diff options
Diffstat (limited to 'sys/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c')
| -rw-r--r-- | sys/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c | 796 |
1 files changed, 796 insertions, 0 deletions
diff --git a/sys/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c b/sys/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c new file mode 100644 index 000000000000..486aa74bbc44 --- /dev/null +++ b/sys/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c @@ -0,0 +1,796 @@ +/* + * 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" + +#include <sys/types.h> +#include <sys/param.h> +#include <sys/time.h> +#include <sys/systm.h> +#include <sys/sysmacros.h> +#include <sys/resource.h> +#include <sys/vfs.h> +#include <sys/vnode.h> +#include <sys/file.h> +#include <sys/kmem.h> +#include <sys/uio.h> +#include <sys/cmn_err.h> +#include <sys/errno.h> +#include <sys/stat.h> +#include <sys/unistd.h> +#include <sys/random.h> +#include <sys/kcondvar.h> +#include <sys/callb.h> +#include <sys/smp.h> +#include <sys/zfs_dir.h> +#include <sys/zfs_acl.h> +#include <sys/fs/zfs.h> +#include <sys/zap.h> +#include <sys/dmu.h> +#include <sys/atomic.h> +#include <sys/zfs_ctldir.h> +#include <sys/dnlc.h> + +/* + * Lock a directory entry. A dirlock on <dzp, name> protects that name + * in dzp's directory zap object. As long as you hold a dirlock, you can + * assume two things: (1) dzp cannot be reaped, and (2) no other thread + * can change the zap entry for (i.e. link or unlink) this name. + * + * Input arguments: + * dzp - znode for directory + * name - name of entry to lock + * flag - ZNEW: if the entry already exists, fail with EEXIST. + * ZEXISTS: if the entry does not exist, fail with ENOENT. + * ZSHARED: allow concurrent access with other ZSHARED callers. + * ZXATTR: we want dzp's xattr directory + * + * Output arguments: + * zpp - pointer to the znode for the entry (NULL if there isn't one) + * dlpp - pointer to the dirlock for this entry (NULL on error) + * + * Return value: 0 on success or errno on failure. + * + * NOTE: Always checks for, and rejects, '.' and '..'. + */ +int +zfs_dirent_lock(zfs_dirlock_t **dlpp, znode_t *dzp, char *name, znode_t **zpp, + int flag) +{ + zfsvfs_t *zfsvfs = dzp->z_zfsvfs; + zfs_dirlock_t *dl; + uint64_t zoid; + int error; + vnode_t *vp; + + *zpp = NULL; + *dlpp = NULL; + + /* + * Verify that we are not trying to lock '.', '..', or '.zfs' + */ + if (name[0] == '.' && + (name[1] == '\0' || (name[1] == '.' && name[2] == '\0')) || + zfs_has_ctldir(dzp) && strcmp(name, ZFS_CTLDIR_NAME) == 0) + return (EEXIST); + + /* + * Wait until there are no locks on this name. + */ + rw_enter(&dzp->z_name_lock, RW_READER); + mutex_enter(&dzp->z_lock); + for (;;) { + if (dzp->z_unlinked) { + mutex_exit(&dzp->z_lock); + rw_exit(&dzp->z_name_lock); + return (ENOENT); + } + for (dl = dzp->z_dirlocks; dl != NULL; dl = dl->dl_next) + if (strcmp(name, dl->dl_name) == 0) + break; + if (dl == NULL) { + /* + * Allocate a new dirlock and add it to the list. + */ + dl = kmem_alloc(sizeof (zfs_dirlock_t), KM_SLEEP); + cv_init(&dl->dl_cv, NULL, CV_DEFAULT, NULL); + dl->dl_name = name; + dl->dl_sharecnt = 0; + dl->dl_namesize = 0; + dl->dl_dzp = dzp; + dl->dl_next = dzp->z_dirlocks; + dzp->z_dirlocks = dl; + break; + } + if ((flag & ZSHARED) && dl->dl_sharecnt != 0) + break; + cv_wait(&dl->dl_cv, &dzp->z_lock); + } + + if ((flag & ZSHARED) && ++dl->dl_sharecnt > 1 && dl->dl_namesize == 0) { + /* + * We're the second shared reference to