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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2009-09-06 17:49:49 +0900
committerRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2009-09-14 18:27:13 +0900
commit143511046765504d2d1be633efd710f8d84e0407 (patch)
treebd9b8570880cfda44a9fad7a2567b977ab53f631 /fs/nilfs2
parent027d6404eb4327878454db72a006adfcb8001bb8 (diff)
downloadlinux-143511046765504d2d1be633efd710f8d84e0407.tar.gz
nilfs2: always lookup disk block address before reading metadata block
The current metadata file code skips disk address lookup for its data block if the buffer has a mapped flag. This has a potential risk to cause read request to be performed against the stale block address that GC moved, and it may lead to meta data corruption. The mapped flag is safe if the buffer has an uptodate flag, otherwise it may prevent necessary update of disk address in the next read. This will avoid the potential problem by ensuring disk address lookup before reading metadata block even for buffers with the mapped flag. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Diffstat (limited to 'fs/nilfs2')
-rw-r--r--fs/nilfs2/mdt.c25
1 files changed, 10 insertions, 15 deletions
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index a5cd80162dc..1ae8d56052c 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -103,15 +103,12 @@ static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
goto failed_unlock;
err = -EEXIST;
- if (buffer_uptodate(bh) || buffer_mapped(bh))
+ if (buffer_uptodate(bh))
goto failed_bh;
-#if 0
- /* The uptodate flag is not protected by the page lock, but
- the mapped flag is. Thus, we don't have to wait the buffer. */
+
wait_on_buffer(bh);
if (buffer_uptodate(bh))
goto failed_bh;
-#endif
bh->b_bdev = nilfs->ns_bdev;
err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
@@ -162,17 +159,15 @@ nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
unlock_buffer(bh);
goto out;
}
- if (!buffer_mapped(bh)) { /* unused buffer */
- ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff,
- &blknum);
- if (unlikely(ret)) {
- unlock_buffer(bh);
- goto failed_bh;
- }
- bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev;
- bh->b_blocknr = blknum;
- set_buffer_mapped(bh);
+
+ ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
+ if (unlikely(ret)) {
+ unlock_buffer(bh);
+ goto failed_bh;
}
+ bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev;
+ bh->b_blocknr = blknum;
+ set_buffer_mapped(bh);
bh->b_end_io = end_buffer_read_sync;
get_bh(bh);