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zfs_ctldir.c
1317 lines (1136 loc) · 34.3 KB
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zfs_ctldir.c
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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or https://opensource.org/licenses/CDDL-1.0.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (C) 2011 Lawrence Livermore National Security, LLC.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* LLNL-CODE-403049.
* Rewritten for Linux by:
* Rohan Puri <rohan.puri15@gmail.com>
* Brian Behlendorf <behlendorf1@llnl.gov>
* Copyright (c) 2013 by Delphix. All rights reserved.
* Copyright 2015, OmniTI Computer Consulting, Inc. All rights reserved.
* Copyright (c) 2018 George Melikov. All Rights Reserved.
* Copyright (c) 2019 Datto, Inc. All rights reserved.
* Copyright (c) 2020 The MathWorks, Inc. All rights reserved.
*/
/*
* ZFS control directory (a.k.a. ".zfs")
*
* This directory provides a common location for all ZFS meta-objects.
* Currently, this is only the 'snapshot' and 'shares' directory, but this may
* expand in the future. The elements are built dynamically, as the hierarchy
* does not actually exist on disk.
*
* For 'snapshot', we don't want to have all snapshots always mounted, because
* this would take up a huge amount of space in /etc/mnttab. We have three
* types of objects:
*
* ctldir ------> snapshotdir -------> snapshot
* |
* |
* V
* mounted fs
*
* The 'snapshot' node contains just enough information to lookup '..' and act
* as a mountpoint for the snapshot. Whenever we lookup a specific snapshot, we
* perform an automount of the underlying filesystem and return the
* corresponding inode.
*
* All mounts are handled automatically by an user mode helper which invokes
* the mount procedure. Unmounts are handled by allowing the mount
* point to expire so the kernel may automatically unmount it.
*
* The '.zfs', '.zfs/snapshot', and all directories created under
* '.zfs/snapshot' (ie: '.zfs/snapshot/<snapname>') all share the same
* zfsvfs_t as the head filesystem (what '.zfs' lives under).
*
* File systems mounted on top of the '.zfs/snapshot/<snapname>' paths
* (ie: snapshots) are complete ZFS filesystems and have their own unique
* zfsvfs_t. However, the fsid reported by these mounts will be the same
* as that used by the parent zfsvfs_t to make NFS happy.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/sysmacros.h>
#include <sys/pathname.h>
#include <sys/vfs.h>
#include <sys/zfs_ctldir.h>
#include <sys/zfs_ioctl.h>
#include <sys/zfs_vfsops.h>
#include <sys/zfs_vnops.h>
#include <sys/stat.h>
#include <sys/dmu.h>
#include <sys/dmu_objset.h>
#include <sys/dsl_destroy.h>
#include <sys/dsl_deleg.h>
#include <sys/zpl.h>
#include <sys/mntent.h>
#include "zfs_namecheck.h"
/*
* Two AVL trees are maintained which contain all currently automounted
* snapshots. Every automounted snapshots maps to a single zfs_snapentry_t
* entry which MUST:
*
* - be attached to both trees, and
* - be unique, no duplicate entries are allowed.
*
* The zfs_snapshots_by_name tree is indexed by the full dataset name
* while the zfs_snapshots_by_objsetid tree is indexed by the unique
* objsetid. This allows for fast lookups either by name or objsetid.
