Btrfs: Invalidate dcache entry after creating snapshot and
We need to invalidate an existing dcache entry after creating a new
snapshot or subvolume, because a negative dache entry will stop us from
accessing the new snapshot or subvolume.
---
ctree.h | 23 +++++++++++++++++++++++
inode.c | 4 ++++
transaction.c | 4 ++++
3 files changed, 31 insertions(+)
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1569fb8..31aa4ba 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2642,6 +2642,31 @@
btrfs_throttle(root);
}
+/*
+ * Invalidate a single dcache entry at the root of the filesystem.
+ * Needed after creation of snapshot or subvolume.
+ */
+void btrfs_invalidate_dcache_root(struct btrfs_root *root, char *name,
+ int namelen)
+{
+ struct dentry *alias, *entry;
+ struct qstr qstr;
+
+ alias = d_find_alias(root->fs_info->sb->s_root->d_inode);
+ if (alias) {
+ qstr.name = name;
+ qstr.len = namelen;
+ /* change me if btrfs ever gets a d_hash operation */
+ qstr.hash = full_name_hash(qstr.name, qstr.len);
+ entry = d_lookup(alias, &qstr);
+ dput(alias);
+ if (entry) {
+ d_invalidate(entry);
+ dput(entry);
+ }
+ }
+}
+
static int noinline create_subvol(struct btrfs_root *root, char *name,
int namelen)
{
@@ -2761,6 +2786,10 @@
ret = btrfs_update_inode(trans, new_root, inode);
if (ret)
goto fail;
+
+ /* Invalidate existing dcache entry for new subvolume. */
+ btrfs_invalidate_dcache_root(root, name, namelen);
+
fail:
nr = trans->blocks_used;
err = btrfs_commit_transaction(trans, new_root);