ext4: don't load the block bitmap for block groups which have no space
Add a short circuit check to ext4_mb_group_group() so that we don't
bother to load the block bitmap for a block group which does not have
any space available. (Or which does not have enough space until we
are in desperation mode, i.e., when cr == 3.)
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=45741
Reported-by: mirek@me.com
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 8eae947..3a57975 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1862,6 +1862,12 @@
BUG_ON(cr < 0 || cr >= 4);
+ free = grp->bb_free;
+ if (free == 0)
+ return 0;
+ if (cr <= 2 && free < ac->ac_g_ex.fe_len)
+ return 0;
+
/* We only do this if the grp has never been initialized */
if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
int ret = ext4_mb_init_group(ac->ac_sb, group);
@@ -1869,10 +1875,7 @@
return 0;
}
- free = grp->bb_free;
fragments = grp->bb_fragments;
- if (free == 0)
- return 0;
if (fragments == 0)
return 0;