nilfs2: ensure proper cache clearing for gc-inodes

A gc-inode is a pseudo inode used to buffer the blocks to be moved by
garbage collection.

Block caches of gc-inodes must be cleared every time a garbage collection
function (nilfs_clean_segments) completes.  Otherwise, stale blocks
buffered in the caches may be wrongly reused in successive calls of the GC
function.

For user files, this is not a problem because their gc-inodes are
distinguished by a checkpoint number as well as an inode number.  They
never buffer different blocks if either an inode number, a checkpoint
number, or a block offset differs.

However, gc-inodes of sufile, cpfile and DAT file can store different data
for the same block offset.  Thus, the nilfs_clean_segments function can
move incorrect block for these meta-data files if an old block is cached.
I found this is really causing meta-data corruption in nilfs.

This fixes the issue by ensuring cache clear of gc-inodes and resolves
reported GC problems including checkpoint file corruption, b-tree
corruption, and the following warning during GC.

  nilfs_palloc_freev: entry number 307234 already freed.
  ...

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>	[2.6.37+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ryusuke Konishi 2012-06-20 12:52:57 -07:00 committed by Linus Torvalds
parent e4eed03fd0
commit fbb24a3a91
2 changed files with 4 additions and 0 deletions

View file

@ -191,6 +191,8 @@ void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs)
while (!list_empty(head)) {
ii = list_first_entry(head, struct nilfs_inode_info, i_dirty);
list_del_init(&ii->i_dirty);
truncate_inode_pages(&ii->vfs_inode.i_data, 0);
nilfs_btnode_cache_clear(&ii->i_btnode_cache);
iput(&ii->vfs_inode);
}
}

View file

@ -2309,6 +2309,8 @@ nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
continue;
list_del_init(&ii->i_dirty);
truncate_inode_pages(&ii->vfs_inode.i_data, 0);
nilfs_btnode_cache_clear(&ii->i_btnode_cache);
iput(&ii->vfs_inode);
}
}