From b5f10eed8125702929e57cca7e5956b1b9b6d015 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Sat, 2 Aug 2008 21:21:08 -0400 Subject: [PATCH] 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 +++ fs/ext4/ialloc.c | 5 ++++- fs/ext4/mballoc.c | 3 +++ fs/ext4/super.c | 2 ++ 4 files changed, 12 insertions(+), 1 deletion(-) 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__, diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 09cdcd5914d..655e760212b 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -118,12 +118,15 @@ ext4_read_inode_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_INODE_UNINIT)) { ext4_init_inode_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__, @@ -735,7 +738,7 @@ got: /* When marking the block group with * ~EXT4_BG_INODE_UNINIT we don't want to depend - * on the value of bg_itable_unsed even though + * on the value of bg_itable_unused even though * mke2fs could have initialized the same for us. * Instead we calculated the value below */ diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 8d141a25bbe..4258d3289a6 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -787,13 +787,16 @@ static int ext4_mb_init_cache(struct page *page, char *incore) if (bh_uptodate_or_lock(bh[i])) continue; + spin_lock(sb_bgl_lock(EXT4_SB(sb), first_group + i)); if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { ext4_init_block_bitmap(sb, bh[i], first_group + i, desc); set_buffer_uptodate(bh[i]); unlock_buffer(bh[i]); + spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i)); continue; } + spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i)); get_bh(bh[i]); bh[i]->b_end_io = end_buffer_read_sync; submit_bh(READ, bh[i]); diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 876e1c62036..511997ef6f0 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1621,6 +1621,7 @@ static int ext4_check_descriptors(struct super_block *sb) "(block %llu)!", i, inode_table); return 0; } + spin_lock(sb_bgl_lock(sbi, i)); if (!ext4_group_desc_csum_verify(sbi, i, gdp)) { printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: " "Checksum for group %lu failed (%u!=%u)\n", @@ -1629,6 +1630,7 @@ static int ext4_check_descriptors(struct super_block *sb) if (!(sb->s_flags & MS_RDONLY)) return 0; } + spin_unlock(sb_bgl_lock(sbi, i)); if (!flexbg_flag) first_block += EXT4_BLOCKS_PER_GROUP(sb); } -- 2.41.1