igrab(ZTOZSB(zp)->z_ctldir);
return (ZTOZSB(zp)->z_ctldir);
}
+
/*
- * Generate a long fid which includes the root object and objset of a
- * snapshot but not the generation number. For the root object the
- * generation number is ignored when zero to avoid needing to open
- * the dataset when generating fids for the snapshot names.
+ * Generate a long fid to indicate a snapdir. We encode whether snapdir is
+ * already monunted in gen field. We do this because nfsd lookup will not
+ * trigger automount. Next time the nfsd does fh_to_dentry, we will notice
+ * this and do automount and return ESTALE to force nfsd revalidate and follow
+ * mount.
*/
static int
zfsctl_snapdir_fid(struct inode *ip, fid_t *fidp)
{
- zfs_sb_t *zsb = ITOZSB(ip);
zfid_short_t *zfid = (zfid_short_t *)fidp;
zfid_long_t *zlfid = (zfid_long_t *)fidp;
uint32_t gen = 0;
uint64_t object;
uint64_t objsetid;
int i;
+ struct dentry *dentry;
+
+ if (fidp->fid_len < LONG_FID_LEN) {
+ fidp->fid_len = LONG_FID_LEN;
+ return (SET_ERROR(ENOSPC));
+ }
- object = zsb->z_root;
+ object = ip->i_ino;
objsetid = ZFSCTL_INO_SNAPDIRS - ip->i_ino;
zfid->zf_len = LONG_FID_LEN;
+ dentry = d_obtain_alias(igrab(ip));
+ if (!IS_ERR(dentry)) {
+ gen = !!d_mountpoint(dentry);
+ dput(dentry);
+ }
+
for (i = 0; i < sizeof (zfid->zf_object); i++)
zfid->zf_object[i] = (uint8_t)(object >> (8 * i));
ZFS_ENTER(zsb);
- if (fidp->fid_len < SHORT_FID_LEN) {
- fidp->fid_len = SHORT_FID_LEN;
+ if (zfsctl_is_snapdir(ip)) {
ZFS_EXIT(zsb);
- return (SET_ERROR(ENOSPC));
+ return (zfsctl_snapdir_fid(ip, fidp));
}
- if (zfsctl_is_snapdir(ip)) {
+ if (fidp->fid_len < SHORT_FID_LEN) {
+ fidp->fid_len = SHORT_FID_LEN;
ZFS_EXIT(zsb);
- return (zfsctl_snapdir_fid(ip, fidp));
+ return (SET_ERROR(ENOSPC));
}
zfid = (zfid_short_t *)fidp;
}
/*
- * Given the objset id of the snapshot return its zfs_sb_t as zsbp.
+ * Get the snapdir inode from fid
*/
int
-zfsctl_lookup_objset(struct super_block *sb, uint64_t objsetid, zfs_sb_t **zsbp)
+zfsctl_snapdir_vget(struct super_block *sb, uint64_t objsetid, int gen,
+ struct inode **ipp)
{
- zfs_snapentry_t *se;
int error;
- spa_t *spa = ((zfs_sb_t *)(sb->s_fs_info))->z_os->os_spa;
-
- /*
- * Verify that the snapshot is mounted then lookup the mounted root
- * rather than the covered mount point. This may fail if the
- * snapshot has just been unmounted by an unrelated user space
- * process. This race cannot occur to an expired mount point
- * because we hold the zfs_snapshot_lock to prevent the race.
- */
- rw_enter(&zfs_snapshot_lock, RW_READER);
- if ((se = zfsctl_snapshot_find_by_objsetid(spa, objsetid)) != NULL) {
- zfs_sb_t *zsb;
+ struct path path;
+ char *mnt;
+ struct dentry *dentry;
- zsb = ITOZSB(se->se_root_dentry->d_inode);
- ASSERT3U(dmu_objset_id(zsb->z_os), ==, objsetid);
+ mnt = kmem_alloc(MAXPATHLEN, KM_SLEEP);
- if (time_after(jiffies, zsb->z_snap_defer_time +
- MAX(zfs_expire_snapshot * HZ / 2, HZ))) {
- zsb->z_snap_defer_time = jiffies;
- zfsctl_snapshot_unmount_cancel(se);
- zfsctl_snapshot_unmount_delay_impl(se,
- zfs_expire_snapshot);
- }
+ error = zfsctl_snapshot_path_objset(sb->s_fs_info, objsetid,
+ MAXPATHLEN, mnt);
+ if (error)
+ goto out;
- *zsbp = zsb;
- zfsctl_snapshot_rele(se);
- error = SET_ERROR(0);
- } else {
- error = SET_ERROR(ENOENT);
- }
- rw_exit(&zfs_snapshot_lock);
+ /* Trigger automount */
+ error = kern_path(mnt, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &path);
+ if (error)
+ goto out;
+ path_put(&path);
/*
- * Automount the snapshot given the objset id by constructing the
- * full mount point and performing a traversal.
