/* * 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 (c) 2005, 2010, Oracle and/or its affiliates. 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' 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. * * The '.zfs', '.zfs/snapshot', and all directories created under * '.zfs/snapshot' (ie: '.zfs/snapshot/<snapname>') are all GFS nodes and * share the same vfs_t as the head filesystem (what '.zfs' lives under). * * File systems mounted ontop of the GFS nodes '.zfs/snapshot/<snapname>' * (ie: snapshots) are ZFS nodes and have their own unique vfs_t. * However, vnodes within these mounted on file systems have their v_vfsp * fields set to the head filesystem to make NFS happy (see * zfsctl_snapdir_lookup()). We VFS_HOLD the head filesystem's vfs_t * so that it cannot be freed until all snapshots have been unmounted. */ #include <fs/fs_subr.h> #include <sys/zfs_ctldir.h> #include <sys/zfs_ioctl.h> #include <sys/zfs_vfsops.h> #include <sys/vfs_opreg.h> #include <sys/gfs.h> #include <sys/stat.h> #include <sys/dmu.h> #include <sys/dsl_deleg.h> #include <sys/mount.h> #include <sys/sunddi.h> #include "zfs_namecheck.h" 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; 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); } vnodeops_t *zfsctl_ops_root; vnodeops_t *zfsctl_ops_snapdir; vnodeops_t *zfsctl_ops_snapshot; vnodeops_t *zfsctl_ops_shares; vnodeops_t *zfsctl_ops_shares_dir; static const fs_operation_def_t zfsctl_tops_root[]; static const fs_operation_def_t zfsctl_tops_snapdir[]; static const fs_operation_def_t zfsctl_tops_snapshot[]; static const fs_operation_def_t zfsctl_tops_shares[]; static vnode_t *zfsctl_mknode_snapdir(vnode_t *); static vnode_t *zfsctl_mknode_shares(vnode_t *); static vnode_t *zfsctl_snapshot_mknode(vnode_t *, uint64_t objset); static int zfsctl_unmount_snap(zfs_snapentry_t *, int, cred_t *); static gfs_opsvec_t zfsctl_opsvec[] = { { ".zfs", zfsctl_tops_root, &zfsctl_ops_root }, { ".zfs/snapshot", zfsctl_tops_snapdir, &zfsctl_ops_snapdir }, { ".zfs/snapshot/vnode", zfsctl_tops_snapshot, &zfsctl_ops_snapshot }, { ".zfs/shares", zfsctl_tops_shares, &zfsctl_ops_shares_dir }, { ".zfs/shares/vnode", zfsctl_tops_shares, &zfsctl_ops_shares }, { NULL } }; /* * Root directory elements. We only have two entries * snapshot and shares. */ static gfs_dirent_t zfsctl_root_entries[] = { { "snapshot", zfsctl_mknode_snapdir, GFS_CACHE_VNODE }, { "shares", zfsctl_mknode_shares, 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) { VERIFY(gfs_make_opsvec(zfsctl_opsvec) == 0); } void zfsctl_fini(void) { /* * Remove vfsctl vnode ops */ if (zfsctl_ops_root) vn_freevnodeops(zfsctl_ops_root); if (zfsctl_ops_snapdir) vn_freevnodeops(zfsctl_ops_snapdir); if (zfsctl_ops_snapshot) vn_freevnodeops(zfsctl_ops_snapshot); if (zfsctl_ops_shares) vn_freevnodeops(zfsctl_ops_shares); if (zfsctl_ops_shares_dir) vn_freevnodeops(zfsctl_ops_shares_dir); zfsctl_ops_root = NULL; zfsctl_ops_snapdir = NULL; zfsctl_ops_snapshot = NULL; zfsctl_ops_shares = NULL; zfsctl_ops_shares_dir = NULL; } boolean_t zfsctl_is_node(vnode_t *vp) { return (vn_matchops(vp, zfsctl_ops_root) || vn_matchops(vp, zfsctl_ops_snapdir) || vn_matchops(vp, zfsctl_ops_snapshot) || vn_matchops(vp, zfsctl_ops_shares) || vn_matchops(vp, zfsctl_ops_shares_dir)); } /* * Return the inode number associated with the 'snapshot' or * 'shares' directory. */ /* ARGSUSED */ static ino64_t zfsctl_root_inode_cb(vnode_t *vp, int index) { zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; ASSERT(index <= 2); if (index == 0) return (ZFSCTL_INO_SNAPDIR); return (zfsvfs->z_shares_dir); } /* * 