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| author | Miao Xie <miaox@cn.fujitsu.com> | 2013-06-06 03:28:03 +0000 |
|---|---|---|
| committer | Josef Bacik <jbacik@fusionio.com> | 2013-07-01 08:52:25 -0400 |
| commit | 5bc7247ac47cf100309e4d7e24214889c46a1636 (patch) | |
| tree | 2e28c383acea82994e54c330ba7345b436b69656 | |
| parent | 8c2a1a3028d560cfb95f1c583e872c65ed2f0b3d (diff) | |
| download | linux-5bc7247ac47cf100309e4d7e24214889c46a1636.tar.bz2 | |
Btrfs: fix broken nocow after balance
Balance will create reloc_root for each fs root, and it's going to
record last_snapshot to filter shared blocks. The side effect of
setting last_snapshot is to break nocow attributes of files.
Since the extents are not shared by the relocation tree after the balance,
we can recover the old last_snapshot safely if no one snapshoted the
source tree. We fix the above problem by this way.
Reported-by: Kyle Gates <kylegates@hotmail.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
| -rw-r--r-- | fs/btrfs/relocation.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index aa559f1161df..4a404b44b0ad 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -1305,6 +1305,7 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, struct extent_buffer *eb; struct btrfs_root_item *root_item; struct btrfs_key root_key; + u64 last_snap = 0; int ret; root_item = kmalloc(sizeof(*root_item), GFP_NOFS); @@ -1320,6 +1321,7 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, BTRFS_TREE_RELOC_OBJECTID); BUG_ON(ret); + last_snap = btrfs_root_last_snapshot(&root->root_item); btrfs_set_root_last_snapshot(&root->root_item, trans->transid - 1); } else { @@ -1345,6 +1347,12 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, memset(&root_item->drop_progress, 0, sizeof(struct btrfs_disk_key)); root_item->drop_level = 0; + /* + * abuse rtransid, it is safe because it is impossible to + * receive data into a relocation tree. + */ + btrfs_set_root_rtransid(root_item, last_snap); + btrfs_set_root_otransid(root_item, trans->transid); } btrfs_tree_unlock(eb); @@ -2272,8 +2280,12 @@ void free_reloc_roots(struct list_head *list) static noinline_for_stack int merge_reloc_roots(struct reloc_control *rc) { + struct btrfs_trans_handle *trans; struct btrfs_root *root; struct btrfs_root *reloc_root; + u64 last_snap; + u64 otransid; + u64 objectid; LIST_HEAD(reloc_roots); int found = 0; int ret = 0; @@ -2307,12 +2319,44 @@ again: } else { list_del_init(&reloc_root->root_list); } + + /* + * we keep the old last snapshod transid in rtranid when we + * created the relocation tree. + */ + last_snap = btrfs_root_rtransid(&reloc_root->root_item); + otransid = btrfs_root_otransid(&reloc_root->root_item); + objectid = reloc_root->root_key.offset; + ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1); if (ret < 0) { if (list_empty(&reloc_root->root_list)) list_add_tail(&reloc_root->root_list, &reloc_roots); goto out; + } else if (!ret) { + /* + * recover the last snapshot tranid to avoid + * the space balance break NOCOW. + */ + root = read_fs_root(rc->extent_root->fs_info, + objectid); + if (IS_ERR(root)) + continue; + + if (btrfs_root_refs(&root->root_item) == 0) + continue; + + trans = btrfs_join_transaction(root); + BUG_ON(IS_ERR(trans)); + + /* Check if the fs/file tree was snapshoted or not. */ + if (btrfs_root_last_snapshot(&root->root_item) == + otransid - 1) + btrfs_set_root_last_snapshot(&root->root_item, + last_snap); + + btrfs_end_transaction(trans, root); } } |