*/
static avl_tree_t zfs_snapshots_by_name;
static avl_tree_t zfs_snapshots_by_objsetid;
static krwlock_t zfs_snapshot_lock;
/*
* Control Directory Tunables (.zfs)
*/
int zfs_expire_snapshot = ZFSCTL_EXPIRE_SNAPSHOT;
static int zfs_admin_snapshot = 0;
typedef struct {
char *se_name; /* full snapshot name */
char *se_path; /* full mount path */
spa_t *se_spa; /* pool spa */
uint64_t se_objsetid; /* snapshot objset id */
struct dentry *se_root_dentry; /* snapshot root dentry */
krwlock_t se_taskqid_lock; /* scheduled unmount taskqid lock */
taskqid_t se_taskqid; /* scheduled unmount taskqid */
avl_node_t se_node_name; /* zfs_snapshots_by_name link */
avl_node_t se_node_objsetid; /* zfs_snapshots_by_objsetid link */
zfs_refcount_t se_refcount; /* reference count */
} zfs_snapentry_t;
static void zfsctl_snapshot_unmount_delay_impl(zfs_snapentry_t *se, int delay);
/*
* Allocate a new zfs_snapentry_t being careful to make a copy of the
* the snapshot name and provided mount point. No reference is taken.
*/
static zfs_snapentry_t *
zfsctl_snapshot_alloc(const char *full_name, const char *full_path, spa_t *spa,
uint64_t objsetid, struct dentry *root_dentry)
{
zfs_snapentry_t *se;
se = kmem_zalloc(sizeof (zfs_snapentry_t), KM_SLEEP);
se->se_name = kmem_strdup(full_name);
se->se_path = kmem_strdup(full_path);
se->se_spa = spa;
se->se_objsetid = objsetid;
se->se_root_dentry = root_dentry;
se->se_taskqid = TASKQID_INVALID;
rw_init(&se->se_taskqid_lock, NULL, RW_DEFAULT, NULL);
zfs_refcount_create(&se->se_refcount);
return (se);
}
/*
* Free a zfs_snapentry_t the caller must ensure there are no active
* references.
*/
static void
zfsctl_snapshot_free(zfs_snapentry_t *se)
{
zfs_refcount_destroy(&se->se_refcount);
kmem_strfree(se->se_name);
kmem_strfree(se->se_path);
rw_destroy(&se->se_taskqid_lock);
kmem_free(se, sizeof (zfs_snapentry_t));
}
/*
* Hold a reference on the zfs_snapentry_t.
*/
static void
zfsctl_snapshot_hold(zfs_snapentry_t *se)
{
zfs_refcount_add(&se->se_refcount, NULL);
}
/*
* Release a reference on the zfs_snapentry_t. When the number of
* references drops to zero the structure will be freed.
*/
static void
zfsctl_snapshot_rele(zfs_snapentry_t *se)
{
if (zfs_refcount_remove(&se->se_refcount, NULL) == 0)
zfsctl_snapshot_free(se);
}
/*
* Add a zfs_snapentry_t to both the zfs_snapshots_by_name and
* zfs_snapshots_by_objsetid trees. While the zfs_snapentry_t is part
* of the trees a reference is held.
*/
static void
zfsctl_snapshot_add(zfs_snapentry_t *se)
{
ASSERT(RW_WRITE_HELD(&zfs_snapshot_lock));
zfsctl_snapshot_hold(se);
avl_add(&zfs_snapshots_by_name, se);
avl_add(&zfs_snapshots_by_objsetid, se);
}
/*
* Remove a zfs_snapentry_t from both the zfs_snapshots_by_name and
* zfs_snapshots_by_objsetid trees. Upon removal a reference is dropped,
* this can result in the structure being freed if that was the last
* remaining reference.
*/
static void
zfsctl_snapshot_remove(zfs_snapentry_t *se)
{
ASSERT(RW_WRITE_HELD(&zfs_snapshot_lock));
avl_remove(&zfs_snapshots_by_name, se);
avl_remove(&zfs_snapshots_by_objsetid, se);
zfsctl_snapshot_rele(se);
}
/*
* Snapshot name comparison function for the zfs_snapshots_by_name.
*/
static int
snapentry_compare_by_name(const void *a, const void *b)
{
const zfs_snapentry_t *se_a = a;
const zfs_snapentry_t *se_b = b;
int ret;
ret = strcmp(se_a->se_name, se_b->se_name);
if (ret < 0)
return (-1);
else if (ret > 0)
return (1);
else
return (0);
}
/*
* Snapshot name comparison function for the zfs_snapshots_by_objsetid.
