fs: Simplify getattr interface function checking AT_GETATTR_NOSEC flag

Commit 8a924db2d7b5 ("fs: Pass AT_GETATTR_NOSEC flag to getattr interface
function")' introduced the AT_GETATTR_NOSEC flag to ensure that the
call paths only call vfs_getattr_nosec if it is set instead of vfs_getattr.
Now, simplify the getattr interface functions of filesystems where the flag
AT_GETATTR_NOSEC is checked.

There is only a single caller of inode_operations getattr function and it
is located in fs/stat.c in vfs_getattr_nosec. The caller there is the only
one from which the AT_GETATTR_NOSEC flag is passed from.

Two filesystems are checking this flag in .getattr and the flag is always
passed to them unconditionally from only vfs_getattr_nosec:

- ecryptfs:  Simplify by always calling vfs_getattr_nosec in
             ecryptfs_getattr. From there the flag is passed to no other
             function and this function is not called otherwise.

- overlayfs: Simplify by always calling vfs_getattr_nosec in
             ovl_getattr. From there the flag is passed to no other
             function and this function is not called otherwise.

The query_flags in vfs_getattr_nosec will mask-out AT_GETATTR_NOSEC from
any caller using AT_STATX_SYNC_TYPE as mask so that the flag is not
important inside this function. Also, since no filesystem is checking the
flag anymore, remove the flag entirely now, including the BUG_ON check that
never triggered.

The net change of the changes here combined with the original commit is
that ecryptfs and overlayfs do not call vfs_getattr but only
vfs_getattr_nosec.

Fixes: 8a924db2d7b5 ("fs: Pass AT_GETATTR_NOSEC flag to getattr interface function")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Closes: https://lore.kernel.org/linux-fsdevel/20241101011724.GN1350452@ZenIV/T/#u
Cc: Tyler Hicks <code@tyhicks.com>
Cc: ecryptfs@vger.kernel.org
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: linux-unionfs@vger.kernel.org
Cc: Christian Brauner <brauner@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 5 insertions, 13 deletions

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 35fd3e3e1778..8b31f44c12cd 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -170,7 +170,7 @@ int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
 
 	type = ovl_path_real(dentry, &realpath);
 	old_cred = ovl_override_creds(dentry->d_sb);
-	err = ovl_do_getattr(&realpath, stat, request_mask, flags);
+	err = vfs_getattr_nosec(&realpath, stat, request_mask, flags);
 	if (err)
 		goto out;
 
@@ -195,8 +195,8 @@ int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
 					(!is_dir ? STATX_NLINK : 0);
 
 			ovl_path_lower(dentry, &realpath);
-			err = ovl_do_getattr(&realpath, &lowerstat, lowermask,
-					     flags);
+			err = vfs_getattr_nosec(&realpath, &lowerstat, lowermask,
+						flags);
 			if (err)
 				goto out;
 
@@ -248,8 +248,8 @@ int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
 
 			ovl_path_lowerdata(dentry, &realpath);
 			if (realpath.dentry) {
-				err = ovl_do_getattr(&realpath, &lowerdatastat,
-						     lowermask, flags);
+				err = vfs_getattr_nosec(&realpath, &lowerdatastat,
+							lowermask, flags);
 				if (err)
 					goto out;
 			} else {
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 0bfe35da4b7b..910dbbb2bb7b 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -412,14 +412,6 @@ static inline bool ovl_open_flags_need_copy_up(int flags)
 	return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
 }
 
-static inline int ovl_do_getattr(const struct path *path, struct kstat *stat,
-				 u32 request_mask, unsigned int flags)
-{
-	if (flags & AT_GETATTR_NOSEC)
-		return vfs_getattr_nosec(path, stat, request_mask, flags);
-	return vfs_getattr(path, stat, request_mask, flags);
-}
-
 /* util.c */
 int ovl_get_write_access(struct dentry *dentry);
 void ovl_put_write_access(struct dentry *dentry);