4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
23 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright (C) 2011 Lawrence Livermore National Security, LLC.
25 * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
27 * Rewritten for Linux by:
28 * Rohan Puri <rohan.puri15@gmail.com>
29 * Brian Behlendorf <behlendorf1@llnl.gov>
33 * ZFS control directory (a.k.a. ".zfs")
35 * This directory provides a common location for all ZFS meta-objects.
36 * Currently, this is only the 'snapshot' and 'shares' directory, but this may
37 * expand in the future. The elements are built dynamically, as the hierarchy
38 * does not actually exist on disk.
40 * For 'snapshot', we don't want to have all snapshots always mounted, because
41 * this would take up a huge amount of space in /etc/mnttab. We have three
44 * ctldir ------> snapshotdir -------> snapshot
50 * The 'snapshot' node contains just enough information to lookup '..' and act
51 * as a mountpoint for the snapshot. Whenever we lookup a specific snapshot, we
52 * perform an automount of the underlying filesystem and return the
53 * corresponding inode.
55 * All mounts are handled automatically by an user mode helper which invokes
56 * the mount mount procedure. Unmounts are handled by allowing the mount
57 * point to expire so the kernel may automatically unmount it.
59 * The '.zfs', '.zfs/snapshot', and all directories created under
60 * '.zfs/snapshot' (ie: '.zfs/snapshot/<snapname>') all share the same
61 * share the same zfs_sb_t as the head filesystem (what '.zfs' lives under).
63 * File systems mounted on top of the '.zfs/snapshot/<snapname>' paths
64 * (ie: snapshots) are complete ZFS filesystems and have their own unique
65 * zfs_sb_t. However, the fsid reported by these mounts will be the same
66 * as that used by the parent zfs_sb_t to make NFS happy.
69 #include <sys/types.h>
70 #include <sys/param.h>
72 #include <sys/systm.h>
73 #include <sys/sysmacros.h>
74 #include <sys/pathname.h>
76 #include <sys/vfs_opreg.h>
77 #include <sys/zfs_ctldir.h>
78 #include <sys/zfs_ioctl.h>
79 #include <sys/zfs_vfsops.h>
80 #include <sys/zfs_vnops.h>
83 #include <sys/dsl_deleg.h>
84 #include <sys/mount.h>
86 #include "zfs_namecheck.h"
89 * Control Directory Tunables (.zfs)
91 int zfs_expire_snapshot
= ZFSCTL_EXPIRE_SNAPSHOT
;
94 * Dedicated task queue for unmounting snapshots.
96 static taskq_t
*zfs_expire_taskq
;
98 static zfs_snapentry_t
*
99 zfsctl_sep_alloc(void)
101 return kmem_zalloc(sizeof (zfs_snapentry_t
), KM_SLEEP
);
105 zfsctl_sep_free(zfs_snapentry_t
*sep
)
107 kmem_free(sep
->se_name
, MAXNAMELEN
);
108 kmem_free(sep
->se_path
, PATH_MAX
);
109 kmem_free(sep
, sizeof (zfs_snapentry_t
));
113 * Attempt to expire an automounted snapshot, unmounts are attempted every
114 * 'zfs_expire_snapshot' seconds until they succeed. The work request is
115 * responsible for rescheduling itself and freeing the zfs_expire_snapshot_t.
118 zfsctl_expire_snapshot(void *data
)
120 zfs_snapentry_t
*sep
= (zfs_snapentry_t
*)data
;
121 zfs_sb_t
*zsb
= ITOZSB(sep
->se_inode
);
124 error
= zfsctl_unmount_snapshot(zsb
, sep
->se_name
, MNT_EXPIRE
);
126 sep
->se_taskqid
= taskq_dispatch_delay(zfs_expire_taskq
,
127 zfsctl_expire_snapshot
, sep
, TQ_SLEEP
,
128 ddi_get_lbolt() + zfs_expire_snapshot
* HZ
);
132 snapentry_compare(const void *a
, const void *b
)
134 const zfs_snapentry_t
*sa
= a
;
135 const zfs_snapentry_t
*sb
= b
;
136 int ret
= strcmp(sa
->se_name
, sb
->se_name
);
147 zfsctl_is_node(struct inode
*ip
)
149 return (ITOZ(ip
)->z_is_ctldir
);
153 zfsctl_is_snapdir(struct inode
*ip
)
155 return (zfsctl_is_node(ip
) && (ip
->i_ino
<= ZFSCTL_INO_SNAPDIRS
));
159 * Allocate a new inode with the passed id and ops.
