diff --git a/include/sys/zfs_ctldir.h b/include/sys/zfs_ctldir.h index 26f0122ff..fb85b17f5 100644 --- a/include/sys/zfs_ctldir.h +++ b/include/sys/zfs_ctldir.h @@ -78,8 +78,8 @@ extern int zfsctl_snapshot_mount(struct path *path, int flags); extern int zfsctl_snapshot_unmount(char *snapname, int flags); extern int zfsctl_snapshot_unmount_delay(spa_t *spa, uint64_t objsetid, int delay); -extern int zfsctl_lookup_objset(struct super_block *sb, uint64_t objsetid, - zfs_sb_t **zsb); +extern int zfsctl_snapdir_vget(struct super_block *sb, uint64_t objsetid, + int gen, struct inode **ipp); /* zfsctl '.zfs/shares' functions */ extern int zfsctl_shares_lookup(struct inode *dip, char *name, diff --git a/lib/libshare/nfs.c b/lib/libshare/nfs.c index 99dd7c1c4..0cfd42c1a 100644 --- a/lib/libshare/nfs.c +++ b/lib/libshare/nfs.c @@ -600,7 +600,7 @@ nfs_update_shareopts(sa_share_impl_t impl_share, const char *resource, old_shareopts = FSINFO(impl_share, nfs_fstype)->shareopts; if (strcmp(shareopts, "on") == 0) - shareopts = "rw"; + shareopts = "rw,crossmnt"; if (FSINFO(impl_share, nfs_fstype)->active && old_shareopts != NULL && strcmp(old_shareopts, shareopts) != 0) { diff --git a/man/man8/zfs.8 b/man/man8/zfs.8 index 0f9a631d9..888a5f8eb 100644 --- a/man/man8/zfs.8 +++ b/man/man8/zfs.8 @@ -1340,7 +1340,7 @@ Controls whether the file system is shared via \fBNFS\fR, and what options are u .sp .in +4 .nf -/usr/sbin/exportfs -i -o sec=sys,rw,no_subtree_check,no_root_squash,mountpoint *: +/usr/sbin/exportfs -i -o sec=sys,rw,crossmnt,no_subtree_check,no_root_squash,mountpoint *: .fi .in -4 .sp @@ -3746,6 +3746,10 @@ The following commands show how to set \fBsharenfs\fR property options to enable .LP If you are using \fBDNS\fR for host name resolution, specify the fully qualified hostname. +.sp +.LP +If you want to access snapdir through NFS, be sure to add \fBcrossmnt\fR to the options. + .LP \fBExample 17 \fRDelegating ZFS Administration Permissions on a ZFS Dataset .sp diff --git a/module/zfs/zfs_ctldir.c b/module/zfs/zfs_ctldir.c index e340462fb..8847db7f1 100644 --- a/module/zfs/zfs_ctldir.c +++ b/module/zfs/zfs_ctldir.c @@ -590,27 +590,40 @@ zfsctl_root(znode_t *zp) igrab(ZTOZSB(zp)->z_ctldir); return (ZTOZSB(zp)->z_ctldir); } + /* - * Generate a long fid which includes the root object and objset of a - * snapshot but not the generation number. For the root object the - * generation number is ignored when zero to avoid needing to open - * the dataset when generating fids for the snapshot names. + * Generate a long fid to indicate a snapdir. We encode whether snapdir is + * already monunted in gen field. We do this because nfsd lookup will not + * trigger automount. Next time the nfsd does fh_to_dentry, we will notice + * this and do automount and return ESTALE to force nfsd revalidate and follow + * mount. */ static int zfsctl_snapdir_fid(struct inode *ip, fid_t *fidp) { - zfs_sb_t *zsb = ITOZSB(ip); zfid_short_t *zfid = (zfid_short_t *)fidp; zfid_long_t *zlfid = (zfid_long_t *)fidp; uint32_t gen = 0; uint64_t object; uint64_t objsetid; int i; + struct dentry *dentry; - object = zsb->z_root; + 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)); @@ -640,17 +653,17 @@ zfsctl_fid(struct inode *ip, fid_t *fidp) ZFS_ENTER(zsb); + if (zfsctl_is_snapdir(ip)) { + ZFS_EXIT(zsb); + return (zfsctl_snapdir_fid(ip, fidp)); + } + if (fidp->fid_len < SHORT_FID_LEN) { fidp->fid_len = SHORT_FID_LEN; ZFS_EXIT(zsb); return (SET_ERROR(ENOSPC)); } - if (zfsctl_is_snapdir(ip)) { - ZFS_EXIT(zsb); - return (zfsctl_snapdir_fid(ip, fidp)); - } - zfid = (zfid_short_t *)fidp; zfid->zf_len = SHORT_FID_LEN; @@ -1145,70 +1158,52 @@ error: } /* - * Given the objset id of the snapshot return its zfs_sb_t as zsbp. + * Get the snapdir inode from fid */ int -zfsctl_lookup_objset(struct super_block *sb, uint64_t objsetid, zfs_sb_t **zsbp) +zfsctl_snapdir_vget(struct super_block *sb, uint64_t objsetid, int gen, + struct inode **ipp) { - zfs_snapentry_t *se; int error; - spa_t *spa = ((zfs_sb_t *)(sb->s_fs_info))->z_os->os_spa; + struct path path; + char *mnt; + struct dentry *dentry; + mnt = kmem_alloc(MAXPATHLEN, KM_SLEEP); + + error = zfsctl_snapshot_path_objset(sb->s_fs_info, objsetid, + MAXPATHLEN, mnt); + if (error) + goto out; + + /* Trigger automount */ + error = kern_path(mnt, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &path); + if (error) + goto out; + + path_put(&path); /* - * Verify that the snapshot is mounted then lookup the mounted root - * rather than the covered mount point. This may fail if the - * snapshot has just been unmounted by an unrelated user space - * process. This race cannot occur to an expired mount point - * because we hold the zfs_snapshot_lock to prevent the race. + * Get the snapdir inode. Note, we don't want to use the above + * path because it contains the root of the snapshot rather + * than the snapdir. */ - rw_enter(&zfs_snapshot_lock, RW_READER); - if ((se = zfsctl_snapshot_find_by_objsetid(spa, objsetid)) != NULL) { - zfs_sb_t *zsb; + *ipp = ilookup(sb, ZFSCTL_INO_SNAPDIRS - objsetid); + if (*ipp == NULL) { + error = SET_ERROR(ENOENT); + goto out; + } - zsb = ITOZSB(se->se_root_dentry->d_inode); - ASSERT3U(dmu_objset_id(zsb->z_os), ==, objsetid); - - if (time_after(jiffies, zsb->z_snap_defer_time + - MAX(zfs_expire_snapshot * HZ / 2, HZ))) { - zsb->z_snap_defer_time = jiffies; - zfsctl_snapshot_unmount_cancel(se); - zfsctl_snapshot_unmount_delay_impl(se, - zfs_expire_snapshot); - } - - *zsbp = zsb; - zfsctl_snapshot_rele(se); - error = SET_ERROR(0); - } else { + /* check gen, see zfsctl_snapdir_fid */ + dentry = d_obtain_alias(igrab(*ipp)); + if (gen != (!IS_ERR(dentry) && d_mountpoint(dentry))) { + iput(*ipp); + *ipp = NULL; error = SET_ERROR(ENOENT); } - rw_exit(&zfs_snapshot_lock); - - /* - * Automount the snapshot given the objset id by constructing the - * full mount point and performing a traversal. - */ - if (error == ENOENT) { - struct path path; - char *mnt; - - mnt = kmem_alloc(MAXPATHLEN, KM_SLEEP); - error = zfsctl_snapshot_path_objset(sb->s_fs_info, objsetid, - MAXPATHLEN, mnt); - if (error) { - kmem_free(mnt, MAXPATHLEN); - return (SET_ERROR(error)); - } - - error = kern_path(mnt, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &path); - if (error == 0) { - *zsbp = ITOZSB(path.dentry->d_inode); - path_put(&path); - } - - kmem_free(mnt, MAXPATHLEN); - } - + if (!IS_ERR(dentry)) + dput(dentry); +out: + kmem_free(mnt, MAXPATHLEN); return (error); } diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c index 85c275822..3135319cb 100644 --- a/module/zfs/zfs_vfsops.c +++ b/module/zfs/zfs_vfsops.c @@ -1597,8 +1597,19 @@ zfs_vget(struct super_block *sb, struct inode **ipp, fid_t *fidp) *ipp = NULL; - ZFS_ENTER(zsb); + if (fidp->fid_len == SHORT_FID_LEN || fidp->fid_len == LONG_FID_LEN) { + zfid_short_t *zfid = (zfid_short_t *)fidp; + for (i = 0; i < sizeof (zfid->zf_object); i++) + object |= ((uint64_t)zfid->zf_object[i]) << (8 * i); + + for (i = 0; i < sizeof (zfid->zf_gen); i++) + fid_gen |= ((uint64_t)zfid->zf_gen[i]) << (8 * i); + } else { + return (SET_ERROR(EINVAL)); + } + + /* LONG_FID_LEN means snapdirs */ if (fidp->fid_len == LONG_FID_LEN) { zfid_long_t *zlfid = (zfid_long_t *)fidp; uint64_t objsetid = 0; @@ -1610,28 +1621,24 @@ zfs_vget(struct super_block *sb, struct inode **ipp, fid_t *fidp) for (i = 0; i < sizeof (zlfid->zf_setgen); i++) setgen |= ((uint64_t)zlfid->zf_setgen[i]) << (8 * i); - ZFS_EXIT(zsb); + if (objsetid != ZFSCTL_INO_SNAPDIRS - object) { + dprintf("snapdir fid: objsetid (%llu) != " + "ZFSCTL_INO_SNAPDIRS (%llu) - object (%llu)\n", + objsetid, ZFSCTL_INO_SNAPDIRS, object); - err = zfsctl_lookup_objset(sb, objsetid, &zsb); - if (err) return (SET_ERROR(EINVAL)); + } - ZFS_ENTER(zsb); - } - - if (fidp->fid_len == SHORT_FID_LEN || fidp->fid_len == LONG_FID_LEN) { - zfid_short_t *zfid = (zfid_short_t *)fidp; - - for (i = 0; i < sizeof (zfid->zf_object); i++) - object |= ((uint64_t)zfid->zf_object[i]) << (8 * i); - - for (i = 0; i < sizeof (zfid->zf_gen); i++) - fid_gen |= ((uint64_t)zfid->zf_gen[i]) << (8 * i); - } else { - ZFS_EXIT(zsb); - return (SET_ERROR(EINVAL)); + if (fid_gen > 1 || setgen != 0) { + dprintf("snapdir fid: fid_gen (%llu) and setgen " + "(%llu)\n", fid_gen, setgen); + return (SET_ERROR(EINVAL)); + } + + return (zfsctl_snapdir_vget(sb, objsetid, fid_gen, ipp)); } + ZFS_ENTER(zsb); /* A zero fid_gen means we are in the .zfs control directories */ if (fid_gen == 0 && (object == ZFSCTL_INO_ROOT || object == ZFSCTL_INO_SNAPDIR)) { diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c index 41572d34f..2e5099574 100644 --- a/module/zfs/zfs_vnops.c +++ b/module/zfs/zfs_vnops.c @@ -4714,12 +4714,7 @@ zfs_fid(struct inode *ip, fid_t *fidp) gen = (uint32_t)gen64; - size = (zsb->z_parent != zsb) ? LONG_FID_LEN : SHORT_FID_LEN; - if (fidp->fid_len < size) { - fidp->fid_len = size; - ZFS_EXIT(zsb); - return (SET_ERROR(ENOSPC)); - } + size = SHORT_FID_LEN; zfid = (zfid_short_t *)fidp; @@ -4734,20 +4729,6 @@ zfs_fid(struct inode *ip, fid_t *fidp) for (i = 0; i < sizeof (zfid->zf_gen); i++) zfid->zf_gen[i] = (uint8_t)(gen >> (8 * i)); - if (size == LONG_FID_LEN) { - uint64_t objsetid = dmu_objset_id(zsb->z_os); - zfid_long_t *zlfid; - - zlfid = (zfid_long_t *)fidp; - - for (i = 0; i < sizeof (zlfid->zf_setid); i++) - zlfid->zf_setid[i] = (uint8_t)(objsetid >> (8 * i)); - - /* XXX - this should be the generation number for the objset */ - for (i = 0; i < sizeof (zlfid->zf_setgen); i++) - zlfid->zf_setgen[i] = 0; - } - ZFS_EXIT(zsb); return (0); }