| Message ID | 1370489283-4870-1-git-send-email-miaox@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Wednesday, June 05, 2013 Miao Xie wrote: > 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. This patch also fixed my problem. I tend to like this patch better as the fix lands on disk allowing nocow to function with an older kernel after being balanced. Thanks, Kyle Tested-by: Kyle Gates <kylegates@hotmail.com> > 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> > --- > fs/btrfs/relocation.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 44 insertions(+) > > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > index 395b820..934ffe6 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); > @@ -2273,8 +2281,12 @@ 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; > @@ -2308,12 +2320,44 @@ 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); > } > } > > -- > 1.8.1.4 > > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 395b820..934ffe6 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); @@ -2273,8 +2281,12 @@ 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; @@ -2308,12 +2320,44 @@ 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); } }