161 static struct inode
*
162 zfsctl_inode_alloc(zfs_sb_t
*zsb
, uint64_t id
,
163 const struct file_operations
*fops
, const struct inode_operations
*ops
)
165 struct timespec now
= current_fs_time(zsb
->z_sb
);
169 ip
= new_inode(zsb
->z_sb
);
174 ASSERT3P(zp
->z_dirlocks
, ==, NULL
);
175 ASSERT3P(zp
->z_acl_cached
, ==, NULL
);
176 ASSERT3P(zp
->z_xattr_cached
, ==, NULL
);
179 zp
->z_atime_dirty
= 0;
180 zp
->z_zn_prefetch
= 0;
196 zp
->z_is_zvol
= B_FALSE
;
197 zp
->z_is_mapped
= B_FALSE
;
198 zp
->z_is_ctldir
= B_TRUE
;
199 zp
->z_is_sa
= B_FALSE
;
201 ip
->i_mode
= (S_IFDIR
| S_IRUGO
| S_IXUGO
);
204 ip
->i_blkbits
= SPA_MINBLOCKSHIFT
;
211 if (insert_inode_locked(ip
)) {
212 unlock_new_inode(ip
);
217 mutex_enter(&zsb
->z_znodes_lock
);
218 list_insert_tail(&zsb
->z_all_znodes
, zp
);
221 mutex_exit(&zsb
->z_znodes_lock
);
223 unlock_new_inode(ip
);
229 * Lookup the inode with given id, it will be allocated if needed.
231 static struct inode
*
232 zfsctl_inode_lookup(zfs_sb_t
*zsb
, uint64_t id
,
233 const struct file_operations
*fops
, const struct inode_operations
*ops
)
235 struct inode
*ip
= NULL
;
238 ip
= ilookup(zsb
->z_sb
, (unsigned long)id
);
242 /* May fail due to concurrent zfsctl_inode_alloc() */
243 ip
= zfsctl_inode_alloc(zsb
, id
, fops
, ops
);
250 * Free zfsctl inode specific structures, currently there are none.
253 zfsctl_inode_destroy(struct inode
*ip
)
259 * An inode is being evicted from the cache.
262 zfsctl_inode_inactive(struct inode
*ip
)
264 if (zfsctl_is_snapdir(ip
))
265 zfsctl_snapdir_inactive(ip
);
269 * Create the '.zfs' directory. This directory is cached as part of the VFS
270 * structure. This results in a hold on the zfs_sb_t. The code in zfs_umount()
271 * therefore checks against a vfs_count of 2 instead of 1. This reference
272 * is removed when the ctldir is destroyed in the unmount. All other entities
273 * under the '.zfs' directory are created dynamically as needed.
275 * Because the dynamically created '.zfs' directory entries assume the use
276 * of 64-bit inode numbers this support must be disabled on 32-bit systems.
279 zfsctl_create(zfs_sb_t
*zsb
)
281 #if defined(CONFIG_64BIT)
282 ASSERT(zsb
->z_ctldir
== NULL
);
284 zsb
->z_ctldir
= zfsctl_inode_alloc(zsb
, ZFSCTL_INO_ROOT
,
285 &zpl_fops_root
, &zpl_ops_root
);
286 if (zsb
->z_ctldir
== NULL
)
292 #endif /* CONFIG_64BIT */
296 * Destroy the '.zfs' directory. Only called when the filesystem is unmounted.
