diff options
Diffstat (limited to 'module/os/freebsd/spl/spl_vfs.c')
| -rw-r--r-- | module/os/freebsd/spl/spl_vfs.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/module/os/freebsd/spl/spl_vfs.c b/module/os/freebsd/spl/spl_vfs.c new file mode 100644 index 000000000000..991a11fe2baf --- /dev/null +++ b/module/os/freebsd/spl/spl_vfs.c @@ -0,0 +1,285 @@ +/* + * Copyright (c) 2006-2007 Pawel Jakub Dawidek <pjd@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/types.h> +#include <sys/param.h> +#include <sys/kernel.h> +#include <sys/systm.h> +#include <sys/malloc.h> +#include <sys/mount.h> +#include <sys/cred.h> +#include <sys/vfs.h> +#include <sys/priv.h> +#include <sys/libkern.h> + +#include <sys/mutex.h> +#include <sys/vnode.h> +#include <sys/taskq.h> + +#include <sys/ccompat.h> + +MALLOC_DECLARE(M_MOUNT); + +void +vfs_setmntopt(vfs_t *vfsp, const char *name, const char *arg, + int flags __unused) +{ + struct vfsopt *opt; + size_t namesize; + int locked; + + if (!(locked = mtx_owned(MNT_MTX(vfsp)))) + MNT_ILOCK(vfsp); + + if (vfsp->mnt_opt == NULL) { + void *opts; + + MNT_IUNLOCK(vfsp); + opts = malloc(sizeof (*vfsp->mnt_opt), M_MOUNT, M_WAITOK); + MNT_ILOCK(vfsp); + if (vfsp->mnt_opt == NULL) { + vfsp->mnt_opt = opts; + TAILQ_INIT(vfsp->mnt_opt); + } else { + free(opts, M_MOUNT); + } + } + + MNT_IUNLOCK(vfsp); + + opt = malloc(sizeof (*opt), M_MOUNT, M_WAITOK); + namesize = strlen(name) + 1; + opt->name = malloc(namesize, M_MOUNT, M_WAITOK); + strlcpy(opt->name, name, namesize); + opt->pos = -1; + opt->seen = 1; + if (arg == NULL) { + opt->value = NULL; + opt->len = 0; + } else { + opt->len = strlen(arg) + 1; + opt->value = malloc(opt->len, M_MOUNT, M_WAITOK); + bcopy(arg, opt->value, opt->len); + } + + MNT_ILOCK(vfsp); + TAILQ_INSERT_TAIL(vfsp->mnt_opt, opt, link); + if (!locked) + MNT_IUNLOCK(vfsp); +} + +void +vfs_clearmntopt(vfs_t *vfsp, const char *name) +{ + int locked; + + if (!(locked = mtx_owned(MNT_MTX(vfsp)))) + MNT_ILOCK(vfsp); + vfs_deleteopt(vfsp->mnt_opt, name); + if (!locked) + MNT_IUNLOCK(vfsp); +} + +int +vfs_optionisset(const vfs_t *vfsp, const char *opt, char **argp) +{ + struct vfsoptlist *opts = vfsp->mnt_optnew; + int error; + + if (opts == NULL) + return (0); + error = vfs_getopt(opts, opt, (void **)argp, NULL); + return (error != 0 ? 0 : 1); +} + +int +mount_snapshot(kthread_t *td, vnode_t **vpp, const char *fstype, char *fspath, + char *fspec, int fsflags) +{ + struct vfsconf *vfsp; + struct mount *mp; + vnode_t *vp, *mvp; + struct ucred *cr; + int error; + + ASSERT_VOP_ELOCKED(*vpp, "mount_snapshot"); + + vp = *vpp; + *vpp = NULL; + error = 0; + + /* + * Be ultra-paranoid about making sure the type and fspath + * variables will fit in our mp buffers, including the + * terminating NUL. + */ + if (strlen(fstype) >= MFSNAMELEN || strlen(fspath) >= MNAMELEN) + error = ENAMETOOLONG; + if (error == 0 && (vfsp = vfs_byname_kld(fstype, td, &error)) == NULL) + error = ENODEV; + if (error == 0 && vp->v_type != VDIR) + error = ENOTDIR; + /* + * We need vnode lock to protect v_mountedhere and vnode interlock + * to protect v_iflag. + */ + if (error == 0) { + VI_LOCK(vp); + if ((vp->v_iflag & VI_MOUNT) == 0 && vp->v_mountedhere == NULL) + vp->v_iflag |= VI_MOUNT; + else + error = EBUSY; + VI_UNLOCK(vp); + } + if (error != 0) { + vput(vp); + return (error); + } + vn_seqc_write_begin(vp); + VOP_UNLOCK1(vp); + + /* + * Allocate and initialize the filesystem. + * We don't want regular user that triggered snapshot mount to be able + * to unmount it, so pass credentials of the parent mount. + */ + mp = vfs_mount_alloc(vp, vfsp, fspath, vp->v_mount->mnt_cred); + + mp->mnt_optnew = NULL; + vfs_setmntopt(mp, "from", fspec, 0); + mp->mnt_optnew = mp->mnt_opt; + mp->mnt_opt = NULL; + + /* + * Set the mount level flags. + */ + mp->mnt_flag = fsflags & MNT_UPDATEMASK; + /* + * Snapshots are always read-only. + */ + mp->mnt_flag |= MNT_RDONLY; + /* + * We don't want snapshots to allow access to vulnerable setuid + * programs, so we turn off setuid when mounting snapshots. + */ + mp->mnt_flag |= MNT_NOSUID; + /* + * We don't want snapshots to be visible in regular + * mount(8) and df(1) output. + */ + mp->mnt_flag |= MNT_IGNORE; + /* + * XXX: This is evil, but we can't mount a snapshot as a regular user. + * XXX: Is is safe when snapshot is mounted from within a jail? + */ + cr = td->td_ucred; + td->td_ucred = kcred; + error = VFS_MOUNT(mp); + td->td_ucred = cr; + + if (error != 0) { + /* + * Clear VI_MOUNT and decrement the use count "atomically", + * under the vnode lock. This is not strictly required, + * but makes it easier to reason about the life-cycle and + * ownership of the covered vnode. + */ + vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); + VI_LOCK(vp); + vp->v_iflag &= ~VI_MOUNT; + VI_UNLOCK(vp); + vn_seqc_write_end(vp); + vput(vp); + vfs_unbusy(mp); + vfs_freeopts(mp->mnt_optnew); + mp->mnt_vnodecovered = NULL; + vfs_mount_destroy(mp); + return (error); + } + + if (mp->mnt_opt != NULL) + vfs_freeopts(mp->mnt_opt); + mp->mnt_opt = mp->mnt_optnew; + (void) VFS_STATFS(mp, &mp->mnt_stat); + + /* + * Prevent external consumers of mount options from reading + * mnt_optnew. + */ + mp->mnt_optnew = NULL; + + vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); +#ifdef FREEBSD_NAMECACHE + cache_purge(vp); +#endif + VI_LOCK(vp); + vp->v_iflag &= ~VI_MOUNT; + VI_UNLOCK(vp); + + vp->v_mountedhere = mp; + /* Put the new filesystem on the mount list. */ + mtx_lock(&mountlist_mtx); + TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list); + mtx_unlock(&mountlist_mtx); + vfs_event_signal(NULL, VQ_MOUNT, 0); + if (VFS_ROOT(mp, LK_EXCLUSIVE, &mvp)) + panic("mount: lost mount"); + vn_seqc_write_end(vp); + VOP_UNLOCK1(vp); +#if __FreeBSD_version >= 1300048 + vfs_op_exit(mp); +#endif + vfs_unbusy(mp); + *vpp = mvp; + return (0); +} + +/* + * Like vn_rele() except if we are going to call VOP_INACTIVE() then do it + * asynchronously using a taskq. This can avoid deadlocks caused by re-entering + * the file system as a result of releasing the vnode. Note, file systems + * already have to handle the race where the vnode is incremented before the + * inactive routine is called and does its locking. + * + * Warning: Excessive use of this routine can lead to performance problems. + * This is because taskqs throttle back allocation if too many are created. + */ +void +vn_rele_async(vnode_t *vp, taskq_t *taskq) +{ + VERIFY(vp->v_count > 0); + if (refcount_release_if_not_last(&vp->v_usecount)) { +#if __FreeBSD_version < 1300045 + vdrop(vp); +#endif + return; + } + VERIFY(taskq_dispatch((taskq_t *)taskq, + (task_func_t *)vrele, vp, TQ_SLEEP) != 0); +} |