[80/90] ext4: remove blocks from inode prealloc list on failure

Greg KH
2009-12-11T04:43:12Z

[-- Attachment #1: 0080-ext4-remove-blocks-from-inode-prealloc-list-on-failu.patch --]
[-- Type: text/plain, Size: 1576 bytes --]

2.6.31-stable review patch. If anyone has any objections, please let us know.

------------------
(cherry picked from commit b844167edc7fcafda9623955c05e4c1b3c32ebc7)

This fixes a leak of blocks in an inode prealloc list if device failures
cause ext4_mb_mark_diskspace_used() to fail.

Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Acked-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/ext4/mballoc.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3258,6 +3258,24 @@ static void ext4_mb_collect_stats(struct
}

/*
+ * Called on failure; free up any blocks from the inode PA for this
+ * context. We don't need this for MB_GROUP_PA because we only change
+ * pa_free in ext4_mb_release_context(), but on failure, we've already
+ * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
+ */
+static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
+{
+ struct ext4_prealloc_space *pa = ac->ac_pa;
+ int len;
+
+ if (pa && pa->pa_type == MB_INODE_PA) {
+ len = ac->ac_b_ex.fe_len;
+ pa->pa_free += len;
+ }
+
+}
+
+/*
* use blocks preallocated to inode
*/
static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
@@ -4546,6 +4564,7 @@ repeat:
ac->ac_status = AC_STATUS_CONTINUE;
goto repeat;
} else if (*errp) {
+ ext4_discard_allocated_blocks(ac);
ac->ac_b_ex.fe_len = 0;
ar->len = 0;
ext4_mb_show_ac(ac);