299 zfsctl_destroy(zfs_sb_t
*zsb
)
302 zsb
->z_ctldir
= NULL
;
306 * Given a root znode, retrieve the associated .zfs directory.
307 * Add a hold to the vnode and return it.
310 zfsctl_root(znode_t
*zp
)
312 ASSERT(zfs_has_ctldir(zp
));
313 igrab(ZTOZSB(zp
)->z_ctldir
);
314 return (ZTOZSB(zp
)->z_ctldir
);
319 zfsctl_fid(struct inode
*ip
, fid_t
*fidp
)
321 znode_t
*zp
= ITOZ(ip
);
322 zfs_sb_t
*zsb
= ITOZSB(ip
);
323 uint64_t object
= zp
->z_id
;
329 if (fidp
->fid_len
< SHORT_FID_LEN
) {
330 fidp
->fid_len
= SHORT_FID_LEN
;
335 zfid
= (zfid_short_t
*)fidp
;
337 zfid
->zf_len
= SHORT_FID_LEN
;
339 for (i
= 0; i
< sizeof (zfid
->zf_object
); i
++)
340 zfid
->zf_object
[i
] = (uint8_t)(object
>> (8 * i
));
342 /* .zfs znodes always have a generation number of 0 */
343 for (i
= 0; i
< sizeof (zfid
->zf_gen
); i
++)
351 zfsctl_snapshot_zname(struct inode
*ip
, const char *name
, int len
, char *zname
)
353 objset_t
*os
= ITOZSB(ip
)->z_os
;
355 if (snapshot_namecheck(name
, NULL
, NULL
) != 0)
358 dmu_objset_name(os
, zname
);
359 if ((strlen(zname
) + 1 + strlen(name
)) >= len
)
360 return (ENAMETOOLONG
);
362 (void) strcat(zname
, "@");
363 (void) strcat(zname
, name
);
369 zfsctl_snapshot_zpath(struct path
*path
, int len
, char *zpath
)
371 char *path_buffer
, *path_ptr
;
372 int path_len
, error
= 0;
374 path_buffer
= kmem_alloc(len
, KM_SLEEP
);
376 path_ptr
= d_path(path
, path_buffer
, len
);
377 if (IS_ERR(path_ptr
)) {
378 error
= -PTR_ERR(path_ptr
);
382 path_len
= path_buffer
+ len
- 1 - path_ptr
;
383 if (path_len
> len
) {
388 memcpy(zpath
, path_ptr
, path_len
);
389 zpath
[path_len
] = '\0';
391 kmem_free(path_buffer
, len
);
397 * Special case the handling of "..".
401 zfsctl_root_lookup(struct inode
*dip
, char *name
, struct inode
**ipp
,
402 int flags
, cred_t
*cr
, int *direntflags
, pathname_t
*realpnp
)
404 zfs_sb_t
*zsb
= ITOZSB(dip
);
409 if (strcmp(name
, "..") == 0) {
410 *ipp
= dip
->i_sb
->s_root
->d_inode
;
411 } else if (strcmp(name
, ZFS_SNAPDIR_NAME
) == 0) {
412 *ipp
= zfsctl_inode_lookup(zsb
, ZFSCTL_INO_SNAPDIR
,
413 &zpl_fops_snapdir
, &zpl_ops_snapdir
);
414 } else if (strcmp(name
, ZFS_SHAREDIR_NAME
) == 0) {
415 *ipp
= zfsctl_inode_lookup(zsb
, ZFSCTL_INO_SHARES
,
416 &zpl_fops_shares
, &zpl_ops_shares
);
430 * Lookup entry point for the 'snapshot' directory. Try to open the
431 * snapshot if it exist, creating the pseudo filesystem inode as necessary.
432 * Perform a mount of the associated dataset on top of the inode.
