Btrfs: fix btrfs_ordered_update_i_size to update disk_i_size properly
btrfs_ordered_update_i_size can be called by truncate and endio, but
only endio takes ordered_extent which contains the completed IO.
while truncating down a file, if there are some in-flight IOs,
btrfs_ordered_update_i_size in endio will set disk_i_size to
@orig_offset that is zero. If truncating-down fails somehow, we try to
recover in memory isize with this zero'd disk_i_size.
Fix it by only updating disk_i_size with @orig_offset when
btrfs_ordered_update_i_size is not called from endio while truncating
down and waiting for in-flight IOs completing their work before recover
in-memory size.
Besides fixing the above issue, add an assertion for last_size to double
check we truncate down to the desired size.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 7ae350a..2cdf016 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -984,8 +984,18 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
}
disk_i_size = BTRFS_I(inode)->disk_i_size;
- /* truncate file */
- if (disk_i_size > i_size) {
+ /*
+ * truncate file.
+ * If ordered is not NULL, then this is called from endio and
+ * disk_i_size will be updated by either truncate itself or any
+ * in-flight IOs which are inside the disk_i_size.
+ *
+ * Because btrfs_setsize() may set i_size with disk_i_size if truncate
+ * fails somehow, we need to make sure we have a precise disk_i_size by
+ * updating it as usual.
+ *
+ */
+ if (!ordered && disk_i_size > i_size) {
BTRFS_I(inode)->disk_i_size = orig_offset;
ret = 0;
goto out;