NFS: Add a helper to remove case-insensitive aliases

When dealing with case insensitive names, the client has no idea how the
server performs the mapping, so cannot collapse the dentries into a
single representative. So both rename and unlink need to deal with the
fact that there could be several dentries representing the file, and
have to somehow force them to be revalidated. Use d_prune_aliases() as a
big hammer approach.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index a691a1e364a7..d2a58f7a73a6 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1819,6 +1819,14 @@ out:
 }
 EXPORT_SYMBOL_GPL(nfs_lookup);
 
+void nfs_d_prune_case_insensitive_aliases(struct inode *inode)
+{
+	/* Case insensitive server? Revalidate dentries */
+	if (inode && nfs_server_capable(inode, NFS_CAP_CASE_INSENSITIVE))
+		d_prune_aliases(inode);
+}
+EXPORT_SYMBOL_GPL(nfs_d_prune_case_insensitive_aliases);
+
 #if IS_ENABLED(CONFIG_NFS_V4)
 static int nfs4_lookup_revalidate(struct dentry *, unsigned int);
 
@@ -2199,8 +2207,10 @@ static void nfs_dentry_remove_handle_error(struct inode *dir,
 	switch (error) {
 	case -ENOENT:
 		d_delete(dentry);
-		fallthrough;
+		nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
+		break;
 	case 0:
+		nfs_d_prune_case_insensitive_aliases(d_inode(dentry));
 		nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
 	}
 }