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authorFilipe Manana <fdmanana@suse.com>2016-08-01 03:50:37 +0300
committerFilipe Manana <fdmanana@suse.com>2016-08-01 09:31:41 +0300
commit951555856b88aa47bc238de6b4c6e97bfd9d36df (patch)
tree2c593dc8a659d69f5b92d6bfc3c7ba5b0fe2d046 /fs/btrfs/send.c
parent15b253eace1f98dabbc6e03f6793fcf8603b1655 (diff)
downloadlinux-951555856b88aa47bc238de6b4c6e97bfd9d36df.tar.xz
Btrfs: send, don't bug on inconsistent snapshots
When doing an incremental send, if we find a new/modified/deleted extent, reference or xattr without having previously processed the corresponding inode item we end up exexuting a BUG_ON(). This is because whenever an extent, xattr or reference is added, modified or deleted, we always expect to have the corresponding inode item updated. However there are situations where this will not happen due to transient -ENOMEM or -ENOSPC errors when doing delayed inode updates. For example, when punching holes we can succeed in deleting and modifying (shrinking) extents but later fail to do the delayed inode update. So after such failure we close our transaction handle and right after a snapshot of the fs/subvol tree can be made and used later for a send operation. The same thing can happen during truncate, link, unlink, and xattr related operations. So instead of executing a BUG_ON, make send return an -EIO error and print an informative error message do dmesg/syslog. Signed-off-by: Filipe Manana <fdmanana@suse.com>
Diffstat (limited to 'fs/btrfs/send.c')
-rw-r--r--fs/btrfs/send.c48
1 files changed, 45 insertions, 3 deletions
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 2db8dc89ca41..efe129fe2678 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -273,6 +273,39 @@ struct name_cache_entry {
char name[];
};
+static void inconsistent_snapshot_error(struct send_ctx *sctx,
+ enum btrfs_compare_tree_result result,
+ const char *what)
+{
+ const char *result_string;
+
+ switch (result) {
+ case BTRFS_COMPARE_TREE_NEW:
+ result_string = "new";
+ break;
+ case BTRFS_COMPARE_TREE_DELETED:
+ result_string = "deleted";
+ break;
+ case BTRFS_COMPARE_TREE_CHANGED:
+ result_string = "updated";
+ break;
+ case BTRFS_COMPARE_TREE_SAME:
+ ASSERT(0);
+ result_string = "unchanged";
+ break;
+ default:
+ ASSERT(0);
+ result_string = "unexpected";
+ }
+
+ btrfs_err(sctx->send_root->fs_info,
+ "Send: inconsistent snapshot, found %s %s for inode %llu without updated inode item, send root is %llu, parent root is %llu",
+ result_string, what, sctx->cmp_key->objectid,
+ sctx->send_root->root_key.objectid,
+ (sctx->parent_root ?
+ sctx->parent_root->root_key.objectid : 0));
+}
+
static int is_waiting_for_move(struct send_ctx *sctx, u64 ino);
static struct waiting_dir_move *
@@ -5711,7 +5744,10 @@ static int changed_ref(struct send_ctx *sctx,
{
int ret = 0;
- BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);
+ if (sctx->cur_ino != sctx->cmp_key->objectid) {
+ inconsistent_snapshot_error(sctx, result, "reference");
+ return -EIO;
+ }
if (!sctx->cur_inode_new_gen &&
sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) {
@@ -5736,7 +5772,10 @@ static int changed_xattr(struct send_ctx *sctx,
{
int ret = 0;
- BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);
+ if (sctx->cur_ino != sctx->cmp_key->objectid) {
+ inconsistent_snapshot_error(sctx, result, "xattr");
+ return -EIO;
+ }
if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
if (result == BTRFS_COMPARE_TREE_NEW)
@@ -5760,7 +5799,10 @@ static int changed_extent(struct send_ctx *sctx,
{
int ret = 0;
- BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);
+ if (sctx->cur_ino != sctx->cmp_key->objectid) {
+ inconsistent_snapshot_error(sctx, result, "extent");
+ return -EIO;
+ }
if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
if (result != BTRFS_COMPARE_TREE_DELETED)