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; uint64_t crtime[2]; 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, &rvp) == 0); VERIFY(0 == sa_lookup(VTOZ(rvp)->z_sa_hdl, SA_ZPL_CRTIME(zfsvfs), &crtime, sizeof (crtime))); ZFS_TIME_DECODE(&zcp->zc_cmtime, crtime); VN_RELE(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_flag &= ~(VROOT | VNOCACHE | VNOMAP | VNOSWAP | VNOMOUNT); 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(vnode_t **vpp, int flags, cred_t *cr, caller_context_t *ct) { if (flags & FWRITE) return (EACCES); return (0); } /* * Common close routine. Nothing to do here. */ /* ARGSUSED */ static int zfsctl_common_close(vnode_t *vpp, int flags, int count, offset_t off, cred_t *cr, caller_context_t *ct) { return (0); } /* * Common access routine. Disallow writes. */ /* ARGSUSED */ static int zfsctl_common_access(vnode_t *vp, int mode, int flags, cred_t *cr, caller_context_t *ct) { if (flags & V_ACE_MASK) { if (mode & ACE_ALL_WRITE_PERMS) return (EACCES); } else { 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) { timestruc_t now; vap->va_uid = 0; vap->va_gid = 0; vap->va_rdev = 0; /* * We are a purely 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_vfsp->vfs_dev; 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; } /*ARGSUSED*/ static int zfsctl_common_fid(vnode_t *vp, fid_t *fidp, caller_context_t *ct) { 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); if (fidp->fid_len < SHORT_FID_LEN) { fidp->fid_len = SHORT_FID_LEN; ZFS_EXIT(zfsvfs); return (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); return (0); } /*ARGSUSED*/ static int zfsctl_shares_fid(vnode_t *vp, fid_t *fidp, caller_context_t *ct) { zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; znode_t *dzp; int error; ZFS_ENTER(zfsvfs); if (zfsvfs->z_shares_dir == 0) { ZFS_EXIT(zfsvfs); return (ENOTSUP); } if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) { error = VOP_FID(ZTOV(dzp), fidp, ct); VN_RELE(ZTOV(dzp)); } ZFS_EXIT(zfsvfs); return (error); } /* * .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(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr, caller_context_t *ct) { zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; zfsctl_node_t *zcp = vp->v_data; ZFS_ENTER(zfsvfs); vap->va_nodeid = ZFSCTL_INO_ROOT; vap->va_nlink = vap->va_size = NROOT_ENTRIES; vap->va_mtime = vap->va_ctime = zcp->zc_cmtime; 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, caller_context_t *ct, int *direntflags, pathname_t *realpnp) { zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data; int err; /* * No extended attributes allowed under .zfs */ if (flags & LOOKUP_XATTR) return (EINVAL); ZFS_ENTER(zfsvfs); if (strcmp(nm, "..") == 0) { err = VFS_ROOT(dvp->v_vfsp, vpp); } else { err = gfs_vop_lookup(dvp, nm, vpp, pnp, flags, rdir, cr, ct, direntflags, realpnp); } ZFS_EXIT(zfsvfs); return (err); } static int zfsctl_pathconf(vnode_t *vp, int cmd, ulong_t *valp, cred_t *cr, caller_context_t *ct) { /* * We only care about ACL_ENABLED so that libsec can * display ACL correctly and not default to POSIX draft. */ if (cmd == _PC_ACL_ENABLED) { *valp = _ACL_ACE_ENABLED; return (0); } return (fs_pathconf(vp, cmd, valp, cr, ct)); } static const fs_operation_def_t zfsctl_tops_root[] = { { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } }, { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } }, { VOPNAME_IOCTL, { .error = fs_inval } }, { VOPNAME_GETATTR, { .vop_getattr = zfsctl_root_getattr } }, { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } }, { VOPNAME_READDIR, { .vop_readdir = gfs_vop_readdir } }, { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_root_lookup } }, { VOPNAME_SEEK, { .vop_seek = fs_seek } }, { VOPNAME_INACTIVE, { .vop_inactive = gfs_vop_inactive } }, { VOPNAME_PATHCONF, { .vop_pathconf = zfsctl_pathconf } }, { VOPNAME_FID, { .vop_fid = zfsctl_common_fid } }, { NULL } }; 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; if (snapshot_namecheck(name, NULL, NULL) != 0) return (EILSEQ); 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(zfs_snapentry_t *sep, int fflags, cred_t *cr) { vnode_t *svp = sep->se_root; int error; ASSERT(vn_ismntpt(svp)); /* this will be dropped by dounmount() */ if ((error = vn_vfswlock(svp)) != 0) return (error); VN_HOLD(svp); error = dounmount(vn_mountedvfs(svp), fflags, cr); if (error) { VN_RELE(svp); return (error); } /* * We can't use VN_RELE(), as that will try to invoke * zfsctl_snapdir_inactive(), which would cause us to destroy * the sd_lock mutex held by our caller. */ ASSERT(svp->v_count == 1); gfs_vop_inactive(svp, cr, NULL); kmem_free(sep->se_name, strlen(sep->se_name) + 1); kmem_free(sep, sizeof (zfs_snapentry_t)); return (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); } /*ARGSUSED*/ static int zfsctl_snapdir_rename(vnode_t *sdvp, char *snm, vnode_t *tdvp, char *tnm, cred_t *cr, caller_context_t *ct, int flags) { zfsctl_snapdir_t *sdp = sdvp->v_data; zfs_snapentry_t search, *sep; zfsvfs_t *zfsvfs; avl_index_t where; char from[MAXNAMELEN], to[MAXNAMELEN]; char real[MAXNAMELEN]; int err; zfsvfs = sdvp->v_vfsp->vfs_data; ZFS_ENTER(zfsvfs); if ((flags & FIGNORECASE) || zfsvfs->z_case == ZFS_CASE_INSENSITIVE) { err = dmu_snapshot_realname(zfsvfs->z_os, snm, real, MAXNAMELEN, NULL); if (err == 0) { snm = real; } else if (err != ENOTSUP) { ZFS_EXIT(zfsvfs); return (err); } } ZFS_EXIT(zfsvfs); err = zfsctl_snapshot_zname(sdvp, snm, MAXNAMELEN, from); if (!err) err = zfsctl_snapshot_zname(tdvp, tnm, MAXNAMELEN, to); if (!err) err = zfs_secpolicy_rename_perms(from, to, cr); if (err) return (err); /* * Cannot move snapshots out of the snapdir. */ if (sdvp != tdvp) return (EINVAL); if (strcmp(snm, tnm) == 0) return (0); 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, B_FALSE); if (err == 0) zfsctl_rename_snap(sdp, sep, tnm); mutex_exit(&sdp->sd_lock); return (err); } /* ARGSUSED */ static int zfsctl_snapdir_remove(vnode_t *dvp, char *name, vnode_t *cwd, cred_t *cr, caller_context_t *ct, int flags) { zfsctl_snapdir_t *sdp = dvp->v_data; zfs_snapentry_t *sep; zfs_snapentry_t search; zfsvfs_t *zfsvfs; char snapname[MAXNAMELEN]; char real[MAXNAMELEN]; int err; zfsvfs = dvp->v_vfsp->vfs_data; ZFS_ENTER(zfsvfs); if ((flags & FIGNORECASE) || zfsvfs->z_case == ZFS_CASE_INSENSITIVE) { err = dmu_snapshot_realname(zfsvfs->z_os, name, real, MAXNAMELEN, NULL); if (err == 0) { name = real; } else if (err != ENOTSUP) { ZFS_EXIT(zfsvfs); return (err); } } ZFS_EXIT(zfsvfs); err = zfsctl_snapshot_zname(dvp, name, MAXNAMELEN, snapname); if (!err) err = zfs_secpolicy_destroy_perms(snapname, cr); if (err) return (err); mutex_enter(&sdp->sd_lock); search.se_name = name; sep = avl_find(&sdp->sd_snaps, &search, NULL); if (sep) { avl_remove(&sdp->sd_snaps, sep); err = zfsctl_unmount_snap(sep, MS_FORCE, cr); if (err) avl_add(&sdp->sd_snaps, sep); else err = dmu_objset_destroy(snapname, B_FALSE); } else { err = ENOENT; } mutex_exit(&sdp->sd_lock); return (err); } /* * This creates a snapshot under '.zfs/snapshot'. */ /* ARGSUSED */ static int zfsctl_snapdir_mkdir(vnode_t *dvp, char *dirname, vattr_t *vap, vnode_t **vpp, cred_t *cr, caller_context_t *cc, int flags, vsecattr_t *vsecp) { zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data; char name[MAXNAMELEN]; int err; static enum