udf: Fix loading of special inodes

Some UDF media have special inodes (like VAT or metadata partition
inodes) whose link_count is 0. Thus commit 4071b9136223 (udf: Properly
detect stale inodes) broke loading these inodes because udf_iget()
started returning -ESTALE for them. Since we still need to properly
detect stale inodes queried by NFS, create two variants of udf_iget() -
one which is used for looking up special inodes (which ignores
link_count == 0) and one which is used for other cases which return
ESTALE when link_count == 0.

Fixes: 4071b913622316970d0e1919f7d82b4403fec5f2
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 9 insertions, 5 deletions

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 08598843288f..c9b4df5810d5 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1277,7 +1277,7 @@ update_time:
  */
 #define UDF_MAX_ICB_NESTING 1024
 
-static int udf_read_inode(struct inode *inode)
+static int udf_read_inode(struct inode *inode, bool hidden_inode)
 {
         struct buffer_head *bh = NULL;
         struct fileEntry *fe;
@@ -1436,8 +1436,11 @@ reread:
 
         link_count = le16_to_cpu(fe->fileLinkCount);
         if (!link_count) {
-                ret = -ESTALE;
-                goto out;
+                if (!hidden_inode) {
+                        ret = -ESTALE;
+                        goto out;
+                }
+                link_count = 1;
         }
         set_nlink(inode, link_count);
 
@@ -1826,7 +1829,8 @@ out:
         return err;
 }
 
-struct inode *udf_iget(struct super_block *sb, struct kernel_lb_addr *ino)
+struct inode *__udf_iget(struct super_block *sb, struct kernel_lb_addr *ino,
+                         bool hidden_inode)
 {
         unsigned long block = udf_get_lb_pblock(sb, ino, 0);
         struct inode *inode = iget_locked(sb, block);
@@ -1839,7 +1843,7 @@ struct inode *udf_iget(struct super_block *sb, struct kernel_lb_addr *ino)
                 return inode;
 
         memcpy(&UDF_I(inode)->i_location, ino, sizeof(struct kernel_lb_addr));
-        err = udf_read_inode(inode);
+        err = udf_read_inode(inode, hidden_inode);
         if (err < 0) {
                 iget_failed(inode);
                 return ERR_PTR(err);