Add SEEK_DATA/SEEK_HOLE to lseek()/llseek()

[zfs.git] / module / zfs / zfs_vnops.c

diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index 3b671b4..3c3e8db 100644 (file)
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -240,6 +240,68 @@ zfs_close(struct inode *ip, int flag, cred_t *cr)
 }
 EXPORT_SYMBOL(zfs_close);
 
+#if defined(SEEK_HOLE) && defined(SEEK_DATA)
+/*
+ * Lseek support for finding holes (cmd == SEEK_HOLE) and
+ * data (cmd == SEEK_DATA). "off" is an in/out parameter.
+ */
+static int
+zfs_holey_common(struct inode *ip, int cmd, loff_t *off)
+{
+       znode_t *zp = ITOZ(ip);
+       uint64_t noff = (uint64_t)*off; /* new offset */
+       uint64_t file_sz;
+       int error;
+       boolean_t hole;
+
+       file_sz = zp->z_size;
+       if (noff >= file_sz)  {
+               return (ENXIO);
+       }
+
+       if (cmd == SEEK_HOLE)
+               hole = B_TRUE;
+       else
+               hole = B_FALSE;
+
+       error = dmu_offset_next(ZTOZSB(zp)->z_os, zp->z_id, hole, &noff);
+
+       /* end of file? */
+       if ((error == ESRCH) || (noff > file_sz)) {
+               /*
+                * Handle the virtual hole at the end of file.
+                */
+               if (hole) {
+                       *off = file_sz;
+                       return (0);
+               }
+               return (ENXIO);
+       }
+
+       if (noff < *off)
+               return (error);
+       *off = noff;
+       return (error);
+}
+
+int
+zfs_holey(struct inode *ip, int cmd, loff_t *off)
+{
+       znode_t *zp = ITOZ(ip);
+       zfs_sb_t *zsb = ITOZSB(ip);
+       int error;
+
+       ZFS_ENTER(zsb);
+       ZFS_VERIFY_ZP(zp);
+
+       error = zfs_holey_common(ip, cmd, off);
+
+       ZFS_EXIT(zsb);
+       return (error);
+}
+EXPORT_SYMBOL(zfs_holey);
+#endif /* SEEK_HOLE && SEEK_DATA */
+
 #if defined(_KERNEL)
 /*
  * When a file is memory mapped, we must keep the IO data synchronized