+ * Get the snapdir inode. Note, we don't want to use the above
+ * path because it contains the root of the snapshot rather
+ * than the snapdir.
*/
- if (error == ENOENT) {
- struct path path;
- char *mnt;
-
- mnt = kmem_alloc(MAXPATHLEN, KM_SLEEP);
- error = zfsctl_snapshot_path_objset(sb->s_fs_info, objsetid,
- MAXPATHLEN, mnt);
- if (error) {
- kmem_free(mnt, MAXPATHLEN);
- return (SET_ERROR(error));
- }
-
- error = kern_path(mnt, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &path);
- if (error == 0) {
- *zsbp = ITOZSB(path.dentry->d_inode);
- path_put(&path);
- }
-
- kmem_free(mnt, MAXPATHLEN);
+ *ipp = ilookup(sb, ZFSCTL_INO_SNAPDIRS - objsetid);
+ if (*ipp == NULL) {
+ error = SET_ERROR(ENOENT);
+ goto out;
}
+ /* check gen, see zfsctl_snapdir_fid */
+ dentry = d_obtain_alias(igrab(*ipp));
+ if (gen != (!IS_ERR(dentry) && d_mountpoint(dentry))) {
+ iput(*ipp);
+ *ipp = NULL;
+ error = SET_ERROR(ENOENT);
+ }
+ if (!IS_ERR(dentry))
+ dput(dentry);
+out:
+ kmem_free(mnt, MAXPATHLEN);
return (error);
}
*ipp = NULL;
- ZFS_ENTER(zsb);
+ if (fidp->fid_len == SHORT_FID_LEN || fidp->fid_len == LONG_FID_LEN) {
+ zfid_short_t *zfid = (zfid_short_t *)fidp;
+
+ for (i = 0; i < sizeof (zfid->zf_object); i++)
+ object |= ((uint64_t)zfid->zf_object[i]) << (8 * i);
+ for (i = 0; i < sizeof (zfid->zf_gen); i++)
+ fid_gen |= ((uint64_t)zfid->zf_gen[i]) << (8 * i);
+ } else {
+ return (SET_ERROR(EINVAL));
+ }
+
+ /* LONG_FID_LEN means snapdirs */
if (fidp->fid_len == LONG_FID_LEN) {
zfid_long_t *zlfid = (zfid_long_t *)fidp;
uint64_t objsetid = 0;
for (i = 0; i < sizeof (zlfid->zf_setgen); i++)
setgen |= ((uint64_t)zlfid->zf_setgen[i]) << (8 * i);
- ZFS_EXIT(zsb);
+ if (objsetid != ZFSCTL_INO_SNAPDIRS - object) {
+ dprintf("snapdir fid: objsetid (%llu) != "
+ "ZFSCTL_INO_SNAPDIRS (%llu) - object (%llu)\n",
+ objsetid, ZFSCTL_INO_SNAPDIRS, object);
- err = zfsctl_lookup_objset(sb, objsetid, &zsb);
- if (err)
return (SET_ERROR(EINVAL));
+ }
- ZFS_ENTER(zsb);
- }
-
- if (fidp->fid_len == SHORT_FID_LEN || fidp->fid_len == LONG_FID_LEN) {
- zfid_short_t *zfid = (zfid_short_t *)fidp;
-
- for (i = 0; i < sizeof (zfid->zf_object); i++)
- object |= ((uint64_t)zfid->zf_object[i]) << (8 * i);
+ if (fid_gen > 1 || setgen != 0) {
+ dprintf("snapdir fid: fid_gen (%llu) and setgen "
+ "(%llu)\n", fid_gen, setgen);
+ return (SET_ERROR(EINVAL));
+ }
- for (i = 0; i < sizeof (zfid->zf_gen); i++)
- fid_gen |= ((uint64_t)zfid->zf_gen[i]) << (8 * i);
- } else {
- ZFS_EXIT(zsb);
- return (SET_ERROR(EINVAL));
+ return (zfsctl_snapdir_vget(sb, objsetid, fid_gen, ipp));
}
+ ZFS_ENTER(zsb);
/* A zero fid_gen means we are in the .zfs control directories */
if (fid_gen == 0 &&
(object == ZFSCTL_INO_ROOT || object == ZFSCTL_INO_SNAPDIR)) {
projects / zfs / commitdiff