436 zfsctl_snapdir_lookup(struct inode
*dip
, char *name
, struct inode
**ipp
,
437 int flags
, cred_t
*cr
, int *direntflags
, pathname_t
*realpnp
)
439 zfs_sb_t
*zsb
= ITOZSB(dip
);
445 error
= dmu_snapshot_id(zsb
->z_os
, name
, &id
);
451 *ipp
= zfsctl_inode_lookup(zsb
, ZFSCTL_INO_SNAPDIRS
- id
,
452 &simple_dir_operations
, &simple_dir_inode_operations
);
454 #ifdef HAVE_AUTOMOUNT
455 (*ipp
)->i_flags
|= S_AUTOMOUNT
;
456 #endif /* HAVE_AUTOMOUNT */
467 zfsctl_rename_snap(zfs_sb_t
*zsb
, zfs_snapentry_t
*sep
, const char *name
)
471 ASSERT(MUTEX_HELD(&zsb
->z_ctldir_lock
));
475 * Change the name in the AVL tree.
477 avl_remove(&zsb
->z_ctldir_snaps
, sep
);
478 (void) strcpy(sep
->se_name
, name
);
479 VERIFY(avl_find(&zsb
->z_ctldir_snaps
, sep
, &where
) == NULL
);
480 avl_insert(&zsb
->z_ctldir_snaps
, sep
, where
);
484 * Renaming a directory under '.zfs/snapshot' will automatically trigger
485 * a rename of the snapshot to the new given name. The rename is confined
486 * to the '.zfs/snapshot' directory snapshots cannot be moved elsewhere.
490 zfsctl_snapdir_rename(struct inode
*sdip
, char *sname
,
491 struct inode
*tdip
, char *tname
, cred_t
*cr
, int flags
)
493 zfs_sb_t
*zsb
= ITOZSB(sdip
);
494 zfs_snapentry_t search
, *sep
;
496 char *to
, *from
, *real
;
501 to
= kmem_alloc(MAXNAMELEN
, KM_SLEEP
);
502 from
= kmem_alloc(MAXNAMELEN
, KM_SLEEP
);
503 real
= kmem_alloc(MAXNAMELEN
, KM_SLEEP
);
505 if (zsb
->z_case
== ZFS_CASE_INSENSITIVE
) {
506 error
= dmu_snapshot_realname(zsb
->z_os
, sname
, real
,
510 } else if (error
!= ENOTSUP
) {
515 error
= zfsctl_snapshot_zname(sdip
, sname
, MAXNAMELEN
, from
);
517 error
= zfsctl_snapshot_zname(tdip
, tname
, MAXNAMELEN
, to
);
519 error
= zfs_secpolicy_rename_perms(from
, to
, cr
);
524 * Cannot move snapshots out of the snapdir.
532 * No-op when names are identical.
534 if (strcmp(sname
, tname
) == 0) {
539 mutex_enter(&zsb
->z_ctldir_lock
);
541 error
= dmu_objset_rename(from
, to
, B_FALSE
);
545 search
.se_name
= (char *)sname
;
546 sep
= avl_find(&zsb
->z_ctldir_snaps
, &search
, &where
);
548 zfsctl_rename_snap(zsb
, sep
, tname
);
551 mutex_exit(&zsb
->z_ctldir_lock
);
553 kmem_free(from
, MAXNAMELEN
);
554 kmem_free(to
, MAXNAMELEN
);
555 kmem_free(real
, MAXNAMELEN
);
563 * Removing a directory under '.zfs/snapshot' will automatically trigger
564 * the removal of the snapshot with the given name.
568 zfsctl_snapdir_remove(struct inode
*dip
, char *name
, cred_t
*cr
, int flags
)
570 zfs_sb_t
*zsb
= ITOZSB(dip
);
571 char *snapname
, *real
;
576 snapname
= kmem_alloc(MAXNAMELEN
, KM_SLEEP
);
577 real
= kmem_alloc(MAXNAMELEN
, KM_SLEEP
);
579 if (zsb
->z_case
== ZFS_CASE_INSENSITIVE
) {
580 error
= dmu_snapshot_realname(zsb
->z_os
, name
, real
,
584 } else if (error
!= ENOTSUP
) {
589 error
= zfsctl_snapshot_zname(dip
, name
, MAXNAMELEN
, snapname
);
591 error
= zfs_secpolicy_destroy_perms(snapname
, cr
);
595 error
= zfsctl_unmount_snapshot(zsb
, name
, MNT_FORCE
);
596 if ((error
== 0) || (error
== ENOENT
))
597 error
= dmu_objset_destroy(snapname
, B_FALSE
);
599 kmem_free(snapname
, MAXNAMELEN
);
600 kmem_free(real
, MAXNAMELEN
);
608 * Creating a directory under '.zfs/snapshot' will automatically trigger
609 * the creation of a new snapshot with the given name.
