From: Zheng Liu <wenqing.lz@xxxxxxxxxx>
This commit tries to improve ext4_es_can_be_merged. We check the length
of extent to avoid a potential overflow.
Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
---
fs/ext4/extents_status.c | 26 +++++++++++++++++++++-----
1 file changed, 21 insertions(+), 5 deletions(-)
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index f768f4a..a769485 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -329,17 +329,33 @@ static void ext4_es_free_extent(struct inode *inode, struct extent_status *es)
static int ext4_es_can_be_merged(struct extent_status *es1,
struct extent_status *es2)
{
- if (es1->es_lblk + es1->es_len != es2->es_lblk)
+ __u64 es1_len, es2_len, max_len;
+
+ if (ext4_es_status(es1) ^ ext4_es_status(es2))
return 0;
- if (ext4_es_status(es1) != ext4_es_status(es2))
+ max_len = 0xFFFFFFFFULL;
+ es1_len = es1->es_len;
+ es2_len = es2->es_len;
+
+ if (es1_len + es2_len > max_len)
return 0;
- if ((ext4_es_is_written(es1) || ext4_es_is_unwritten(es1)) &&
- (ext4_es_pblock(es1) + es1->es_len != ext4_es_pblock(es2)))
+ if (es1->es_lblk + es1_len != es2->es_lblk)
return 0;
- return 1;
+ if ((ext4_es_is_written(es1) || ext4_es_is_unwritten(es1)) &&
+ (ext4_es_pblock(es1) + es1_len == ext4_es_pblock(es2)))
+ return 1;
+
+ if (ext4_es_is_hole(es1))
+ return 1;
+
+ /* we need to check delayed extent is without unwritten status */
+ if (ext4_es_is_delayed(es1) && !ext4_es_is_unwritten(es1))
+ return 1;
+
+ return 0;
}
static struct extent_status *
--
1.7.12.rc2.18.g61b472e
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