[PATCH 11/17] vfs: replace calling i_op->readlink with vfs_readlink()

[Miklos Szeredi]

At this point all ->readlink instances are set to generic_readlink.  So
instead of calling i_op->readlink, we can call generic_readlink directly.

Add an alias for generic_readlink(): vfs_readlink().  They are exactly the
same but result in consistent naming.  We can get rid of generic_readlink()
after the next patch.

Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
 fs/ecryptfs/inode.c    | 4 +---
 fs/nfsd/nfs4xdr.c      | 8 ++++----
 fs/nfsd/vfs.c          | 4 ++--
 fs/overlayfs/copy_up.c | 5 ++---
 fs/stat.c              | 5 ++---
 fs/xfs/xfs_ioctl.c     | 4 ++--
 include/linux/fs.h     | 6 ++++++
 7 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 9d153b6a1d72..9885a8f88260 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -638,9 +638,7 @@ static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 		return ERR_PTR(-ENOMEM);
 	old_fs = get_fs();
 	set_fs(get_ds());
-	rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
-						   (char __user *)lower_buf,
-						   PATH_MAX);
+	rc = vfs_readlink(lower_dentry, (char __user *)lower_buf, PATH_MAX);
 	set_fs(old_fs);
 	if (rc < 0)
 		goto out;
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 0aa0236a1429..623268f32ee2 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3552,10 +3552,10 @@ nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd
 	if (!p)
 		return nfserr_resource;
 	/*
-	 * XXX: By default, the ->readlink() VFS op will truncate symlinks
-	 * if they would overflow the buffer.  Is this kosher in NFSv4?  If
-	 * not, one easy fix is: if ->readlink() precisely fills the buffer,
-	 * assume that truncation occurred, and return NFS4ERR_RESOURCE.
+	 * XXX: By default, vfs_readlink() will truncate symlinks if they
+	 * would overflow the buffer.  Is this kosher in NFSv4?  If not, one
+	 * easy fix is: if vfs_readlink() precisely fills the buffer, assume
+	 * that truncation occurred, and return NFS4ERR_RESOURCE.
 	 */
 	nfserr = nfsd_readlink(readlink->rl_rqstp, readlink->rl_fhp,
 						(char *)p, &maxcount);
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index ff476e654b8f..196620e1dc71 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1450,7 +1450,7 @@ nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
 	inode = d_inode(path.dentry);
 
 	err = nfserr_inval;
-	if (!inode->i_op->readlink)
+	if (!inode->i_op->get_link)
 		goto out;
 
 	touch_atime(&path);
@@ -1459,7 +1459,7 @@ nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
 	 */
 
 	oldfs = get_fs(); set_fs(KERNEL_DS);
-	host_err = inode->i_op->readlink(path.dentry, (char __user *)buf, *lenp);
+	host_err = vfs_readlink(path.dentry, (char __user *)buf, *lenp);
 	set_fs(oldfs);
 
 	if (host_err < 0)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 43fdc2765aea..a2d4c10dd74d 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -175,7 +175,7 @@ static char *ovl_read_symlink(struct dentry *realdentry)
 	mm_segment_t old_fs;
 
 	res = -EINVAL;
-	if (!inode->i_op->readlink)
+	if (!inode->i_op->get_link)
 		goto err;
 
 	res = -ENOMEM;
@@ -186,8 +186,7 @@ static char *ovl_read_symlink(struct dentry *realdentry)
 	old_fs = get_fs();
 	set_fs(get_ds());
 	/* The cast to a user pointer is valid due to the set_fs() */
-	res = inode->i_op->readlink(realdentry,
-				    (char __user *)buf, PAGE_SIZE - 1);
+	res = vfs_readlink(realdentry, (char __user *)buf, PAGE_SIZE - 1);
 	set_fs(old_fs);
 	if (res < 0) {
 		free_page((unsigned long) buf);
diff --git a/fs/stat.c b/fs/stat.c
index bc045c7994e1..a9bf2e8db854 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -329,12 +329,11 @@ retry:
 		struct inode *inode = d_backing_inode(path.dentry);
 
 		error = empty ? -ENOENT : -EINVAL;
-		if (inode->i_op->readlink) {
+		if (inode->i_op->get_link) {
 			error = security_inode_readlink(path.dentry);
 			if (!error) {
 				touch_atime(&path);
-				error = inode->i_op->readlink(path.dentry,
-							      buf, bufsiz);
+				error = vfs_readlink(path.dentry, buf, bufsiz);
 			}
 		}
 		path_put(&path);
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 96a70fd1f5d6..e8fdac738dc4 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -287,7 +287,7 @@ xfs_readlink_by_handle(
 		return PTR_ERR(dentry);
 
 	/* Restrict this handle operation to symlinks only. */
-	if (!d_inode(dentry)->i_op->readlink) {
+	if (!d_inode(dentry)->i_op->get_link) {
 		error = -EINVAL;
 		goto out_dput;
 	}
@@ -297,7 +297,7 @@ xfs_readlink_by_handle(
 		goto out_dput;
 	}
 
-	error = d_inode(dentry)->i_op->readlink(dentry, hreq->ohandle, olen);
+	error = vfs_readlink(dentry, hreq->ohandle, olen);
 
  out_dput:
 	dput(dentry);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5448a9b88c41..bcb0bc774cb6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2919,6 +2919,12 @@ extern int vfs_lstat(const char __user *, struct kstat *);
 extern int vfs_fstat(unsigned int, struct kstat *);
 extern int vfs_fstatat(int , const char __user *, struct kstat *, int);
 
+static inline int vfs_readlink(struct dentry *dentry, char __user *buffer,
+			       int buflen)
+{
+	return generic_readlink(dentry, buffer, buflen);
+}
+
 extern int __generic_block_fiemap(struct inode *inode,
 				  struct fiemap_extent_info *fieinfo,
 				  loff_t start, loff_t len,
-- 
2.5.5