613 zfsctl_snapdir_mkdir(struct inode
*dip
, char *dirname
, vattr_t
*vap
,
614 struct inode
**ipp
, cred_t
*cr
, int flags
)
616 zfs_sb_t
*zsb
= ITOZSB(dip
);
620 dsname
= kmem_alloc(MAXNAMELEN
, KM_SLEEP
);
622 if (snapshot_namecheck(dirname
, NULL
, NULL
) != 0) {
627 dmu_objset_name(zsb
->z_os
, dsname
);
629 error
= zfs_secpolicy_snapshot_perms(dsname
, cr
);
634 error
= dmu_objset_snapshot(dsname
, dirname
,
635 NULL
, NULL
, B_FALSE
, B_FALSE
, -1);
639 error
= zfsctl_snapdir_lookup(dip
, dirname
, ipp
,
643 kmem_free(dsname
, MAXNAMELEN
);
649 * When a .zfs/snapshot/<snapshot> inode is evicted they must be removed
650 * from the snapshot list. This will normally happen as part of the auto
651 * unmount, however in the case of a manual snapshot unmount this will be
652 * the only notification we receive.
655 zfsctl_snapdir_inactive(struct inode
*ip
)
657 zfs_sb_t
*zsb
= ITOZSB(ip
);
658 zfs_snapentry_t
*sep
, *next
;
660 mutex_enter(&zsb
->z_ctldir_lock
);
662 sep
= avl_first(&zsb
->z_ctldir_snaps
);
663 while (sep
!= NULL
) {
664 next
= AVL_NEXT(&zsb
->z_ctldir_snaps
, sep
);
666 if (sep
->se_inode
== ip
) {
667 avl_remove(&zsb
->z_ctldir_snaps
, sep
);
668 taskq_cancel_id(zfs_expire_taskq
, sep
->se_taskqid
);
669 zfsctl_sep_free(sep
);
675 mutex_exit(&zsb
->z_ctldir_lock
);
679 * Attempt to unmount a snapshot by making a call to user space.
680 * There is no assurance that this can or will succeed, is just a
681 * best effort. In the case where it does fail, perhaps because
682 * it's in use, the unmount will fail harmlessly.
684 #define SET_UNMOUNT_CMD \
685 "exec 0</dev/null " \
688 "umount -t zfs -n '%s%s'"
691 __zfsctl_unmount_snapshot(zfs_snapentry_t
*sep
, int flags
)
693 char *argv
[] = { "/bin/sh", "-c", NULL
, NULL
};
694 char *envp
[] = { NULL
};
697 argv
[2] = kmem_asprintf(SET_UNMOUNT_CMD
,
698 flags
& MNT_FORCE
? "-f " : "", sep
->se_path
);
699 error
= call_usermodehelper(argv
[0], argv
, envp
, UMH_WAIT_PROC
);
703 * The umount system utility will return 256 on error. We must
704 * assume this error is because the file system is busy so it is
705 * converted to the more sensible EBUSY.
711 * This was the result of a manual unmount, cancel the delayed work
712 * to prevent zfsctl_expire_snapshot() from attempting a unmount.