*/
static int
snapentry_compare_by_objsetid(const void *a, const void *b)
{
const zfs_snapentry_t *se_a = a;
const zfs_snapentry_t *se_b = b;
if (se_a->se_spa != se_b->se_spa)
return ((ulong_t)se_a->se_spa < (ulong_t)se_b->se_spa ? -1 : 1);
if (se_a->se_objsetid < se_b->se_objsetid)
return (-1);
else if (se_a->se_objsetid > se_b->se_objsetid)
return (1);
else
return (0);
}
/*
* Find a zfs_snapentry_t in zfs_snapshots_by_name. If the snapname
* is found a pointer to the zfs_snapentry_t is returned and a reference
* taken on the structure. The caller is responsible for dropping the
* reference with zfsctl_snapshot_rele(). If the snapname is not found
* NULL will be returned.
*/
static zfs_snapentry_t *
zfsctl_snapshot_find_by_name(const char *snapname)
{
zfs_snapentry_t *se, search;
ASSERT(RW_LOCK_HELD(&zfs_snapshot_lock));
search.se_name = (char *)snapname;
se = avl_find(&zfs_snapshots_by_name, &search, NULL);
if (se)
zfsctl_snapshot_hold(se);
return (se);
}
/*
* Find a zfs_snapentry_t in zfs_snapshots_by_objsetid given the objset id
* rather than the snapname. In all other respects it behaves the same
* as zfsctl_snapshot_find_by_name().
*/
static zfs_snapentry_t *
zfsctl_snapshot_find_by_objsetid(spa_t *spa, uint64_t objsetid)
{
zfs_snapentry_t *se, search;
ASSERT(RW_LOCK_HELD(&zfs_snapshot_lock));
search.se_spa = spa;
search.se_objsetid = objsetid;
se = avl_find(&zfs_snapshots_by_objsetid, &search, NULL);
if (se)
zfsctl_snapshot_hold(se);
return (se);
}
/*
* Rename a zfs_snapentry_t in the zfs_snapshots_by_name. The structure is
* removed, renamed, and added back to the new correct location in the tree.
*/
static int
zfsctl_snapshot_rename(const char *old_snapname, const char *new_snapname)
{
zfs_snapentry_t *se;
ASSERT(RW_WRITE_HELD(&zfs_snapshot_lock));
se = zfsctl_snapshot_find_by_name(old_snapname);
if (se == NULL)
return (SET_ERROR(ENOENT));
zfsctl_snapshot_remove(se);
kmem_strfree(se->se_name);
se->se_name = kmem_strdup(new_snapname);
zfsctl_snapshot_add(se);
zfsctl_snapshot_rele(se);
return (0);
}
/*
* Delayed task responsible for unmounting an expired automounted snapshot.
*/
static void
snapentry_expire(void *data)
{
zfs_snapentry_t *se = (zfs_snapentry_t *)data;
spa_t *spa = se->se_spa;
uint64_t objsetid = se->se_objsetid;
if (zfs_expire_snapshot <= 0) {
zfsctl_snapshot_rele(se);
return;
}
rw_enter(&se->se_taskqid_lock, RW_WRITER);
se->se_taskqid = TASKQID_INVALID;
rw_exit(&se->se_taskqid_lock);
(void) zfsctl_snapshot_unmount(se->se_name, MNT_EXPIRE);
zfsctl_snapshot_rele(se);
/*
* Reschedule the unmount if the zfs_snapentry_t wasn't removed.
* This can occur when the snapshot is busy.
*/
rw_enter(&zfs_snapshot_lock, RW_READER);
if ((se = zfsctl_snapshot_find_by_objsetid(spa, objsetid)) != NULL) {
zfsctl_snapshot_unmount_delay_impl(se, zfs_expire_snapshot);
zfsctl_snapshot_rele(se);
}
rw_exit(&zfs_snapshot_lock);
}
/*
* Cancel an automatic unmount of a snapname. This callback is responsible
* for dropping the reference on the zfs_snapentry_t which was taken when
* during dispatch.
