Filipe David Borba Manana
2014-May-25 02:43 UTC
[PATCH] Btrfs: send, don't error in the presence of subvols/snapshots
If we are doing an incremental send and the base snapshot has a
directory with name X that doesn't exist anymore in the second
snapshot and a new subvolume/snapshot exists in the second snapshot
that has the same name as the directory (name X), the incremental
send would fail with -ENOENT error. This is because it attempts
to lookup for an inode with a number matching the objectid of a
root, which doesn't exist.
Steps to reproduce:
mkfs.btrfs -f /dev/sdd
mount /dev/sdd /mnt
mkdir /mnt/testdir
btrfs subvolume snapshot -r /mnt /mnt/mysnap1
rmdir /mnt/testdir
btrfs subvolume create /mnt/testdir
btrfs subvolume snapshot -r /mnt /mnt/mysnap2
btrfs send -p /mnt/mysnap1 /mnt/mysnap2 -f /tmp/send.data
A test case for xfstests follows.
Reported-by: Robert White <rwhite@pobox.com>
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
---
fs/btrfs/send.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 1a65a40..f51525e 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -1642,7 +1642,8 @@ out:
static int lookup_dir_item_inode(struct btrfs_root *root,
u64 dir, const char *name, int name_len,
u64 *found_inode,
- u8 *found_type)
+ u8 *found_type,
+ int *found_is_root)
{
int ret = 0;
struct btrfs_dir_item *di;
@@ -1666,6 +1667,8 @@ static int lookup_dir_item_inode(struct btrfs_root *root,
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
*found_inode = key.objectid;
*found_type = btrfs_dir_type(path->nodes[0], di);
+ if (found_is_root)
+ *found_is_root = (key.type == BTRFS_ROOT_ITEM_KEY);
out:
btrfs_free_path(path);
@@ -1816,7 +1819,7 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64
dir, u64 dir_gen,
}
ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
- &other_inode, &other_type);
+ &other_inode, &other_type, NULL);
if (ret < 0 && ret != -ENOENT)
goto out;
if (ret) {
@@ -1861,6 +1864,7 @@ static int did_overwrite_ref(struct send_ctx *sctx,
u64 gen;
u64 ow_inode;
u8 other_type;
+ int other_is_root = 0;
if (!sctx->parent_root)
goto out;
@@ -1871,10 +1875,10 @@ static int did_overwrite_ref(struct send_ctx *sctx,
/* check if the ref was overwritten by another ref */
ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
- &ow_inode, &other_type);
+ &ow_inode, &other_type, &other_is_root);
if (ret < 0 && ret != -ENOENT)
goto out;
- if (ret) {
+ if (ret || other_is_root) {
/* was never and will never be overwritten */
ret = 0;
goto out;
--
1.9.1
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