[ 049/187] nilfs2: ensure proper cache clearing for gc-inodes

Greg Kroah-Hartman
2012-07-12T23:41:45Z

From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

commit fbb24a3a915f105016f1c828476be11aceac8504 upstream.

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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nilfs2/gcinode.c | 2 ++
fs/nilfs2/segment.c | 2 ++
2 files changed, 4 insertions(+)

--- a/fs/nilfs2/gcinode.c
+++ b/fs/nilfs2/gcinode.c
@@ -191,6 +191,8 @@ void nilfs_remove_all_gcinodes(struct th
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);
}
}
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2309,6 +2309,8 @@ nilfs_remove_written_gcinodes(struct the
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);
}
}