*/
static void
zfsctl_snapshot_unmount_cancel(zfs_snapentry_t *se)
{
int err = 0;
rw_enter(&se->se_taskqid_lock, RW_WRITER);
err = taskq_cancel_id(system_delay_taskq, se->se_taskqid);
/*
* if we get ENOENT, the taskq couldn't be found to be
* canceled, so we can just mark it as invalid because
* it's already gone. If we got EBUSY, then we already
* blocked until it was gone _anyway_, so we don't care.
*/
se->se_taskqid = TASKQID_INVALID;
rw_exit(&se->se_taskqid_lock);
if (err == 0) {
zfsctl_snapshot_rele(se);
}
}
/*
* Dispatch the unmount task for delayed handling with a hold protecting it.
*/
static void
zfsctl_snapshot_unmount_delay_impl(zfs_snapentry_t *se, int delay)
{
if (delay <= 0)
return;
zfsctl_snapshot_hold(se);
rw_enter(&se->se_taskqid_lock, RW_WRITER);
/*
* If this condition happens, we managed to:
* - dispatch once
* - want to dispatch _again_ before it returned
*
* So let's just return - if that task fails at unmounting,
* we'll eventually dispatch again, and if it succeeds,
* no problem.
*/
if (se->se_taskqid != TASKQID_INVALID) {
rw_exit(&se->se_taskqid_lock);
zfsctl_snapshot_rele(se);
return;
}
se->se_taskqid = taskq_dispatch_delay(system_delay_taskq,
snapentry_expire, se, TQ_SLEEP, ddi_get_lbolt() + delay * HZ);
rw_exit(&se->se_taskqid_lock);
}
/*
* Schedule an automatic unmount of objset id to occur in delay seconds from
* now. Any previous delayed unmount will be cancelled in favor of the
* updated deadline. A reference is taken by zfsctl_snapshot_find_by_name()
* and held until the outstanding task is handled or cancelled.
*/
int
zfsctl_snapshot_unmount_delay(spa_t *spa, uint64_t objsetid, int delay)
{
zfs_snapentry_t *se;
int error = ENOENT;
rw_enter(&zfs_snapshot_lock, RW_READER);
if ((se = zfsctl_snapshot_find_by_objsetid(spa, objsetid)) != NULL) {
zfsctl_snapshot_unmount_cancel(se);
zfsctl_snapshot_unmount_delay_impl(se, delay);
zfsctl_snapshot_rele(se);
error = 0;
}
rw_exit(&zfs_snapshot_lock);
return (error);
}
/*
* Check if snapname is currently mounted. Returned non-zero when mounted
* and zero when unmounted.
*/
static boolean_t
zfsctl_snapshot_ismounted(const char *snapname)
{
zfs_snapentry_t *se;
boolean_t ismounted = B_FALSE;
rw_enter(&zfs_snapshot_lock, RW_READER);
if ((se = zfsctl_snapshot_find_by_name(snapname)) != NULL) {
zfsctl_snapshot_rele(se);
ismounted = B_TRUE;
}
rw_exit(&zfs_snapshot_lock);
return (ismounted);
}
/*
* Check if the given inode is a part of the virtual .zfs directory.
*/
boolean_t
zfsctl_is_node(struct inode *ip)
{
return (ITOZ(ip)->z_is_ctldir);
}
/*
* Check if the given inode is a .zfs/snapshots/snapname directory.
*/
boolean_t
zfsctl_is_snapdir(struct inode *ip)
{
return (zfsctl_is_node(ip) && (ip->i_ino <= ZFSCTL_INO_SNAPDIRS));
}
/*
* Allocate a new inode with the passed id and ops.