714 if ((error
== 0) && !(flags
& MNT_EXPIRE
))
715 taskq_cancel_id(zfs_expire_taskq
, sep
->se_taskqid
);
722 zfsctl_unmount_snapshot(zfs_sb_t
*zsb
, char *name
, int flags
)
724 zfs_snapentry_t search
;
725 zfs_snapentry_t
*sep
;
728 mutex_enter(&zsb
->z_ctldir_lock
);
730 search
.se_name
= name
;
731 sep
= avl_find(&zsb
->z_ctldir_snaps
, &search
, NULL
);
733 avl_remove(&zsb
->z_ctldir_snaps
, sep
);
734 error
= __zfsctl_unmount_snapshot(sep
, flags
);
736 avl_add(&zsb
->z_ctldir_snaps
, sep
);
738 zfsctl_sep_free(sep
);
743 mutex_exit(&zsb
->z_ctldir_lock
);
744 ASSERT3S(error
, >=, 0);
750 * Traverse all mounted snapshots and attempt to unmount them. This
751 * is best effort, on failure EEXIST is returned and count will be set
752 * to the number of file snapshots which could not be unmounted.
755 zfsctl_unmount_snapshots(zfs_sb_t
*zsb
, int flags
, int *count
)
757 zfs_snapentry_t
*sep
, *next
;
762 ASSERT(zsb
->z_ctldir
!= NULL
);
763 mutex_enter(&zsb
->z_ctldir_lock
);
765 sep
= avl_first(&zsb
->z_ctldir_snaps
);
766 while (sep
!= NULL
) {
767 next
= AVL_NEXT(&zsb
->z_ctldir_snaps
, sep
);
768 avl_remove(&zsb
->z_ctldir_snaps
, sep
);
769 error
= __zfsctl_unmount_snapshot(sep
, flags
);
770 if (error
== EBUSY
) {
771 avl_add(&zsb
->z_ctldir_snaps
, sep
);
774 zfsctl_sep_free(sep
);
780 mutex_exit(&zsb
->z_ctldir_lock
);
782 return ((*count
> 0) ? EEXIST
: 0);
785 #define SET_MOUNT_CMD \
786 "exec 0</dev/null " \
789 "mount -t zfs -n '%s' '%s'"
792 zfsctl_mount_snapshot(struct path
*path
, int flags
)
794 struct dentry
*dentry
= path
->dentry
;
795 struct inode
*ip
= dentry
->d_inode
;
796 zfs_sb_t
*zsb
= ITOZSB(ip
);
797 char *full_name
, *full_path
;
798 zfs_snapentry_t
*sep
;
799 zfs_snapentry_t search
;
800 char *argv
[] = { "/bin/sh", "-c", NULL
, NULL
};
801 char *envp
[] = { NULL
};
806 full_name
= kmem_zalloc(MAXNAMELEN
, KM_SLEEP
);
807 full_path
= kmem_zalloc(PATH_MAX
, KM_SLEEP
);
809 error
= zfsctl_snapshot_zname(ip
, dname(dentry
), MAXNAMELEN
, full_name
);
813 error
= zfsctl_snapshot_zpath(path
, PATH_MAX
, full_path
);
818 * Attempt to mount the snapshot from user space. Normally this
819 * would be done using the vfs_kern_mount() function, however that
820 * function is marked GPL-only and cannot be used. On error we
821 * careful to log the real error to the console and return EISDIR
822 * to safely abort the automount. This should be very rare.
824 argv
[2] = kmem_asprintf(SET_MOUNT_CMD
, full_name
, full_path
);
825 error
= call_usermodehelper(argv
[0], argv
, envp
, UMH_WAIT_PROC
);
828 printk("ZFS: Unable to automount %s at %s: %d\n",
829 full_name
, full_path
, error
);
834 mutex_enter(&zsb
->z_ctldir_lock
);
837 * Ensure a previous entry does not exist, if it does safely remove
838 * it any cancel the outstanding expiration. This can occur when a
839 * snapshot is manually unmounted and then an automount is triggered.
