[PATCH 6.1 044/481] ext4: subdivide EXT4_EXT_DATA_VALID1

Greg Kroah-Hartman
2026-03-23T16:11:18Z

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Zhang Yi <yi.zhang@huawei.com>

[ Upstream commit 22784ca541c0f01c5ebad14e8228298dc0a390ed ]

When splitting an extent, if the EXT4_GET_BLOCKS_CONVERT flag is set and
it is necessary to split the target extent in the middle,
ext4_split_extent() first handles splitting the latter half of the
extent and passes the EXT4_EXT_DATA_VALID1 flag. This flag implies that
all blocks before the split point contain valid data; however, this
assumption is incorrect.

Therefore, subdivid EXT4_EXT_DATA_VALID1 into
EXT4_EXT_DATA_ENTIRE_VALID1 and EXT4_EXT_DATA_PARTIAL_VALID1, which
indicate that the first half of the extent is either entirely valid or
only partially valid, respectively. These two flags cannot be set
simultaneously.

This patch does not use EXT4_EXT_DATA_PARTIAL_VALID1, it only replaces
EXT4_EXT_DATA_VALID1 with EXT4_EXT_DATA_ENTIRE_VALID1 at the location
where it is set, no logical changes.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Cc: stable@kernel.org
Message-ID: <20251129103247.686136-2-yi.zhang@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ext4/extents.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 6da0bf3cf406d..e2f9c27c7e161 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -43,8 +43,13 @@
#define EXT4_EXT_MARK_UNWRIT1 0x2 /* mark first half unwritten */
#define EXT4_EXT_MARK_UNWRIT2 0x4 /* mark second half unwritten */

-#define EXT4_EXT_DATA_VALID1 0x8 /* first half contains valid data */
-#define EXT4_EXT_DATA_VALID2 0x10 /* second half contains valid data */
+/* first half contains valid data */
+#define EXT4_EXT_DATA_ENTIRE_VALID1 0x8 /* has entirely valid data */
+#define EXT4_EXT_DATA_PARTIAL_VALID1 0x10 /* has partially valid data */
+#define EXT4_EXT_DATA_VALID1 (EXT4_EXT_DATA_ENTIRE_VALID1 | \
+ EXT4_EXT_DATA_PARTIAL_VALID1)
+
+#define EXT4_EXT_DATA_VALID2 0x20 /* second half contains valid data */

static __le32 ext4_extent_block_csum(struct inode *inode,
struct ext4_extent_header *eh)
@@ -3175,8 +3180,9 @@ static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle,
unsigned int ee_len, depth;
int err = 0;

- BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
- (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
+ BUG_ON((split_flag & EXT4_EXT_DATA_VALID1) == EXT4_EXT_DATA_VALID1);
+ BUG_ON((split_flag & EXT4_EXT_DATA_VALID1) &&
+ (split_flag & EXT4_EXT_DATA_VALID2));

/* Do not cache extents that are in the process of being modified. */
flags |= EXT4_EX_NOCACHE;
@@ -3367,7 +3373,7 @@ static int ext4_split_extent(handle_t *handle,
split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
EXT4_EXT_MARK_UNWRIT2;
if (split_flag & EXT4_EXT_DATA_VALID2)
- split_flag1 |= EXT4_EXT_DATA_VALID1;
+ split_flag1 |= EXT4_EXT_DATA_ENTIRE_VALID1;
path = ext4_split_extent_at(handle, inode, path,
map->m_lblk + map->m_len, split_flag1, flags1);
if (IS_ERR(path)) {
@@ -3731,7 +3737,7 @@ static int ext4_split_convert_extents(handle_t *handle,

/* Convert to unwritten */
if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
- split_flag |= EXT4_EXT_DATA_VALID1;
+ split_flag |= EXT4_EXT_DATA_ENTIRE_VALID1;
/* Convert to initialized */
} else if (flags & EXT4_GET_BLOCKS_CONVERT) {
split_flag |= ee_block + ee_len <= eof_block ?
--
2.51.0