*/
static struct inode *
zfsctl_inode_alloc(zfsvfs_t *zfsvfs, uint64_t id,
const struct file_operations *fops, const struct inode_operations *ops,
uint64_t creation)
{
struct inode *ip;
znode_t *zp;
inode_timespec_t now = {.tv_sec = creation};
ip = new_inode(zfsvfs->z_sb);
if (ip == NULL)
return (NULL);
if (!creation)
now = current_time(ip);
zp = ITOZ(ip);
ASSERT3P(zp->z_dirlocks, ==, NULL);
ASSERT3P(zp->z_acl_cached, ==, NULL);
ASSERT3P(zp->z_xattr_cached, ==, NULL);
zp->z_id = id;
zp->z_unlinked = B_FALSE;
zp->z_atime_dirty = B_FALSE;
zp->z_zn_prefetch = B_FALSE;
zp->z_is_sa = B_FALSE;
#if !defined(HAVE_FILEMAP_RANGE_HAS_PAGE)
zp->z_is_mapped = B_FALSE;
#endif
zp->z_is_ctldir = B_TRUE;
zp->z_sa_hdl = NULL;
zp->z_blksz = 0;
zp->z_seq = 0;
zp->z_mapcnt = 0;
zp->z_size = 0;
zp->z_pflags = 0;
zp->z_mode = 0;
zp->z_sync_cnt = 0;
zp->z_sync_writes_cnt = 0;
zp->z_async_writes_cnt = 0;
ip->i_generation = 0;
ip->i_ino = id;
ip->i_mode = (S_IFDIR | S_IRWXUGO);
ip->i_uid = SUID_TO_KUID(0);
ip->i_gid = SGID_TO_KGID(0);
ip->i_blkbits = SPA_MINBLOCKSHIFT;
ip->i_atime = now;
ip->i_mtime = now;
zpl_inode_set_ctime_to_ts(ip, now);
ip->i_fop = fops;
ip->i_op = ops;
#if defined(IOP_XATTR)
ip->i_opflags &= ~IOP_XATTR;
#endif
if (insert_inode_locked(ip)) {
unlock_new_inode(ip);
iput(ip);
return (NULL);
}
mutex_enter(&zfsvfs->z_znodes_lock);
list_insert_tail(&zfsvfs->z_all_znodes, zp);
membar_producer();
mutex_exit(&zfsvfs->z_znodes_lock);
unlock_new_inode(ip);
return (ip);
}
/*
* Lookup the inode with given id, it will be allocated if needed.
*/
static struct inode *
zfsctl_inode_lookup(zfsvfs_t *zfsvfs, uint64_t id,
const struct file_operations *fops, const struct inode_operations *ops)
{
struct inode *ip = NULL;
uint64_t creation = 0;
dsl_dataset_t *snap_ds;
dsl_pool_t *pool;
while (ip == NULL) {
ip = ilookup(zfsvfs->z_sb, (unsigned long)id);
if (ip)
break;
if (id <= ZFSCTL_INO_SNAPDIRS && !creation) {
pool = dmu_objset_pool(zfsvfs->z_os);
dsl_pool_config_enter(pool, FTAG);
if (!dsl_dataset_hold_obj(pool,
ZFSCTL_INO_SNAPDIRS - id, FTAG, &snap_ds)) {
creation = dsl_get_creation(snap_ds);
dsl_dataset_rele(snap_ds, FTAG);
}
dsl_pool_config_exit(pool, FTAG);
}
/* May fail due to concurrent zfsctl_inode_alloc() */
ip = zfsctl_inode_alloc(zfsvfs, id, fops, ops, creation);
}
return (ip);
}
/*
* Create the '.zfs' directory. This directory is cached as part of the VFS
* structure. This results in a hold on the zfsvfs_t. The code in zfs_umount()
* therefore checks against a vfs_count of 2 instead of 1. This reference
* is removed when the ctldir is destroyed in the unmount. All other entities
* under the '.zfs' directory are created dynamically as needed.
*
* Because the dynamically created '.zfs' directory entries assume the use
* of 64-bit inode numbers this support must be disabled on 32-bit systems.
