len is 0 means no extent needs to be removed, so return immediately.
Otherwise it could trigger the following BUG_ON()
436 end = offset + len - 1;
437 BUG_ON(end < offset);
This could be reproduced by a simple truncate(1) command by an
unprivileged user
truncate -s $(($((2**32 - 1)) * 4096)) /mnt/ext4/testfile
The same is true for __es_insert_extent().
Patched kernel passed xfstests regression test.
Also remove comments about EXT4_I(inode)->i_es_lock, this rwlock
isn't hold by callers.
Cc: Zheng Liu <wenqing.lz@xxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Signed-off-by: Eryu Guan <guaneryu@xxxxxxxxx>
---
fs/ext4/extents_status.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 564d981..3ac09ca 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -328,6 +328,9 @@ static int __es_insert_extent(struct ext4_es_tree *tree, ext4_lblk_t offset,
struct extent_status *es;
ext4_lblk_t end = offset + len - 1;
+ if (!len)
+ return 0;
+
BUG_ON(end < offset);
es = tree->cache_es;
if (es && offset == (extent_status_end(es) + 1)) {
@@ -386,7 +389,6 @@ out:
/*
* ext4_es_insert_extent() adds a space to a delayed extent tree.
- * Caller holds inode->i_es_lock.
*
* ext4_es_insert_extent is called by ext4_da_write_begin and
* ext4_es_remove_extent.
@@ -415,7 +417,6 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t offset,
/*
* ext4_es_remove_extent() removes a space from a delayed extent tree.
- * Caller holds inode->i_es_lock.
*
* Return 0 on success, error code on failure.
*/
@@ -433,6 +434,9 @@ int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t offset,
es_debug("remove [%u/%u) from extent status tree of inode %lu\n",
offset, len, inode->i_ino);
+ if (!len)
+ return err;
+
end = offset + len - 1;
BUG_ON(end < offset);
write_lock(&EXT4_I(inode)->i_es_lock);
--
1.8.1.2
--
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