From patchwork Fri Aug 10 18:21:25 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: ext4: don't load the block bitmap for block groups which have no space From: Theodore Ts'o X-Patchwork-Id: 176578 Message-Id: <1344622885-14982-1-git-send-email-tytso@mit.edu> To: Ext4 Developers List Cc: Theodore Ts'o Date: Fri, 10 Aug 2012 14:21:25 -0400 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" --- fs/ext4/mballoc.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) 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 @@ static int ext4_mb_good_group(struct ext4_allocation_context *ac, 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 @@ static int ext4_mb_good_group(struct ext4_allocation_context *ac, return 0; } - free = grp->bb_free; fragments = grp->bb_fragments; - if (free == 0) - return 0; if (fragments == 0) return 0;