*/
int
zfsctl_create(zfsvfs_t *zfsvfs)
{
ASSERT(zfsvfs->z_ctldir == NULL);
zfsvfs->z_ctldir = zfsctl_inode_alloc(zfsvfs, ZFSCTL_INO_ROOT,
&zpl_fops_root, &zpl_ops_root, 0);
if (zfsvfs->z_ctldir == NULL)
return (SET_ERROR(ENOENT));
return (0);
}
/*
* Destroy the '.zfs' directory or remove a snapshot from zfs_snapshots_by_name.
* Only called when the filesystem is unmounted.
*/
void
zfsctl_destroy(zfsvfs_t *zfsvfs)
{
if (zfsvfs->z_issnap) {
zfs_snapentry_t *se;
spa_t *spa = zfsvfs->z_os->os_spa;
uint64_t objsetid = dmu_objset_id(zfsvfs->z_os);
rw_enter(&zfs_snapshot_lock, RW_WRITER);
se = zfsctl_snapshot_find_by_objsetid(spa, objsetid);
if (se != NULL)
zfsctl_snapshot_remove(se);
rw_exit(&zfs_snapshot_lock);
if (se != NULL) {
zfsctl_snapshot_unmount_cancel(se);
zfsctl_snapshot_rele(se);
}
} else if (zfsvfs->z_ctldir) {
iput(zfsvfs->z_ctldir);
zfsvfs->z_ctldir = NULL;
}
}
/*
* Given a root znode, retrieve the associated .zfs directory.
* Add a hold to the vnode and return it.
*/
struct inode *
zfsctl_root(znode_t *zp)
{
ASSERT(zfs_has_ctldir(zp));
/* Must have an existing ref, so igrab() cannot return NULL */
VERIFY3P(igrab(ZTOZSB(zp)->z_ctldir), !=, NULL);
return (ZTOZSB(zp)->z_ctldir);
}
/*
* Generate a long fid to indicate a snapdir. We encode whether snapdir is
* already mounted 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)
{
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 = 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));
for (i = 0; i < sizeof (zfid->zf_gen); i++)
zfid->zf_gen[i] = (uint8_t)(gen >> (8 * i));
for (i = 0; i < sizeof (zlfid->zf_setid); i++)
zlfid->zf_setid[i] = (uint8_t)(objsetid >> (8 * i));
for (i = 0; i < sizeof (zlfid->zf_setgen); i++)
zlfid->zf_setgen[i] = 0;
return (0);
}
/*
* Generate an appropriate fid for an entry in the .zfs directory.
*/
int
zfsctl_fid(struct inode *ip, fid_t *fidp)
{
znode_t *zp = ITOZ(ip);
zfsvfs_t *zfsvfs = ITOZSB(ip);
uint64_t object = zp->z_id;
zfid_short_t *zfid;
int i;
int error;
if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
return (error);
if (zfsctl_is_snapdir(ip)) {
zfs_exit(zfsvfs, FTAG);
return (zfsctl_snapdir_fid(ip, fidp));
}
if (fidp->fid_len < SHORT_FID_LEN) {
fidp->fid_len = SHORT_FID_LEN;
zfs_exit(zfsvfs, FTAG);
return (SET_ERROR(ENOSPC));
}
zfid = (zfid_short_t *)fidp;
zfid->zf_len = SHORT_FID_LEN;
for (i = 0; i < sizeof (zfid->zf_object); i++)
zfid->zf_object[i] = (uint8_t)(object >> (8 * i));
/* .zfs znodes always have a generation number of 0 */
for (i = 0; i < sizeof (zfid->zf_gen); i++)
zfid->zf_gen[i] = 0;
zfs_exit(zfsvfs, FTAG);
return (0);
}
/*
* Construct a full dataset name in full_name: "pool/dataset@snap_name"
*/
static int
zfsctl_snapshot_name(zfsvfs_t *zfsvfs, const char *snap_name, int len,
char *full_name)
{
objset_t *os = zfsvfs->z_os;
if (zfs_component_namecheck(snap_name, NULL, NULL) != 0)
return (SET_ERROR(EILSEQ));
