[RFC PATCH 1/2] ceph: factor out ceph_lookup_inode()

[Luis Henriques <lhenriques@suse.com>]

This function will be used by __fh_to_dentry and by the quotas code, to find
quota realm inodes that are not visible in the mountpoint.  The only
functional change is that an error is also returned if ceph_mdsc_do_request()
fails.

Signed-off-by: Luis Henriques <lhenriques@suse.com>
---
 fs/ceph/export.c | 14 +++++++++++++-
 fs/ceph/super.h  |  1 +
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/export.c b/fs/ceph/export.c
index 3c59ad180ef0..0d8ead82c816 100644
--- a/fs/ceph/export.c
+++ b/fs/ceph/export.c
@@ -59,7 +59,7 @@ static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
 	return type;
 }
 
-static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
+struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino)
 {
 	struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
 	struct inode *inode;
@@ -92,12 +92,24 @@ static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
 		ceph_mdsc_put_request(req);
 		if (!inode)
 			return ERR_PTR(-ESTALE);
+		if (err)
+			return ERR_PTR(err);
 		if (inode->i_nlink == 0) {
 			iput(inode);
 			return ERR_PTR(-ESTALE);
 		}
 	}
 
+	return inode;
+}
+
+static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
+{
+	struct inode *inode = ceph_lookup_inode(sb, ino);
+
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+
 	return d_obtain_alias(inode);
 }
 
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index dfb64a5211b6..ce51e98b08ec 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1061,6 +1061,7 @@ extern long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 
 /* export.c */
 extern const struct export_operations ceph_export_ops;
+struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino);
 
 /* locks.c */
 extern __init void ceph_flock_init(void);