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Diffstat (limited to 'fs/ext4/inode.c')
-rw-r--r--fs/ext4/inode.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 558a585c5df5..6af572425596 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3859,7 +3859,11 @@ int ext4_can_truncate(struct inode *inode)
* We have to make sure i_disksize gets properly updated before we truncate
* page cache due to hole punching or zero range. Otherwise i_disksize update
* can get lost as it may have been postponed to submission of writeback but
- * that will never happen after we truncate page cache.
+ * that will never happen if we remove the folio containing i_size from the
+ * page cache. Also if we punch hole within i_size but above i_disksize,
+ * following ext4_page_mkwrite() may mistakenly allocate written blocks over
+ * the hole and thus introduce allocated blocks beyond i_disksize which is
+ * not allowed (e2fsck would complain in case of crash).
*/
int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
loff_t len)
@@ -3870,9 +3874,11 @@ int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
loff_t size = i_size_read(inode);
WARN_ON(!inode_is_locked(inode));
- if (offset > size || offset + len < size)
+ if (offset > size)
return 0;
+ if (offset + len < size)
+ size = offset + len;
if (EXT4_I(inode)->i_disksize >= size)
return 0;