diff options
Diffstat (limited to 'sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c')
| -rw-r--r-- | sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c | 1120 |
1 files changed, 1120 insertions, 0 deletions
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c new file mode 100644 index 000000000000..c759962a6d11 --- /dev/null +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c @@ -0,0 +1,1120 @@ +/* + * 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 http://www.opensolaris.org/os/licensing. + * 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 2007 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#pragma ident "%Z%%M% %I% %E% SMI" + +/* + * ZFS control directory (a.k.a. ".zfs") + * + * This directory provides a common location for all ZFS meta-objects. + * Currently, this is only the 'snapshot' directory, but this may expand in the + * future. The elements are built using the GFS primitives, 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 vnode. + * + * All mounts are handled automatically by the kernel, but unmounts are + * (currently) handled from user land. The main reason is that there is no + * reliable way to auto-unmount the filesystem when it's "no longer in use". + * When the user unmounts a filesystem, we call zfsctl_unmount(), which + * unmounts any snapshots within the snapshot directory. + */ + +#include <sys/zfs_context.h> +#include <sys/zfs_ctldir.h> +#include <sys/zfs_ioctl.h> +#include <sys/zfs_vfsops.h> +#include <sys/namei.h> +#include <sys/gfs.h> +#include <sys/stat.h> +#include <sys/dmu.h> +#include <sys/mount.h> + +typedef struct { + char *se_name; + vnode_t *se_root; + avl_node_t se_node; +} zfs_snapentry_t; + +static int +snapentry_compare(const void *a, const void *b) +{ + const zfs_snapentry_t *sa = a; + const zfs_snapentry_t *sb = b; + int ret = strcmp(sa->se_name, sb->se_name); + + if (ret < 0) + return (-1); + else if (ret > 0) + return (1); + else + return (0); +} + +static struct vop_vector zfsctl_ops_root; +static struct vop_vector zfsctl_ops_snapdir; +static struct vop_vector zfsctl_ops_snapshot; + +static vnode_t *zfsctl_mknode_snapdir(vnode_t *); +static vnode_t *zfsctl_snapshot_mknode(vnode_t *, uint64_t objset); + +typedef struct zfsctl_node { + gfs_dir_t zc_gfs_private; + uint64_t zc_id; + timestruc_t zc_cmtime; /* ctime and mtime, always the same */ +} zfsctl_node_t; + +typedef struct zfsctl_snapdir { + zfsctl_node_t sd_node; + kmutex_t sd_lock; + avl_tree_t sd_snaps; +} zfsctl_snapdir_t; + +/* + * Root directory elements. We have only a single static entry, 'snapshot'. + */ +static gfs_dirent_t zfsctl_root_entries[] = { + { "snapshot", zfsctl_mknode_snapdir, GFS_CACHE_VNODE }, + { NULL } +}; + +/* include . and .. in the calculation */ +#define NROOT_ENTRIES ((sizeof (zfsctl_root_entries) / \ + sizeof (gfs_dirent_t)) + 1) + + +/* + * Initialize the various GFS pieces we'll need to create and manipulate .zfs + * directories. This is called from the ZFS init routine, and initializes the + * vnode ops vectors that we'll be using. + */ +void +zfsctl_init(void) +{ +} + +void +zfsctl_fini(void) +{ +} + +/* + * Return the inode number associated with the 'snapshot' directory. + */ +/* ARGSUSED */ +static ino64_t +zfsctl_root_inode_cb(vnode_t *vp, int index) +{ + ASSERT(index == 0); + return (ZFSCTL_INO_SNAPDIR); +} + +/* + * Create the '.zfs' directory. This directory is cached as part of the VFS + * structure. This results in a hold on the vfs_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. + */ +void +zfsctl_create(zfsvfs_t *zfsvfs) +{ + vnode_t *vp, *rvp; + zfsctl_node_t *zcp; + + ASSERT(zfsvfs->z_ctldir == NULL); + + vp = gfs_root_create(sizeof (zfsctl_node_t), zfsvfs->z_vfs, + &zfsctl_ops_root, ZFSCTL_INO_ROOT, zfsctl_root_entries, + zfsctl_root_inode_cb, MAXNAMELEN, NULL, NULL); + zcp = vp->v_data; + zcp->zc_id = ZFSCTL_INO_ROOT; + + VERIFY(VFS_ROOT(zfsvfs->z_vfs, LK_EXCLUSIVE, &rvp, curthread) == 0); + ZFS_TIME_DECODE(&zcp->zc_cmtime, VTOZ(rvp)->z_phys->zp_crtime); + VN_URELE(rvp); + + /* + * We're only faking the fact that we have a root of a filesystem for + * the sake of the GFS interfaces. Undo the flag manipulation it did + * for us. + */ + vp->v_vflag &= ~VV_ROOT; + + zfsvfs->z_ctldir = vp; +} + +/* + * Destroy the '.zfs' directory. Only called when the filesystem is unmounted. + * There might still be more references if we were force unmounted, but only + * new zfs_inactive() calls can occur and they don't reference .zfs + */ +void +zfsctl_destroy(zfsvfs_t *zfsvfs) +{ + VN_RELE(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. + */ +vnode_t * +zfsctl_root(znode_t *zp) +{ + ASSERT(zfs_has_ctldir(zp)); + VN_HOLD(zp->z_zfsvfs->z_ctldir); + return (zp->z_zfsvfs->z_ctldir); +} + +/* + * Common open routine. Disallow any write access. + */ +/* ARGSUSED */ +static int +zfsctl_common_open(struct vop_open_args *ap) +{ + int flags = ap->a_mode; + + if (flags & FWRITE) + return (EACCES); + + return (0); +} + +/* + * Common close routine. Nothing to do here. + */ +/* ARGSUSED */ +static int +zfsctl_common_close(struct vop_close_args *ap) +{ + return (0); +} + +/* + * Common access routine. Disallow writes. + */ +/* ARGSUSED */ +static int +zfsctl_common_access(ap) + struct vop_access_args /* { + struct vnode *a_vp; + int a_mode; + struct ucred *a_cred; + struct thread *a_td; + } */ *ap; +{ + int mode = ap->a_mode; + + if (mode & VWRITE) + return (EACCES); + + return (0); +} + +/* + * Common getattr function. Fill in basic information. + */ +static void +zfsctl_common_getattr(vnode_t *vp, vattr_t *vap) +{ + zfsctl_node_t *zcp = vp->v_data; + timestruc_t now; + + vap->va_uid = 0; + vap->va_gid = 0; + vap->va_rdev = 0; + /* + * We are a purly virtual object, so we have no + * blocksize or allocated blocks. + */ + vap->va_blksize = 0; + vap->va_nblocks = 0; + vap->va_seq = 0; + vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0]; + vap->va_mode = S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | + S_IROTH | S_IXOTH; + vap->va_type = VDIR; + /* + * We live in the now (for atime). + */ + gethrestime(&now); + vap->va_atime = now; + vap->va_mtime = vap->va_ctime = vap->va_birthtime = zcp->zc_cmtime; + /* FreeBSD: Reset chflags(2) flags. */ + vap->va_flags = 0; +} + +static int +zfsctl_common_fid(ap) + struct vop_fid_args /* { + struct vnode *a_vp; + struct fid *a_fid; + } */ *ap; +{ + vnode_t *vp = ap->a_vp; + fid_t *fidp = (void *)ap->a_fid; + zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; + zfsctl_node_t *zcp = vp->v_data; + uint64_t object = zcp->zc_id; + zfid_short_t *zfid; + int i; + + ZFS_ENTER(zfsvfs); + + fidp->fid_len = SHORT_FID_LEN; + + 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); + return (0); +} + +static int +zfsctl_common_reclaim(ap) + struct vop_reclaim_args /* { + struct vnode *a_vp; + struct thread *a_td; + } */ *ap; +{ + vnode_t *vp = ap->a_vp; + + /* + * Destroy the vm object and flush associated pages. + */ + vnode_destroy_vobject(vp); + VI_LOCK(vp); + vp->v_data = NULL; + VI_UNLOCK(vp); + return (0); +} + +/* + * .zfs inode namespace + * + * We need to generate unique inode numbers for all files and directories + * within the .zfs pseudo-filesystem. We use the following scheme: + * + * ENTRY ZFSCTL_INODE + * .zfs 1 + * .zfs/snapshot 2 + * .zfs/snapshot/<snap> objectid(snap) + */ + +#define ZFSCTL_INO_SNAP(id) (id) + +/* + * Get root directory attributes. + */ +/* ARGSUSED */ +static int +zfsctl_root_getattr(ap) + struct vop_getattr_args /* { + struct vnode *a_vp; + struct vattr *a_vap; + struct ucred *a_cred; + struct thread *a_td; + } */ *ap; +{ + struct vnode *vp = ap->a_vp; + struct vattr *vap = ap->a_vap; + zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; + + ZFS_ENTER(zfsvfs); + vap->va_nodeid = ZFSCTL_INO_ROOT; + vap->va_nlink = vap->va_size = NROOT_ENTRIES; + + zfsctl_common_getattr(vp, vap); + ZFS_EXIT(zfsvfs); + + return (0); +} + +/* + * Special case the handling of "..". + */ +/* ARGSUSED */ +int +zfsctl_root_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp, + int flags, vnode_t *rdir, cred_t *cr) +{ + zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data; + int err; + + ZFS_ENTER(zfsvfs); + + if (strcmp(nm, "..") == 0) { + err = VFS_ROOT(dvp->v_vfsp, LK_EXCLUSIVE, vpp, curthread); + if (err == 0) + VOP_UNLOCK(*vpp, 0, curthread); + } else { + err = gfs_dir_lookup(dvp, nm, vpp); + } + + ZFS_EXIT(zfsvfs); + + return (err); +} + +/* + * Special case the handling of "..". + */ +/* ARGSUSED */ +int +zfsctl_root_lookup_vop(ap) + struct vop_lookup_args /* { + struct vnode *a_dvp; + struct vnode **a_vpp; + struct componentname *a_cnp; + } */ *ap; +{ + vnode_t *dvp = ap->a_dvp; + vnode_t **vpp = ap->a_vpp; + cred_t *cr = ap->a_cnp->cn_cred; + int flags = ap->a_cnp->cn_flags; + int nameiop = ap->a_cnp->cn_nameiop; + char nm[NAME_MAX + 1]; + int err; + + if ((flags & ISLASTCN) && (nameiop == RENAME || nameiop == CREATE)) + return (EOPNOTSUPP); + + ASSERT(ap->a_cnp->cn_namelen < sizeof(nm)); + strlcpy(nm, ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen + 1); + + err = zfsctl_root_lookup(dvp, nm, vpp, NULL, 0, NULL, cr); + if (err == 0 && (nm[0] != '.' || nm[1] != '\0')) + vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY, ap->a_cnp->cn_thread); + + return (err); +} + +static struct vop_vector zfsctl_ops_root = { + .vop_default = &default_vnodeops, + .vop_open = zfsctl_common_open, + .vop_close = zfsctl_common_close, + .vop_ioctl = VOP_EINVAL, + .vop_getattr = zfsctl_root_getattr, + .vop_access = zfsctl_common_access, + .vop_readdir = gfs_vop_readdir, + .vop_lookup = zfsctl_root_lookup_vop, + .vop_inactive = gfs_vop_inactive, + .vop_reclaim = zfsctl_common_reclaim, + .vop_fid = zfsctl_common_fid, +}; + +static int +zfsctl_snapshot_zname(vnode_t *vp, const char *name, int len, char *zname) +{ + objset_t *os = ((zfsvfs_t *)((vp)->v_vfsp->vfs_data))->z_os; + + dmu_objset_name(os, zname); + if (strlen(zname) + 1 + strlen(name) >= len) + return (ENAMETOOLONG); + (void) strcat(zname, "@"); + (void) strcat(zname, name); + return (0); +} + +static int +zfsctl_unmount_snap(vnode_t *dvp, const char *name, int force, cred_t *cr) +{ + zfsctl_snapdir_t *sdp = dvp->v_data; + zfs_snapentry_t search, *sep; + struct vop_inactive_args ap; + avl_index_t where; + int err; + + ASSERT(MUTEX_HELD(&sdp->sd_lock)); + + search.se_name = (char *)name; + if ((sep = avl_find(&sdp->sd_snaps, &search, &where)) == NULL) + return (ENOENT); + + ASSERT(vn_ismntpt(sep->se_root)); + + /* this will be dropped by dounmount() */ + if ((err = vn_vfswlock(sep->se_root)) != 0) + return (err); + + err = dounmount(vn_mountedvfs(sep->se_root), force, curthread); + if (err) + return (err); + ASSERT(sep->se_root->v_count == 1); + ap.a_vp = sep->se_root; + gfs_vop_inactive(&ap); + + avl_remove(&sdp->sd_snaps, sep); + kmem_free(sep->se_name, strlen(sep->se_name) + 1); + kmem_free(sep, sizeof (zfs_snapentry_t)); + + return (0); +} + +#if 0 +static void +zfsctl_rename_snap(zfsctl_snapdir_t *sdp, zfs_snapentry_t *sep, const char *nm) +{ + avl_index_t where; + vfs_t *vfsp; + refstr_t *pathref; + char newpath[MAXNAMELEN]; + char *tail; + + ASSERT(MUTEX_HELD(&sdp->sd_lock)); + ASSERT(sep != NULL); + + vfsp = vn_mountedvfs(sep->se_root); + ASSERT(vfsp != NULL); + + vfs_lock_wait(vfsp); + + /* + * Change the name in the AVL tree. + */ + avl_remove(&sdp->sd_snaps, sep); + kmem_free(sep->se_name, strlen(sep->se_name) + 1); + sep->se_name = kmem_alloc(strlen(nm) + 1, KM_SLEEP); + (void) strcpy(sep->se_name, nm); + VERIFY(avl_find(&sdp->sd_snaps, sep, &where) == NULL); + avl_insert(&sdp->sd_snaps, sep, where); + + /* + * Change the current mountpoint info: + * - update the tail of the mntpoint path + * - update the tail of the resource path + */ + pathref = vfs_getmntpoint(vfsp); + (void) strncpy(newpath, refstr_value(pathref), sizeof (newpath)); + VERIFY((tail = strrchr(newpath, '/')) != NULL); + *(tail+1) = '\0'; + ASSERT3U(strlen(newpath) + strlen(nm), <, sizeof (newpath)); + (void) strcat(newpath, nm); + refstr_rele(pathref); + vfs_setmntpoint(vfsp, newpath); + + pathref = vfs_getresource(vfsp); + (void) strncpy(newpath, refstr_value(pathref), sizeof (newpath)); + VERIFY((tail = strrchr(newpath, '@')) != NULL); + *(tail+1) = '\0'; + ASSERT3U(strlen(newpath) + strlen(nm), <, sizeof (newpath)); + (void) strcat(newpath, nm); + refstr_rele(pathref); + vfs_setresource(vfsp, newpath); + + vfs_unlock(vfsp); +} +#endif + +#if 0 +static int +zfsctl_snapdir_rename(vnode_t *sdvp, char *snm, vnode_t *tdvp, char *tnm, + cred_t *cr) +{ + zfsctl_snapdir_t *sdp = sdvp->v_data; + zfs_snapentry_t search, *sep; + avl_index_t where; + char from[MAXNAMELEN], to[MAXNAMELEN]; + int err; + + err = zfsctl_snapshot_zname(sdvp, snm, MAXNAMELEN, from); + if (err) + return (err); + err = zfs_secpolicy_write(from, cr); + if (err) + return (err); + + /* + * Cannot move snapshots out of the snapdir. + */ + if (sdvp != tdvp) + return (EINVAL); + + if (strcmp(snm, tnm) == 0) + return (0); + + err = zfsctl_snapshot_zname(tdvp, tnm, MAXNAMELEN, to); + if (err) + return (err); + + mutex_enter(&sdp->sd_lock); + + search.se_name = (char *)snm; + if ((sep = avl_find(&sdp->sd_snaps, &search, &where)) == NULL) { + mutex_exit(&sdp->sd_lock); + return (ENOENT); + } + + err = dmu_objset_rename(from, to); + if (err == 0) + zfsctl_rename_snap(sdp, sep, tnm); + + mutex_exit(&sdp->sd_lock); + + return (err); +} +#endif + +#if 0 +/* ARGSUSED */ +static int +zfsctl_snapdir_remove(vnode_t *dvp, char *name, vnode_t *cwd, cred_t *cr) +{ + zfsctl_snapdir_t *sdp = dvp->v_data; + char snapname[MAXNAMELEN]; + int err; + + err = zfsctl_snapshot_zname(dvp, name, MAXNAMELEN, snapname); + if (err) + return (err); + err = zfs_secpolicy_write(snapname, cr); + if (err) + return (err); + + mutex_enter(&sdp->sd_lock); + + err = zfsctl_unmount_snap(dvp, name, 0, cr); + if (err) { + mutex_exit(&sdp->sd_lock); + return (err); + } + + err = dmu_objset_destroy(snapname); + + mutex_exit(&sdp->sd_lock); + + return (err); +} +#endif + +/* + * Lookup entry point for the 'snapshot' directory. Try to open the + * snapshot if it exist, creating the pseudo filesystem vnode as necessary. + * Perform a mount of the associated dataset on top of the vnode. + */ +/* ARGSUSED */ +int +zfsctl_snapdir_lookup(ap) + struct vop_lookup_args /* { + struct vnode *a_dvp; + struct vnode **a_vpp; + struct componentname *a_cnp; + } */ *ap; +{ + vnode_t *dvp = ap->a_dvp; + vnode_t **vpp = ap->a_vpp; + char nm[NAME_MAX + 1]; + zfsctl_snapdir_t *sdp = dvp->v_data; + objset_t *snap; + char snapname[MAXNAMELEN]; + char *mountpoint; + zfs_snapentry_t *sep, search; + size_t mountpoint_len; + avl_index_t where; + zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data; + int err; + + ASSERT(ap->a_cnp->cn_namelen < sizeof(nm)); + strlcpy(nm, ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen + 1); + + ASSERT(dvp->v_type == VDIR); + + if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) + return (0); + + *vpp = NULL; + + /* + * If we get a recursive call, that means we got called + * from the domount() code while it was trying to look up the + * spec (which looks like a local path for zfs). We need to + * add some flag to domount() to tell it not to do this lookup. + */ + if (MUTEX_HELD(&sdp->sd_lock)) + return (ENOENT); + + ZFS_ENTER(zfsvfs); + + mutex_enter(&sdp->sd_lock); + search.se_name = (char *)nm; + if ((sep = avl_find(&sdp->sd_snaps, &search, &where)) != NULL) { + *vpp = sep->se_root; + VN_HOLD(*vpp); + if ((*vpp)->v_mountedhere == NULL) { + /* + * The snapshot was unmounted behind our backs, + * try to remount it. + */ + goto domount; + } + vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY, ap->a_cnp->cn_thread); + mutex_exit(&sdp->sd_lock); + ZFS_EXIT(zfsvfs); + return (0); + } + + /* + * The requested snapshot is not currently mounted, look it up. + */ + err = zfsctl_snapshot_zname(dvp, nm, MAXNAMELEN, snapname); + if (err) { + mutex_exit(&sdp->sd_lock); + ZFS_EXIT(zfsvfs); + return (err); + } + if (dmu_objset_open(snapname, DMU_OST_ZFS, + DS_MODE_STANDARD | DS_MODE_READONLY, &snap) != 0) { + mutex_exit(&sdp->sd_lock); + ZFS_EXIT(zfsvfs); + return (ENOENT); + } + + sep = kmem_alloc(sizeof (zfs_snapentry_t), KM_SLEEP); + sep->se_name = kmem_alloc(strlen(nm) + 1, KM_SLEEP); + (void) strcpy(sep->se_name, nm); + *vpp = sep->se_root = zfsctl_snapshot_mknode(dvp, dmu_objset_id(snap)); + VN_HOLD(*vpp); + avl_insert(&sdp->sd_snaps, sep, where); + + dmu_objset_close(snap); +domount: + mountpoint_len = strlen(dvp->v_vfsp->mnt_stat.f_mntonname) + + strlen("/.zfs/snapshot/") + strlen(nm) + 1; + mountpoint = kmem_alloc(mountpoint_len, KM_SLEEP); + (void) snprintf(mountpoint, mountpoint_len, "%s/.zfs/snapshot/%s", + dvp->v_vfsp->mnt_stat.f_mntonname, nm); + err = domount(curthread, *vpp, "zfs", mountpoint, snapname, 0); + kmem_free(mountpoint, mountpoint_len); + /* FreeBSD: This line was moved from below to avoid a lock recursion. */ + if (err == 0) + vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY, curthread); + mutex_exit(&sdp->sd_lock); + + /* + * If we had an error, drop our hold on the vnode and + * zfsctl_snapshot_inactive() will clean up. + */ + if (err) { + VN_RELE(*vpp); + *vpp = NULL; + } + return (err); +} + +/* ARGSUSED */ +static int +zfsctl_snapdir_readdir_cb(vnode_t *vp, struct dirent64 *dp, int *eofp, + offset_t *offp, offset_t *nextp, void *data) +{ + zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; + char snapname[MAXNAMELEN]; + uint64_t id, cookie; + + ZFS_ENTER(zfsvfs); + + cookie = *offp; + if (dmu_snapshot_list_next(zfsvfs->z_os, MAXNAMELEN, snapname, &id, + &cookie) == ENOENT) { + *eofp = 1; + ZFS_EXIT(zfsvfs); + return (0); + } + + (void) strcpy(dp->d_name, snapname); + dp->d_ino = ZFSCTL_INO_SNAP(id); + *nextp = cookie; + + ZFS_EXIT(zfsvfs); + + return (0); +} + +vnode_t * +zfsctl_mknode_snapdir(vnode_t *pvp) +{ + vnode_t *vp; + zfsctl_snapdir_t *sdp; + + vp = gfs_dir_create(sizeof (zfsctl_snapdir_t), pvp, pvp->v_vfsp, + &zfsctl_ops_snapdir, NULL, NULL, MAXNAMELEN, + zfsctl_snapdir_readdir_cb, NULL); + sdp = vp->v_data; + sdp->sd_node.zc_id = ZFSCTL_INO_SNAPDIR; + sdp->sd_node.zc_cmtime = ((zfsctl_node_t *)pvp->v_data)->zc_cmtime; + mutex_init(&sdp->sd_lock, NULL, MUTEX_DEFAULT, NULL); + avl_create(&sdp->sd_snaps, snapentry_compare, + sizeof (zfs_snapentry_t), offsetof(zfs_snapentry_t, se_node)); + return (vp); +} + +/* ARGSUSED */ +static int +zfsctl_snapdir_getattr(ap) + struct vop_getattr_args /* { + struct vnode *a_vp; + struct vattr *a_vap; + struct ucred *a_cred; + struct thread *a_td; + } */ *ap; +{ + struct vnode *vp = ap->a_vp; + struct vattr *vap = ap->a_vap; + zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; + zfsctl_snapdir_t *sdp = vp->v_data; + + ZFS_ENTER(zfsvfs); + zfsctl_common_getattr(vp, vap); + vap->va_nodeid = gfs_file_inode(vp); + vap->va_nlink = vap->va_size = avl_numnodes(&sdp->sd_snaps) + 2; + ZFS_EXIT(zfsvfs); + + return (0); +} + +/* ARGSUSED */ +static int +zfsctl_snapdir_inactive(ap) + struct vop_inactive_args /* { + struct vnode *a_vp; + struct thread *a_td; + } */ *ap; +{ + vnode_t *vp = ap->a_vp; + zfsctl_snapdir_t *sdp = vp->v_data; + void *private; + + private = gfs_dir_inactive(vp); + if (private != NULL) { + ASSERT(avl_numnodes(&sdp->sd_snaps) == 0); + mutex_destroy(&sdp->sd_lock); + avl_destroy(&sdp->sd_snaps); + kmem_free(private, sizeof (zfsctl_snapdir_t)); + } + return (0); +} + +static struct vop_vector zfsctl_ops_snapdir = { + .vop_default = &default_vnodeops, + .vop_open = zfsctl_common_open, + .vop_close = zfsctl_common_close, + .vop_ioctl = VOP_EINVAL, + .vop_getattr = zfsctl_snapdir_getattr, + .vop_access = zfsctl_common_access, + .vop_readdir = gfs_vop_readdir, + .vop_lookup = zfsctl_snapdir_lookup, + .vop_inactive = zfsctl_snapdir_inactive, + .vop_reclaim = zfsctl_common_reclaim, + .vop_fid = zfsctl_common_fid, +}; + +static vnode_t * +zfsctl_snapshot_mknode(vnode_t *pvp, uint64_t objset) +{ + vnode_t *vp; + zfsctl_node_t *zcp; + + vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp, pvp->v_vfsp, + &zfsctl_ops_snapshot, NULL, NULL, MAXNAMELEN, NULL, NULL); + zcp = vp->v_data; + zcp->zc_id = objset; + + return (vp); +} + +static int +zfsctl_snapshot_inactive(ap) + struct vop_inactive_args /* { + struct vnode *a_vp; + struct thread *a_td; + } */ *ap; +{ + vnode_t *vp = ap->a_vp; + struct vop_inactive_args iap; + zfsctl_snapdir_t *sdp; + zfs_snapentry_t *sep, *next; + int locked; + vnode_t *dvp; + + VERIFY(gfs_dir_lookup(vp, "..", &dvp) == 0); + sdp = dvp->v_data; + VOP_UNLOCK(dvp, 0, ap->a_td); + + if (!(locked = MUTEX_HELD(&sdp->sd_lock))) + mutex_enter(&sdp->sd_lock); + + if (vp->v_count > 1) { + if (!locked) + mutex_exit(&sdp->sd_lock); + return (0); + } + ASSERT(!vn_ismntpt(vp)); + + sep = avl_first(&sdp->sd_snaps); + while (sep != NULL) { + next = AVL_NEXT(&sdp->sd_snaps, sep); + + if (sep->se_root == vp) { + avl_remove(&sdp->sd_snaps, sep); + kmem_free(sep->se_name, strlen(sep->se_name) + 1); + kmem_free(sep, sizeof (zfs_snapentry_t)); + break; + } + sep = next; + } + ASSERT(sep != NULL); + + if (!locked) + mutex_exit(&sdp->sd_lock); + VN_RELE(dvp); + + /* + * Dispose of the vnode for the snapshot mount point. + * This is safe to do because once this entry has been removed + * from the AVL tree, it can't be found again, so cannot become + * "active". If we lookup the same name again we will end up + * creating a new vnode. + */ + iap.a_vp = vp; + return (gfs_vop_inactive(&iap)); +} + +static int +zfsctl_traverse_begin(vnode_t **vpp, kthread_t *td) +{ + int err; + + VN_HOLD(*vpp); + /* Snapshot should be already mounted, but just in case. */ + if (vn_mountedvfs(*vpp) == NULL) + return (ENOENT); + err = traverse(vpp); + if (err == 0) + vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY, td); + return (err); +} + +static void +zfsctl_traverse_end(vnode_t *vp, int err) +{ + + if (err == 0) + vput(vp); + else + VN_RELE(vp); +} + +static int +zfsctl_snapshot_getattr(ap) + struct vop_getattr_args /* { + struct vnode *a_vp; + struct vattr *a_vap; + struct ucred *a_cred; + struct thread *a_td; + } */ *ap; +{ + vnode_t *vp = ap->a_vp; + int err; + + err = zfsctl_traverse_begin(&vp, ap->a_td); + if (err == 0) + err = VOP_GETATTR(vp, ap->a_vap, ap->a_cred, ap->a_td); + zfsctl_traverse_end(vp, err); + return (err); +} + +static int +zfsctl_snapshot_fid(ap) + struct vop_fid_args /* { + struct vnode *a_vp; + struct fid *a_fid; + } */ *ap; +{ + vnode_t *vp = ap->a_vp; + int err; + + err = zfsctl_traverse_begin(&vp, curthread); + if (err == 0) + err = VOP_VPTOFH(vp, (void *)ap->a_fid); + zfsctl_traverse_end(vp, err); + return (err); +} + +/* + * These VP's should never see the light of day. They should always + * be covered. + */ +static struct vop_vector zfsctl_ops_snapshot = { + .vop_default = &default_vnodeops, + .vop_inactive = zfsctl_snapshot_inactive, + .vop_reclaim = zfsctl_common_reclaim, + .vop_getattr = zfsctl_snapshot_getattr, + .vop_fid = zfsctl_snapshot_fid, +}; + +int +zfsctl_lookup_objset(vfs_t *vfsp, uint64_t objsetid, zfsvfs_t **zfsvfsp) +{ + zfsvfs_t *zfsvfs = vfsp->vfs_data; + vnode_t *dvp, *vp; + zfsctl_snapdir_t *sdp; + zfsctl_node_t *zcp; + zfs_snapentry_t *sep; + int error; + + ASSERT(zfsvfs->z_ctldir != NULL); + error = zfsctl_root_lookup(zfsvfs->z_ctldir, "snapshot", &dvp, + NULL, 0, NULL, kcred); + if (error != 0) + return (error); + sdp = dvp->v_data; + + mutex_enter(&sdp->sd_lock); + sep = avl_first(&sdp->sd_snaps); + while (sep != NULL) { + vp = sep->se_root; + zcp = vp->v_data; + if (zcp->zc_id == objsetid) + break; + + sep = AVL_NEXT(&sdp->sd_snaps, sep); + } + + if (sep != NULL) { + VN_HOLD(vp); + error = traverse(&vp); + if (error == 0) { + if (vp == sep->se_root) + error = EINVAL; + else + *zfsvfsp = VTOZ(vp)->z_zfsvfs; + } + mutex_exit(&sdp->sd_lock); + VN_RELE(vp); + } else { + error = EINVAL; + mutex_exit(&sdp->sd_lock); + } + + VN_RELE(dvp); + + return (error); +} + +/* + * Unmount any snapshots for the given filesystem. This is called from + * zfs_umount() - if we have a ctldir, then go through and unmount all the + * snapshots. + */ +int +zfsctl_umount_snapshots(vfs_t *vfsp, int fflags, cred_t *cr) +{ + struct vop_inactive_args ap; + zfsvfs_t *zfsvfs = vfsp->vfs_data; + vnode_t *dvp, *svp; + zfsctl_snapdir_t *sdp; + zfs_snapentry_t *sep, *next; + int error; + + ASSERT(zfsvfs->z_ctldir != NULL); + error = zfsctl_root_lookup(zfsvfs->z_ctldir, "snapshot", &dvp, + NULL, 0, NULL, cr); + if (error != 0) + return (error); + sdp = dvp->v_data; + + mutex_enter(&sdp->sd_lock); + + sep = avl_first(&sdp->sd_snaps); + while (sep != NULL) { + svp = sep->se_root; + next = AVL_NEXT(&sdp->sd_snaps, sep); + + /* + * If this snapshot is not mounted, then it must + * have just been unmounted by somebody else, and + * will be cleaned up by zfsctl_snapdir_inactive(). + */ + if (vn_ismntpt(svp)) { + if ((error = vn_vfswlock(svp)) != 0) + goto out; + + /* + * Increase usecount, so dounmount() won't vrele() it + * to 0 and call zfsctl_snapdir_inactive(). + */ + VN_HOLD(svp); + vfsp = vn_mountedvfs(svp); + mtx_lock(&Giant); + error = dounmount(vfsp, fflags, curthread); + mtx_unlock(&Giant); + if (error != 0) { + VN_RELE(svp); + goto out; + } + + avl_remove(&sdp->sd_snaps, sep); + kmem_free(sep->se_name, strlen(sep->se_name) + 1); + kmem_free(sep, sizeof (zfs_snapentry_t)); + + /* + * We can't use VN_RELE(), as that will try to + * invoke zfsctl_snapdir_inactive(), and that + * would lead to an attempt to re-grab the sd_lock. + */ + ASSERT3U(svp->v_count, ==, 1); + ap.a_vp = svp; + gfs_vop_inactive(&ap); + } + sep = next; + } +out: + mutex_exit(&sdp->sd_lock); + VN_RELE(dvp); + + return (error); +} |