symfollow follow = NO_FOLLOW; static enum uio_seg seg = UIO_SYSSPACE; if (snapshot_namecheck(dirname, NULL, NULL) != 0) return (EILSEQ); dmu_objset_name(zfsvfs->z_os, name); *vpp = NULL; err = zfs_secpolicy_snapshot_perms(name, cr); if (err) return (err); if (err == 0) { err = dmu_objset_snapshot(name, dirname, NULL, B_FALSE); if (err) return (err); err = lookupnameat(dirname, seg, follow, NULL, vpp, dvp); } return (err); } /* * 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 */ static int zfsctl_snapdir_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp, int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct, int *direntflags, pathname_t *realpnp) { zfsctl_snapdir_t *sdp = dvp->v_data; objset_t *snap; char snapname[MAXNAMELEN]; char real[MAXNAMELEN]; char *mountpoint; zfs_snapentry_t *sep, search; struct mounta margs; vfs_t *vfsp; size_t mountpoint_len; avl_index_t where; zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data; int err; /* * No extended attributes allowed under .zfs */ if (flags & LOOKUP_XATTR) return (EINVAL); ASSERT(dvp->v_type == VDIR); /* * 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); if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) { ZFS_EXIT(zfsvfs); return (0); } if (flags & FIGNORECASE) { boolean_t conflict = B_FALSE; err = dmu_snapshot_realname(zfsvfs->z_os, nm, real, MAXNAMELEN, &conflict); if (err == 0) { nm = real; } else if (err != ENOTSUP) { ZFS_EXIT(zfsvfs); return (err); } if (realpnp) (void) strlcpy(realpnp->pn_buf, nm, realpnp->pn_bufsize); if (conflict && direntflags) *direntflags = ED_CASE_CONFLICT; } 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); err = traverse(vpp); if (err) { VN_RELE(*vpp); *vpp = NULL; } else if (*vpp == sep->se_root) { /* * The snapshot was unmounted behind our backs, * try to remount it. */ goto domount; } else { /* * VROOT was set during the traverse call. We need * to clear it since we're pretending to be part * of our parent's vfs. */ (*vpp)->v_flag &= ~VROOT; } mutex_exit(&sdp->sd_lock); ZFS_EXIT(zfsvfs); return (err); } /* * 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); /* * handle "ls *" or "?" in a graceful manner, * forcing EILSEQ to ENOENT. * Since shell ultimately passes "*" or "?" as name to lookup */ return (err == EILSEQ ? ENOENT : err); } if (dmu_objset_hold(snapname, FTAG, &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)); avl_insert(&sdp->sd_snaps, sep, where); dmu_objset_rele(snap, FTAG); domount: mountpoint_len = strlen(refstr_value(dvp->v_vfsp->vfs_mntpt)) + strlen("/.zfs/snapshot/") + strlen(nm) + 1; mountpoint = kmem_alloc(mountpoint_len, KM_SLEEP); (void) snprintf(mountpoint, mountpoint_len, "%s/.zfs/snapshot/%s", refstr_value(dvp->v_vfsp->vfs_mntpt), nm); margs.spec = snapname; margs.dir = mountpoint; margs.flags = MS_SYSSPACE | MS_NOMNTTAB; margs.fstype = "zfs"; margs.dataptr = NULL; margs.datalen = 0; margs.optptr = NULL; margs.optlen = 0; err = domount("zfs", &margs, *vpp, kcred, &vfsp); kmem_free(mountpoint, mountpoint_len); if (err == 0) { /* * Return the mounted root rather than the covered mount point. * Takes the GFS vnode at .zfs/snapshot/<snapname> and returns * the ZFS vnode mounted on top of the GFS node. This ZFS * vnode is the root of the newly created vfsp. */ VFS_RELE(vfsp); err = traverse(vpp); } if (err == 0) { /* * Fix up the root vnode mounted on .zfs/snapshot/<snapname>. * * This is where we lie about our v_vfsp in order to * make .zfs/snapshot/<snapname> accessible over NFS * without requiring manual mounts of <snapname>. */ ASSERT(VTOZ(*vpp)->z_zfsvfs != zfsvfs); VTOZ(*vpp)->z_zfsvfs->z_parent = zfsvfs; (*vpp)->v_vfsp = zfsvfs->z_vfs; (*vpp)->v_flag &= ~VROOT; } mutex_exit(&sdp->sd_lock); ZFS_EXIT(zfsvfs); /* * 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_shares_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp, int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct, int *direntflags, pathname_t *realpnp) { zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data; znode_t *dzp; int error; ZFS_ENTER(zfsvfs); if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) { ZFS_EXIT(zfsvfs); return (0); } if (zfsvfs->z_shares_dir == 0) { ZFS_EXIT(zfsvfs); return (ENOTSUP); } if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) error = VOP_LOOKUP(ZTOV(dzp), nm, vpp, pnp, flags, rdir, cr, ct, direntflags, realpnp); VN_RELE(ZTOV(dzp)); ZFS_EXIT(zfsvfs); return (error); } /* ARGSUSED */ static int zfsctl_snapdir_readdir_cb(vnode_t *vp, void *dp, int *eofp, offset_t *offp, offset_t *nextp, void *data, int flags) { zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; char snapname[MAXNAMELEN]; uint64_t id, cookie; boolean_t case_conflict; int error; ZFS_ENTER(zfsvfs); cookie = *offp; error = dmu_snapshot_list_next(zfsvfs->z_os, MAXNAMELEN, snapname, &id, &cookie, &case_conflict); if (error) { ZFS_EXIT(zfsvfs); if (error == ENOENT) { *eofp = 1; return (0); } return (error); } if (flags & V_RDDIR_ENTFLAGS) { edirent_t *eodp = dp; (void) strcpy(eodp->ed_name, snapname); eodp->ed_ino = ZFSCTL_INO_SNAP(id); eodp->ed_eflags = case_conflict ? ED_CASE_CONFLICT : 0; } else { struct dirent64 *odp = dp; (void) strcpy(odp->d_name, snapname); odp->d_ino = ZFSCTL_INO_SNAP(id); } *nextp = cookie; ZFS_EXIT(zfsvfs); return (0); } /* ARGSUSED */ static int zfsctl_shares_readdir(vnode_t *vp, uio_t *uiop, cred_t *cr, int *eofp, caller_context_t *ct, int flags) { zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; znode_t *dzp; int error; ZFS_ENTER(zfsvfs); if (zfsvfs->z_shares_dir == 0) { ZFS_EXIT(zfsvfs); return (ENOTSUP); } if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) { error = VOP_READDIR(ZTOV(dzp), uiop, cr, eofp, ct, flags); VN_RELE(ZTOV(dzp)); } else { *eofp = 1; error = ENOENT; } ZFS_EXIT(zfsvfs); return (error); } /* * pvp is the '.zfs' directory (zfsctl_node_t). * Creates vp, which is '.zfs/snapshot' (zfsctl_snapdir_t). * * This function is the callback to create a GFS vnode for '.zfs/snapshot' * when a lookup is performed on .zfs for "snapshot". */ vnode_t * zfsctl_mknode_snapdir(vnode_t *pvp) { vnode_t *vp; zfsctl_snapdir_t *sdp; vp = gfs_dir_create(sizeof (zfsctl_snapdir_t), pvp, 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); } vnode_t * zfsctl_mknode_shares(vnode_t *pvp) { vnode_t *vp; zfsctl_node_t *sdp; vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp, zfsctl_ops_shares, NULL, NULL, MAXNAMELEN, NULL, NULL); sdp = vp->v_data; sdp->zc_cmtime = ((zfsctl_node_t *)pvp->v_data)->zc_cmtime; return (vp); } /* ARGSUSED */ static int zfsctl_shares_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr, caller_context_t *ct) { zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data; znode_t *dzp; int error; ZFS_ENTER(zfsvfs); if (zfsvfs->z_shares_dir == 0) { ZFS_EXIT(zfsvfs); return (ENOTSUP); } if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) { error = VOP_GETATTR(ZTOV(dzp), vap, flags, cr, ct); VN_RELE(ZTOV(dzp)); } ZFS_EXIT(zfsvfs); return (error); } /* ARGSUSED */ static int zfsctl_snapdir_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr, caller_context_t *ct) { 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; vap->va_ctime = vap->va_mtime = dmu_objset_snap_cmtime(zfsvfs->z_os); ZFS_EXIT(zfsvfs); return (0); } /* ARGSUSED */ static void zfsctl_snapdir_inactive(vnode_t *vp, cred_t *cr, caller_context_t *ct) { 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)); } } static const fs_operation_def_t zfsctl_tops_snapdir[] = { { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } }, { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } }, { VOPNAME_IOCTL, { .error = fs_inval } }, { VOPNAME_GETATTR, { .vop_getattr = zfsctl_snapdir_getattr } }, { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } }, { VOPNAME_RENAME, { .vop_rename = zfsctl_snapdir_rename } }, { VOPNAME_RMDIR, { .vop_rmdir = zfsctl_snapdir_remove } }, { VOPNAME_MKDIR, { .vop_mkdir = zfsctl_snapdir_mkdir } }, { VOPNAME_READDIR, { .vop_readdir = gfs_vop_readdir } }, { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_snapdir_lookup } }, { VOPNAME_SEEK, { .vop_seek = fs_seek } }, { VOPNAME_INACTIVE, { .vop_inactive = zfsctl_snapdir_inactive } }, { VOPNAME_FID, { .vop_fid = zfsctl_common_fid } }, { NULL } }; static const fs_operation_def_t zfsctl_tops_shares[] = { { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } }, { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } }, { VOPNAME_IOCTL, { .error = fs_inval } }, { VOPNAME_GETATTR, { .vop_getattr = zfsctl_shares_getattr } }, { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } }, { VOPNAME_READDIR, { .vop_readdir = zfsctl_shares_readdir } }, { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_shares_lookup } }, { VOPNAME_SEEK, { .vop_seek = fs_seek } }, { VOPNAME_INACTIVE, { .vop_inactive = gfs_vop_inactive } }, { VOPNAME_FID, { .vop_fid = zfsctl_shares_fid } }, { NULL } }; /* * pvp is the GFS vnode '.zfs/snapshot'. * * This creates a GFS node under '.zfs/snapshot' representing each * snapshot. This newly created GFS node is what we mount snapshot * vfs_t's ontop of. */ 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, zfsctl_ops_snapshot, NULL, NULL, MAXNAMELEN, NULL, NULL); zcp = vp->v_data; zcp->zc_id = objset; return (vp); } static void zfsctl_snapshot_inactive(vnode_t *vp, cred_t *cr, caller_context_t *ct) { zfsctl_snapdir_t *sdp; zfs_snapentry_t *sep, *next; vnode_t *dvp; VERIFY(gfs_dir_lookup(vp, "..", &dvp, cr, 0, NULL, NULL) == 0); sdp = dvp->v_data; mutex_enter(&sdp->sd_lock); if (vp->v_count > 1) { mutex_exit(&sdp->sd_lock); return; } 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); 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. */ gfs_vop_inactive(vp, cr, ct); } /* * These VP's should never see the light of day. They should always * be covered. */ static const fs_operation_def_t zfsctl_tops_snapshot[] = { VOPNAME_INACTIVE, { .vop_inactive = zfsctl_snapshot_inactive }, NULL, NULL }; 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, NULL, NULL, NULL); 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); /* * Return the mounted root rather than the covered mount point. * Takes the GFS vnode at .zfs/snapshot/<snapshot objsetid> * and returns the ZFS vnode mounted on top of the GFS node. * This ZFS vnode is the root of the vfs for objset 'objsetid'. */ 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) { zfsvfs_t *zfsvfs = vfsp->vfs_data; vnode_t *dvp; 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, NULL, NULL, NULL); if (error != 0) return (error); sdp = dvp->v_data; mutex_enter(&sdp->sd_lock); sep = avl_first(&sdp->sd_snaps); while (sep != NULL) { 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(sep->se_root)) { avl_remove(&sdp->sd_snaps, sep); error = zfsctl_unmount_snap(sep, fflags, cr); if (error) { avl_add(&sdp->sd_snaps, sep); break; } } sep = next; } mutex_exit(&sdp->sd_lock); VN_RELE(dvp); return (error); }