841 search
.se_name
= full_name
;
842 sep
= avl_find(&zsb
->z_ctldir_snaps
, &search
, NULL
);
844 avl_remove(&zsb
->z_ctldir_snaps
, sep
);
845 taskq_cancel_id(zfs_expire_taskq
, sep
->se_taskqid
);
846 zfsctl_sep_free(sep
);
849 sep
= zfsctl_sep_alloc();
850 sep
->se_name
= full_name
;
851 sep
->se_path
= full_path
;
853 avl_add(&zsb
->z_ctldir_snaps
, sep
);
855 sep
->se_taskqid
= taskq_dispatch_delay(zfs_expire_taskq
,
856 zfsctl_expire_snapshot
, sep
, TQ_SLEEP
,
857 ddi_get_lbolt() + zfs_expire_snapshot
* HZ
);
859 mutex_exit(&zsb
->z_ctldir_lock
);
862 kmem_free(full_name
, MAXNAMELEN
);
863 kmem_free(full_path
, PATH_MAX
);
872 * Check if this super block has a matching objset id.
875 zfsctl_test_super(struct super_block
*sb
, void *objsetidp
)
877 zfs_sb_t
*zsb
= sb
->s_fs_info
;
878 uint64_t objsetid
= *(uint64_t *)objsetidp
;
880 return (dmu_objset_id(zsb
->z_os
) == objsetid
);
884 * Prevent a new super block from being allocated if an existing one
885 * could not be located. We only want to preform a lookup operation.
888 zfsctl_set_super(struct super_block
*sb
, void *objsetidp
)
894 zfsctl_lookup_objset(struct super_block
*sb
, uint64_t objsetid
, zfs_sb_t
**zsbp
)
896 zfs_sb_t
*zsb
= sb
->s_fs_info
;
897 struct super_block
*sbp
;
898 zfs_snapentry_t
*sep
;
902 ASSERT(zsb
->z_ctldir
!= NULL
);
904 mutex_enter(&zsb
->z_ctldir_lock
);
907 * Verify that the snapshot is mounted.
909 sep
= avl_first(&zsb
->z_ctldir_snaps
);
910 while (sep
!= NULL
) {
911 error
= dmu_snapshot_id(zsb
->z_os
, sep
->se_name
, &id
);
918 sep
= AVL_NEXT(&zsb
->z_ctldir_snaps
, sep
);
923 * Lookup the mounted root rather than the covered mount
924 * point. This may fail if the snapshot has just been
925 * unmounted by an unrelated user space process. This
926 * race cannot occur to an expired mount point because
927 * we hold the zsb->z_ctldir_lock to prevent the race.
929 sbp
= zpl_sget(&zpl_fs_type
, zfsctl_test_super
,
930 zfsctl_set_super
, 0, &id
);
932 error
= -PTR_ERR(sbp
);
934 *zsbp
= sbp
->s_fs_info
;
935 deactivate_super(sbp
);
941 mutex_exit(&zsb
->z_ctldir_lock
);
942 ASSERT3S(error
, >=, 0);
949 zfsctl_shares_lookup(struct inode
*dip
, char *name
, struct inode
**ipp
,
950 int flags
, cred_t
*cr
, int *direntflags
, pathname_t
*realpnp
)
952 zfs_sb_t
*zsb
= ITOZSB(dip
);
959 if (zsb
->z_shares_dir
== 0) {
964 error
= zfs_zget(zsb
, zsb
->z_shares_dir
, &dzp
);
970 error
= zfs_lookup(ZTOI(dzp
), name
, &ip
, 0, cr
, NULL
, NULL
);
980 * Initialize the various pieces we'll need to create and manipulate .zfs
981 * directories. Currently this is unused but available.
986 zfs_expire_taskq
= taskq_create("z_unmount", 1, maxclsyspri
,
987 1, 8, TASKQ_PREPOPULATE
);
991 * Cleanup the various pieces we needed for .zfs directories. In particular
992 * ensure the expiry timer is canceled safely.
997 taskq_destroy(zfs_expire_taskq
);
1000 module_param(zfs_expire_snapshot
, int, 0644);
1001 MODULE_PARM_DESC(zfs_expire_snapshot
, "Seconds to expire .zfs/snapshot");