dmu_objset_name(os, full_name);
if ((strlen(full_name) + 1 + strlen(snap_name)) >= len)
return (SET_ERROR(ENAMETOOLONG));
(void) strcat(full_name, "@");
(void) strcat(full_name, snap_name);
return (0);
}
/*
* Returns full path in full_path: "/pool/dataset/.zfs/snapshot/snap_name/"
*/
static int
zfsctl_snapshot_path_objset(zfsvfs_t *zfsvfs, uint64_t objsetid,
int path_len, char *full_path)
{
objset_t *os = zfsvfs->z_os;
fstrans_cookie_t cookie;
char *snapname;
boolean_t case_conflict;
uint64_t id, pos = 0;
int error = 0;
if (zfsvfs->z_vfs->vfs_mntpoint == NULL)
return (SET_ERROR(ENOENT));
cookie = spl_fstrans_mark();
snapname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
while (error == 0) {
dsl_pool_config_enter(dmu_objset_pool(os), FTAG);
error = dmu_snapshot_list_next(zfsvfs->z_os,
ZFS_MAX_DATASET_NAME_LEN, snapname, &id, &pos,
&case_conflict);
dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
if (error)
goto out;
if (id == objsetid)
break;
}
snprintf(full_path, path_len, "%s/.zfs/snapshot/%s",
zfsvfs->z_vfs->vfs_mntpoint, snapname);
out:
kmem_free(snapname, ZFS_MAX_DATASET_NAME_LEN);
spl_fstrans_unmark(cookie);
return (error);
}
/*
* Special case the handling of "..".
*/
int
zfsctl_root_lookup(struct inode *dip, const char *name, struct inode **ipp,
int flags, cred_t *cr, int *direntflags, pathname_t *realpnp)
{
zfsvfs_t *zfsvfs = ITOZSB(dip);
int error = 0;
if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
return (error);
if (strcmp(name, "..") == 0) {
*ipp = dip->i_sb->s_root->d_inode;
} else if (strcmp(name, ZFS_SNAPDIR_NAME) == 0) {
*ipp = zfsctl_inode_lookup(zfsvfs, ZFSCTL_INO_SNAPDIR,
&zpl_fops_snapdir, &zpl_ops_snapdir);
} else if (strcmp(name, ZFS_SHAREDIR_NAME) == 0) {
*ipp = zfsctl_inode_lookup(zfsvfs, ZFSCTL_INO_SHARES,
&zpl_fops_shares, &zpl_ops_shares);
} else {
*ipp = NULL;
}
if (*ipp == NULL)
error = SET_ERROR(ENOENT);
zfs_exit(zfsvfs, FTAG);
return (error);
}
/*
* Lookup entry point for the 'snapshot' directory. Try to open the
* snapshot if it exist, creating the pseudo filesystem inode as necessary.
*/
int
zfsctl_snapdir_lookup(struct inode *dip, const char *name, struct inode **ipp,
int flags, cred_t *cr, int *direntflags, pathname_t *realpnp)
{
zfsvfs_t *zfsvfs = ITOZSB(dip);
uint64_t id;
int error;
if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
return (error);
error = dmu_snapshot_lookup(zfsvfs->z_os, name, &id);
if (error) {
zfs_exit(zfsvfs, FTAG);
return (error);
}
*ipp = zfsctl_inode_lookup(zfsvfs, ZFSCTL_INO_SNAPDIRS - id,
&simple_dir_operations, &simple_dir_inode_operations);
if (*ipp == NULL)
error = SET_ERROR(ENOENT);
zfs_exit(zfsvfs, FTAG);
return (error);
}
/*
* Renaming a directory under '.zfs/snapshot' will automatically trigger
* a rename of the snapshot to the new given name. The rename is confined
* to the '.zfs/snapshot' directory snapshots cannot be moved elsewhere.
