From b5f10eed8125702929e57cca7e5956b1b9b6d015 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Sat, 2 Aug 2008 21:21:08 -0400 Subject: ext4: lock block groups when initializing I noticed when filling a 1T filesystem with 4 threads using the fs_mark benchmark: fs_mark -d /mnt/test -D 256 -n 100000 -t 4 -s 20480 -F -S 0 that I occasionally got checksum mismatch errors: EXT4-fs error (device sdb): ext4_init_inode_bitmap: Checksum bad for group 6935 etc. I'd reliably get 4-5 of them during the run. It appears that the problem is likely a race to init the bg's when the uninit_bg feature is enabled. With the patch below, which adds sb_bgl_locking around initialization, I was able to complete several runs with no errors or warnings. Signed-off-by: Eric Sandeen Signed-off-by: Theodore Ts'o --- fs/ext4/balloc.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/ext4/balloc.c') diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index 386cb79ac4b..1ae5004e93f 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -321,12 +321,15 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) if (bh_uptodate_or_lock(bh)) return bh; + spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group)); if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { ext4_init_block_bitmap(sb, bh, block_group, desc); set_buffer_uptodate(bh); unlock_buffer(bh); + spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group)); return bh; } + spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group)); if (bh_submit_read(bh) < 0) { put_bh(bh); ext4_error(sb, __func__, -- cgit v1.2.3