both inodes in swap_inode_boot_loader().
Fixes 67a11611e1a5 ("ext4: fix check of inode in swap_inode_boot_loader")
Assisted-by LLM
Signed-off-by Hui Peng <[email protected]>

Sashiko has reviewed this patch and found no issues. It looks great!

Signature · 1 line

Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=1

Jan Kara

reviewer

2026-09-24 16:02 UTC #2 lore raw

In reply to Hui Peng

Quoted 25 lines · Hui Peng

swap_inode_boot_loader() (EXT4_IOC_SWAP_BOOT) checks !ext4_has_inline_data(inode), but neither checks ext4_has_inline_data(inode_bl) nor clears EXT4_STATE_MAY_INLINE_DATA on inode and inode_bl after swapping their inode data.
When a newly created empty file (which has EXT4_STATE_MAY_INLINE_DATA set in memory) is swapped with a non-empty EXT4_BOOT_LOADER_INO that already has extent blocks, the target inode retains EXT4_STATE_MAY_INLINE_DATA == 1 alongside extent blocks. A subsequent ftruncate() + small pwrite() + fsync() dirties folio 0 while converting the inode to inline data, hitting BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) in ext4_writepages().
Reject inline data on inode_bl and clear EXT4_STATE_MAY_INLINE_DATA on both inodes in swap_inode_boot_loader().
Fixes 67a11611e1a5 ("ext4: fix check of inode in swap_inode_boot_loader")
Assisted-by LLM
Signed-off-by Hui Peng <[email protected]>
---

fs/ext4/ioctl.c static long swap_inode_boot_loader(struct super_block *sb, · line 403

Quoted 8 lines

fs/ext4/ioctl.c +1 -1

@@ -397,7 +397,7 @@ static long swap_inode_boot_loader(struct super_block *sb,
 	if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode) ||
 	    IS_SWAPFILE(inode) || IS_ENCRYPTED(inode) ||
 	    (EXT4_I(inode)->i_flags & EXT4_JOURNAL_DATA_FL) ||
-	    ext4_has_inline_data(inode)) {
+	    ext4_has_inline_data(inode) || ext4_has_inline_data(inode_bl)) {
 		err = -EINVAL;
 		goto journal_err_out;
 	}

I guess instead we should add a check to check_igot_inode() that inode doesn't have inline data if EXT4_IGET_SPECIAL flag is set.

fs/ext4/ioctl.c static long swap_inode_boot_loader(struct super_block *sb, · line 465

Quoted 6 lines

fs/ext4/ioctl.c +2 -0

@@ -461,6 +461,8 @@ static long swap_inode_boot_loader(struct super_block *sb,
 	size_bl = (qsize_t)(inode_bl->i_blocks) * (1 << 9) + inode_bl->i_bytes;
 	diff = size - size_bl;
 	swap_inode_data(inode, inode_bl);
+	ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+	ext4_clear_inode_state(inode_bl, EXT4_STATE_MAY_INLINE_DATA);

Please don't touch inode_bl. That one should never have EXT4_STATE_MAY_INLINE_DATA set (and nobody can manipulate it directly anyway). For 'inode' I agree it will get blocks from inode_bl so better just clear EXT4_STATE_MAY_INLINE_DATA.

Honza

Signature · 2 lines

Jan Kara <[email protected]>
SUSE Labs, CR