*/
int
zfsctl_snapdir_rename(struct inode *sdip, const char *snm,
struct inode *tdip, const char *tnm, cred_t *cr, int flags)
{
zfsvfs_t *zfsvfs = ITOZSB(sdip);
char *to, *from, *real, *fsname;
int error;
if (!zfs_admin_snapshot)
return (SET_ERROR(EACCES));
if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
return (error);
to = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
from = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
real = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
fsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
error = dmu_snapshot_realname(zfsvfs->z_os, snm, real,
ZFS_MAX_DATASET_NAME_LEN, NULL);
if (error == 0) {
snm = real;
} else if (error != ENOTSUP) {
goto out;
}
}
dmu_objset_name(zfsvfs->z_os, fsname);
error = zfsctl_snapshot_name(ITOZSB(sdip), snm,
ZFS_MAX_DATASET_NAME_LEN, from);
if (error == 0)
error = zfsctl_snapshot_name(ITOZSB(tdip), tnm,
ZFS_MAX_DATASET_NAME_LEN, to);
if (error == 0)
error = zfs_secpolicy_rename_perms(from, to, cr);
if (error != 0)
goto out;
/*
* Cannot move snapshots out of the snapdir.
*/
if (sdip != tdip) {
error = SET_ERROR(EINVAL);
goto out;
}
/*
* No-op when names are identical.
*/
if (strcmp(snm, tnm) == 0) {
error = 0;
goto out;
}
rw_enter(&zfs_snapshot_lock, RW_WRITER);
error = dsl_dataset_rename_snapshot(fsname, snm, tnm, B_FALSE);
if (error == 0)
(void) zfsctl_snapshot_rename(snm, tnm);
rw_exit(&zfs_snapshot_lock);
out:
kmem_free(from, ZFS_MAX_DATASET_NAME_LEN);
kmem_free(to, ZFS_MAX_DATASET_NAME_LEN);
kmem_free(real, ZFS_MAX_DATASET_NAME_LEN);
kmem_free(fsname, ZFS_MAX_DATASET_NAME_LEN);
zfs_exit(zfsvfs, FTAG);
return (error);
}
/*
* Removing a directory under '.zfs/snapshot' will automatically trigger
* the removal of the snapshot with the given name.
*/
int
zfsctl_snapdir_remove(struct inode *dip, const char *name, cred_t *cr,
int flags)
{
zfsvfs_t *zfsvfs = ITOZSB(dip);
char *snapname, *real;
int error;
if (!zfs_admin_snapshot)
return (SET_ERROR(EACCES));
if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
return (error);
snapname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
real = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
error = dmu_snapshot_realname(zfsvfs->z_os, name, real,
ZFS_MAX_DATASET_NAME_LEN, NULL);
if (error == 0) {
name = real;
} else if (error != ENOTSUP) {
goto out;
}
}
error = zfsctl_snapshot_name(ITOZSB(dip), name,
ZFS_MAX_DATASET_NAME_LEN, snapname);
if (error == 0)
error = zfs_secpolicy_destroy_perms(snapname, cr);
if (error != 0)
goto out;
error = zfsctl_snapshot_unmount(snapname, MNT_FORCE);
if ((error == 0) || (error == ENOENT))
error = dsl_destroy_snapshot(snapname, B_FALSE);
out:
kmem_free(snapname, ZFS_MAX_DATASET_NAME_LEN);
kmem_free(real, ZFS_MAX_DATASET_NAME_LEN);
zfs_exit(zfsvfs, FTAG);
return (error);
}
/*
* Creating a directory under '.zfs/snapshot' will automatically trigger
* the creation of a new snapshot with the given name.
*/
int
zfsctl_snapdir_mkdir(struct inode *dip, const char *dirname, vattr_t *vap,
struct inode **ipp, cred_t *cr, int flags)