ocfs2: Implement llseek()
ocfs2 implements its own llseek() to provide the SEEK_HOLE/SEEK_DATA
functionality.
SEEK_HOLE sets the file pointer to the start of either a hole or an unwritten
(preallocated) extent, that is greater than or equal to the supplied offset.
SEEK_DATA sets the file pointer to the start of an allocated extent (not
unwritten) that is greater than or equal to the supplied offset.
If the supplied offset is on a desired region, then the file pointer is set
to it. Offsets greater than or equal to the file size return -ENXIO.
Unwritten (preallocated) extents are considered holes because the file system
treats reads to such regions in the same way as it does to holes.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 0fc2bd3..c0f015e 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2591,6 +2591,57 @@
return ret;
}
+/* Refer generic_file_llseek_unlocked() */
+static loff_t ocfs2_file_llseek(struct file *file, loff_t offset, int origin)
+{
+ struct inode *inode = file->f_mapping->host;
+ int ret = 0;
+
+ mutex_lock(&inode->i_mutex);
+
+ switch (origin) {
+ case SEEK_SET:
+ break;
+ case SEEK_END:
+ offset += inode->i_size;
+ break;
+ case SEEK_CUR:
+ if (offset == 0) {
+ offset = file->f_pos;
+ goto out;
+ }
+ offset += file->f_pos;
+ break;
+ case SEEK_DATA:
+ case SEEK_HOLE:
+ ret = ocfs2_seek_data_hole_offset(file, &offset, origin);
+ if (ret)
+ goto out;
+ break;
+ default:
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET))
+ ret = -EINVAL;
+ if (!ret && offset > inode->i_sb->s_maxbytes)
+ ret = -EINVAL;
+ if (ret)
+ goto out;
+
+ if (offset != file->f_pos) {
+ file->f_pos = offset;
+ file->f_version = 0;
+ }
+
+out:
+ mutex_unlock(&inode->i_mutex);
+ if (ret)
+ return ret;
+ return offset;
+}
+
const struct inode_operations ocfs2_file_iops = {
.setattr = ocfs2_setattr,
.getattr = ocfs2_getattr,
@@ -2615,7 +2666,7 @@
* ocfs2_fops_no_plocks and ocfs2_dops_no_plocks!
*/
const struct file_operations ocfs2_fops = {
- .llseek = generic_file_llseek,
+ .llseek = ocfs2_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.mmap = ocfs2_mmap,
@@ -2663,7 +2714,7 @@
* the cluster.
*/
const struct file_operations ocfs2_fops_no_plocks = {
- .llseek = generic_file_llseek,
+ .llseek = ocfs2_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.mmap = ocfs2_mmap,