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-rw-r--r--fs/btrfs/ctree.h10
-rw-r--r--fs/btrfs/disk-io.c10
-rw-r--r--fs/btrfs/extent-tree.c10
-rw-r--r--fs/btrfs/relocation.c13
-rw-r--r--fs/btrfs/root-tree.c15
-rw-r--r--fs/btrfs/transaction.c33
-rw-r--r--fs/btrfs/transaction.h1
7 files changed, 91 insertions, 1 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 947f04789389..ebb2d109e8bb 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -602,6 +602,9 @@ enum {
/* Indicate that we want the transaction kthread to commit right now. */
BTRFS_FS_COMMIT_TRANS,
+ /* Indicate we have half completed snapshot deletions pending. */
+ BTRFS_FS_UNFINISHED_DROPS,
+
#if BITS_PER_LONG == 32
/* Indicate if we have error/warn message printed on 32bit systems */
BTRFS_FS_32BIT_ERROR,
@@ -1106,8 +1109,15 @@ enum {
BTRFS_ROOT_QGROUP_FLUSHING,
/* We started the orphan cleanup for this root. */
BTRFS_ROOT_ORPHAN_CLEANUP,
+ /* This root has a drop operation that was started previously. */
+ BTRFS_ROOT_UNFINISHED_DROP,
};
+static inline void btrfs_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
+{
+ clear_and_wake_up_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);
+}
+
/*
* Record swapped tree blocks of a subvolume tree for delayed subtree trace
* code. For detail check comment in fs/btrfs/qgroup.c.
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 87a5addbedf6..48590a380762 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3813,6 +3813,10 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
set_bit(BTRFS_FS_OPEN, &fs_info->flags);
+ /* Kick the cleaner thread so it'll start deleting snapshots. */
+ if (test_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags))
+ wake_up_process(fs_info->cleaner_kthread);
+
clear_oneshot:
btrfs_clear_oneshot_options(fs_info);
return 0;
@@ -4538,6 +4542,12 @@ void __cold close_ctree(struct btrfs_fs_info *fs_info)
*/
kthread_park(fs_info->cleaner_kthread);
+ /*
+ * If we had UNFINISHED_DROPS we could still be processing them, so
+ * clear that bit and wake up relocation so it can stop.
+ */
+ btrfs_wake_unfinished_drop(fs_info);
+
/* wait for the qgroup rescan worker to stop */
btrfs_qgroup_wait_for_completion(fs_info, false);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index d89273c4b6b8..96427b1ecac3 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5622,6 +5622,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
int ret;
int level;
bool root_dropped = false;
+ bool unfinished_drop = false;
btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
@@ -5664,6 +5665,8 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
* already dropped.
*/
set_bit(BTRFS_ROOT_DELETING, &root->state);
+ unfinished_drop = test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);
+
if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
level = btrfs_header_level(root->node);
path->nodes[level] = btrfs_lock_root_node(root);
@@ -5839,6 +5842,13 @@ out_free:
btrfs_free_path(path);
out:
/*
+ * We were an unfinished drop root, check to see if there are any
+ * pending, and if not clear and wake up any waiters.
+ */
+ if (!err && unfinished_drop)
+ btrfs_maybe_wake_unfinished_drop(fs_info);
+
+ /*
* So if we need to stop dropping the snapshot for whatever reason we
* need to make sure to add it back to the dead root list so that we
* keep trying to do the work later. This also cleans up roots if we
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index f5465197996d..9d8054839782 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3960,6 +3960,19 @@ int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
int rw = 0;
int err = 0;
+ /*
+ * This only gets set if we had a half-deleted snapshot on mount. We
+ * cannot allow relocation to start while we're still trying to clean up
+ * these pending deletions.
+ */
+ ret = wait_on_bit(&fs_info->flags, BTRFS_FS_UNFINISHED_DROPS, TASK_INTERRUPTIBLE);
+ if (ret)
+ return ret;
+
+ /* We may have been woken up by close_ctree, so bail if we're closing. */
+ if (btrfs_fs_closing(fs_info))
+ return -EINTR;
+
bg = btrfs_lookup_block_group(fs_info, group_start);
if (!bg)
return -ENOENT;
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 3d68d2dcd83e..ca7426ef61c8 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -278,6 +278,21 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state));
if (btrfs_root_refs(&root->root_item) == 0) {
+ struct btrfs_key drop_key;
+
+ btrfs_disk_key_to_cpu(&drop_key, &root->root_item.drop_progress);
+ /*
+ * If we have a non-zero drop_progress then we know we
+ * made it partly through deleting this snapshot, and
+ * thus we need to make sure we block any balance from
+ * happening until this snapshot is completely dropped.
+ */
+ if (drop_key.objectid != 0 || drop_key.type != 0 ||
+ drop_key.offset != 0) {
+ set_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);
+ set_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);
+ }
+
set_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
btrfs_add_dead_root(root);
}
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index c3cfdfd8de9b..f17bf3764ce8 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1320,6 +1320,32 @@ again:
}
/*
+ * If we had a pending drop we need to see if there are any others left in our
+ * dead roots list, and if not clear our bit and wake any waiters.
+ */
+void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
+{
+ /*
+ * We put the drop in progress roots at the front of the list, so if the
+ * first entry doesn't have UNFINISHED_DROP set we can wake everybody
+ * up.
+ */
+ spin_lock(&fs_info->trans_lock);
+ if (!list_empty(&fs_info->dead_roots)) {
+ struct btrfs_root *root = list_first_entry(&fs_info->dead_roots,
+ struct btrfs_root,
+ root_list);
+ if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) {
+ spin_unlock(&fs_info->trans_lock);
+ return;
+ }
+ }
+ spin_unlock(&fs_info->trans_lock);
+
+ btrfs_wake_unfinished_drop(fs_info);
+}
+
+/*
* dead roots are old snapshots that need to be deleted. This allocates
* a dirty root struct and adds it into the list of dead roots that need to
* be deleted
@@ -1331,7 +1357,12 @@ void btrfs_add_dead_root(struct btrfs_root *root)
spin_lock(&fs_info->trans_lock);
if (list_empty(&root->root_list)) {
btrfs_grab_root(root);
- list_add_tail(&root->root_list, &fs_info->dead_roots);
+
+ /* We want to process the partially complete drops first. */
+ if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state))
+ list_add(&root->root_list, &fs_info->dead_roots);
+ else
+ list_add_tail(&root->root_list, &fs_info->dead_roots);
}
spin_unlock(&fs_info->trans_lock);
}
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 9402d8d94484..ba8a9826eb37 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -216,6 +216,7 @@ int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid);
void btrfs_add_dead_root(struct btrfs_root *root);
int btrfs_defrag_root(struct btrfs_root *root);
+void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info);
int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root);
int btrfs_commit_transaction(struct btrfs_trans_handle *trans);
void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans);