NFS: Implement SEEK

The SEEK operation is used when an application makes an lseek call with
either the SEEK_HOLE or SEEK_DATA flags set.  I fall back on
nfs_file_llseek() if the server does not have SEEK support.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index a816f0627a6c..4dffa3a64731 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -8,6 +8,10 @@
 #include "fscache.h"
 #include "pnfs.h"
 
+#ifdef CONFIG_NFS_V4_2
+#include "nfs42.h"
+#endif
+
 #define NFSDBG_FACILITY         NFSDBG_FILE
 
 static int
@@ -115,8 +119,29 @@ nfs4_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
         return ret;
 }
 
+#ifdef CONFIG_NFS_V4_2
+static loff_t nfs4_file_llseek(struct file *filep, loff_t offset, int whence)
+{
+        loff_t ret;
+
+        switch (whence) {
+        case SEEK_HOLE:
+        case SEEK_DATA:
+                ret = nfs42_proc_llseek(filep, offset, whence);
+                if (ret != -ENOTSUPP)
+                        return ret;
+        default:
+                return nfs_file_llseek(filep, offset, whence);
+        }
+}
+#endif /* CONFIG_NFS_V4_2 */
+
 const struct file_operations nfs4_file_operations = {
+#ifdef CONFIG_NFS_V4_2
+        .llseek         = nfs4_file_llseek,
+#else
         .llseek         = nfs_file_llseek,
+#endif
         .read           = new_sync_read,
         .write          = new_sync_write,
         .read_iter      = nfs_file_read,