vfs: make unlink() and rmdir() return ENOENT in preference to EROFS

If user space attempts to remove a non-existent file or directory, and
the file system is mounted read-only, return ENOENT instead of EROFS.
Either error code is arguably valid/correct, but ENOENT is a more
specific error message.

Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 7 insertions, 4 deletions

diff --git a/fs/namei.c b/fs/namei.c
index e2e4e8d032ee..9802345df5e7 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2624,6 +2624,10 @@ static long do_rmdir(int dfd, const char __user *pathname)
         error = PTR_ERR(dentry);
         if (IS_ERR(dentry))
                 goto exit2;
+        if (!dentry->d_inode) {
+                error = -ENOENT;
+                goto exit3;
+        }
         error = mnt_want_write(nd.path.mnt);
         if (error)
                 goto exit3;
@@ -2709,11 +2713,10 @@ static long do_unlinkat(int dfd, const char __user *pathname)
         error = PTR_ERR(dentry);
         if (!IS_ERR(dentry)) {
                 /* Why not before? Because we want correct error value */
-                if (nd.last.name[nd.last.len])
-                        goto slashes;
                 inode = dentry->d_inode;
-                if (inode)
-                        ihold(inode);
+                if (nd.last.name[nd.last.len] || !inode)
+                        goto slashes;
+                ihold(inode);
                 error = mnt_want_write(nd.path.mnt);
                 if (error)
                         goto exit2;