Ext4: handle SEEK_HOLE/SEEK_DATA generically

Since Ext4 has its own lseek we need to make sure it handles
SEEK_HOLE/SEEK_DATA.  For now just do the same thing that is done in the generic
case, somebody else can come along and make it do fancy things later.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 21 insertions, 0 deletions

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 2c0972322009..ce766f974b1d 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -236,6 +236,27 @@ loff_t ext4_llseek(struct file *file, loff_t offset, int origin)
                 }
                 offset += file->f_pos;
                 break;
+        case SEEK_DATA:
+                /*
+                 * In the generic case the entire file is data, so as long as
+                 * offset isn't at the end of the file then the offset is data.
+                 */
+                if (offset >= inode->i_size) {
+                        mutex_unlock(&inode->i_mutex);
+                        return -ENXIO;
+                }
+                break;
+        case SEEK_HOLE:
+                /*
+                 * There is a virtual hole at the end of the file, so as long as
+                 * offset isn't i_size or larger, return i_size.
+                 */
+                if (offset >= inode->i_size) {
+                        mutex_unlock(&inode->i_mutex);
+                        return -ENXIO;
+                }
+                offset = inode->i_size;
+                break;
         }
 
         if (offset < 0 || offset > maxbytes) {