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 38f04e5..3c3e8db 100644 (file)
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012 by Delphix. All rights reserved.
  */
 
 /* Portions Copyright 2007 Jeremy Teo */
@@ -239,6 +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
@@ -1523,7 +1586,7 @@ top:
            &xattr_obj, sizeof (xattr_obj));
        if (error == 0 && xattr_obj) {
                error = zfs_zget(zsb, xattr_obj, &xzp);
-               ASSERT3U(error, ==, 0);
+               ASSERT0(error);
                dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);
                dmu_tx_hold_sa(tx, xzp->z_sa_hdl, B_FALSE);
        }
@@ -2070,12 +2133,16 @@ out:
 }
 EXPORT_SYMBOL(zfs_readdir);
 
+ulong_t zfs_fsync_sync_cnt = 4;
+
 int
 zfs_fsync(struct inode *ip, int syncflag, cred_t *cr)
 {
        znode_t *zp = ITOZ(ip);
        zfs_sb_t *zsb = ITOZSB(ip);
 
+       (void) tsd_set(zfs_fsyncer_key, (void *)zfs_fsync_sync_cnt);
+
        if (zsb->z_os->os_sync != ZFS_SYNC_DISABLED) {
                ZFS_ENTER(zsb);
                ZFS_VERIFY_ZP(zp);
@@ -2833,7 +2900,7 @@ top:
                zp->z_mode = new_mode;
                ASSERT3P(aclp, !=, NULL);
                err = zfs_aclset_common(zp, aclp, cr, tx);
-               ASSERT3U(err, ==, 0);
+               ASSERT0(err);
                if (zp->z_acl_cached)
                        zfs_acl_free(zp->z_acl_cached);
                zp->z_acl_cached = aclp;
@@ -3342,7 +3409,7 @@ top:
 
                        error = sa_update(szp->z_sa_hdl, SA_ZPL_FLAGS(zsb),
                            (void *)&szp->z_pflags, sizeof (uint64_t), tx);
-                       ASSERT3U(error, ==, 0);
+                       ASSERT0(error);
 
                        error = zfs_link_destroy(sdl, szp, tx, ZRENAMING, NULL);
                        if (error == 0) {