dl. Make a copy of + * dl_name in case the first thread goes away before we do. + * Note that we initialize the new name before storing its + * pointer into dl_name, because the first thread may load + * dl->dl_name at any time. He'll either see the old value, + * which is his, or the new shared copy; either is OK. + */ + dl->dl_namesize = strlen(dl->dl_name) + 1; + name = kmem_alloc(dl->dl_namesize, KM_SLEEP); + bcopy(dl->dl_name, name, dl->dl_namesize); + dl->dl_name = name; + } + + mutex_exit(&dzp->z_lock); + + /* + * We have a dirlock on the name. (Note that it is the dirlock, + * not the dzp's z_lock, that protects the name in the zap object.) + * See if there's an object by this name; if so, put a hold on it. + */ + if (flag & ZXATTR) { + zoid = dzp->z_phys->zp_xattr; + error = (zoid == 0 ? ENOENT : 0); + } else { + vp = dnlc_lookup(ZTOV(dzp), name); + if (vp == DNLC_NO_VNODE) { + VN_RELE(vp); + error = ENOENT; + } else if (vp) { + if (flag & ZNEW) { + zfs_dirent_unlock(dl); + VN_RELE(vp); + return (EEXIST); + } + *dlpp = dl; + *zpp = VTOZ(vp); + return (0); + } else { + error = zap_lookup(zfsvfs->z_os, dzp->z_id, name, + 8, 1, &zoid); + zoid = ZFS_DIRENT_OBJ(zoid); + if (error == ENOENT) + dnlc_update(ZTOV(dzp), name, DNLC_NO_VNODE); + } + } + if (error) { + if (error != ENOENT || (flag & ZEXISTS)) { + zfs_dirent_unlock(dl); + return (error); + } + } else { + if (flag & ZNEW) { + zfs_dirent_unlock(dl); + return (EEXIST); + } + error = zfs_zget(zfsvfs, zoid, zpp); + if (error) { + zfs_dirent_unlock(dl); + return (error); + } + if (!(flag & ZXATTR)) + dnlc_update(ZTOV(dzp), name, ZTOV(*zpp)); + } + + *dlpp = dl; + + return (0); +} + +/* + * Unlock this directory entry and wake anyone who was waiting for it. + */ +void +zfs_dirent_unlock(zfs_dirlock_t *dl) +{ + znode_t *dzp = dl->dl_dzp; + zfs_dirlock_t **prev_dl, *cur_dl; + + mutex_enter(&dzp->z_lock); + rw_exit(&dzp->z_name_lock); + if (dl->dl_sharecnt > 1) { + dl->dl_sharecnt--; + mutex_exit(&dzp->z_lock); + return; + } + prev_dl = &dzp->z_dirlocks; + while ((cur_dl = *prev_dl) != dl) + prev_dl = &cur_dl->dl_next; + *prev_dl = dl->dl_next; + cv_broadcast(&dl->dl_cv); + mutex_exit(&dzp->z_lock); + + if (dl->dl_namesize != 0) + kmem_free(dl->dl_name, dl->dl_namesize); + cv_destroy(&dl->dl_cv); + kmem_free(dl, sizeof (*dl)); +} + +/* + * Look up an entry in a directory. + * + * NOTE: '.' and '..' are handled as special cases because + * no directory entries are actually stored for them. If this is + * the root of a filesystem, then '.zfs' is also treated as a + * special pseudo-directory. + */ +int +zfs_dirlook(znode_t *dzp, char *name, vnode_t **vpp) +{ + zfs_dirlock_t *dl; + znode_t *zp; + int error = 0; + + if (name[0] == 0 || (name[0] == '.' && name[1] == 0)) { + *vpp = ZTOV(dzp); + VN_HOLD(*vpp); + } else if (name[0] == '.' && name[1] == '.' && name[2] == 0) { + zfsvfs_t *zfsvfs = dzp->z_zfsvfs; + /* + * If we are a snapshot mounted under .zfs, return + * the vp for the snapshot directory. + */ + if (dzp->z_phys->zp_parent == dzp->z_id && + zfsvfs->z_parent != zfsvfs) { + error = zfsctl_root_lookup(zfsvfs->z_parent->z_ctldir, + "snapshot", vpp, NULL, 0, NULL, kcred); + return (error); + } + rw_enter(&dzp->z_parent_lock, RW_READER); + error = zfs_zget(zfsvfs, dzp->z_phys->zp_parent, &zp); + if (error == 0) + *vpp = ZTOV(zp); + rw_exit(&dzp->z_parent_lock); + } else if (zfs_has_ctldir(dzp) && strcmp(name, ZFS_CTLDIR_NAME) == 0) { + *vpp = zfsctl_root(dzp); + } else { + error = zfs_dirent_lock(&dl, dzp, name, &zp, ZEXISTS | ZSHARED); + if (error == 0) { + *vpp = ZTOV(zp); + zfs_dirent_unlock(dl); + dzp->z_zn_prefetch = B_TRUE; /* enable prefetching */ + } + } + + return (error); +} + +static char * +zfs_unlinked_hexname(char namebuf[17], uint64_t x) +{ + char *name = &namebuf[16]; + const char digits[16] = "0123456789abcdef"; + + *name = '\0'; + do { + *--name = digits[x & 0xf]; + x >>= 4; + } while (x != 0); + + return (name); +} + +/* + * unlinked Set (formerly known as the "delete queue") Error Handling + * + * When dealing with the unlinked set, we dmu_tx_hold_zap(), but we + * don't specify the name of the entry that we will be manipulating. We + * also fib and say that we won't be adding any new entries to the + * unlinked set, even though we might (this is to lower the minimum file + * size that can be deleted in a full filesystem). So on the small + * chance that the nlink list is using a fat zap (ie. has more than + * 2000 entries), we *may* not pre-read a block that's needed. + * Therefore it is remotely possible for some of the assertions + * regarding the unlinked set below to fail due to i/o error. On a + * nondebug system, this will result in the space being leaked. + */ +void +zfs_unlinked_add(znode_t *zp, dmu_tx_t *tx) +{ + zfsvfs_t *zfsvfs = zp->z_zfsvfs; + char obj_name[17]; + int error; + + ASSERT(zp->z_unlinked); + ASSERT3U(zp->z_phys->zp_links, ==, 0); + + error = zap_add(zfsvfs->z_os, zfsvfs->z_unlinkedobj, + zfs_unlinked_hexname(obj_name, zp->z_id), 8, 1, &zp->z_id, tx); + ASSERT3U(error, ==, 0); +} + +/* + * Clean up any znodes that had no links when we either crashed or + * (force) umounted the file system. + */ +void +zfs_unlinked_drain(zfsvfs_t *zfsvfs) +{ + zap_cursor_t zc; + zap_attribute_t zap; + dmu_object_info_t doi; + znode_t *zp; + int error; + + /* + * Interate over the contents of the unlinked set. + */ + for (zap_cursor_init(&zc, zfsvfs->z_os, zfsvfs->z_unlinkedobj); + zap_cursor_retrieve(&zc, &zap) == 0; + zap_cursor_advance(&zc)) { + + /* + * See what kind of object we have in list + */ + + error = dmu_object_info(zfsvfs->z_os, + zap.za_first_integer, &doi); + if (error != 0) + continue; + + ASSERT((doi.doi_type == DMU_OT_PLAIN_FILE_CONTENTS) || + (doi.doi_type == DMU_OT_DIRECTORY_CONTENTS)); + /* + * We need to re-mark these list entries for deletion, + * so we pull them back into core and set zp->z_unlinked. + */ + error = zfs_zget(zfsvfs, zap.za_first_integer, &zp); + + /* + * We may pick up znodes that are already marked for deletion. + * This could happen during the purge of an extended attribute + * directory. All we need to do is skip over them, since they + * are already in the system marked z_unlinked. + */ + if (error != 0) + continue; + + zp->z_unlinked = B_TRUE; + VN_RELE(ZTOV(zp)); + } + zap_cursor_fini(&zc); +} + +/* + * Delete the entire contents of a directory. Return a count + * of the number of entries that could not be deleted. + * + * NOTE: this function assumes that the directory is inactive, + * so there is no need to lock its entries before deletion. + * Also, it assumes the directory contents is *only* regular + * files. + */ +static int +zfs_purgedir(znode_t *dzp) +{ + zap_cursor_t zc; + zap_attribute_t zap; + znode_t *xzp; + dmu_tx_t *tx; + zfsvfs_t *zfsvfs = dzp->z_zfsvfs; + zfs_dirlock_t dl; + int skipped = 0; + int error; + + for (zap_cursor_init(&zc, zfsvfs->z_os, dzp->z_id); + (error = zap_cursor_retrieve(&zc, &zap)) == 0; + zap_cursor_advance(&zc)) { + error = zfs_zget(zfsvfs, + ZFS_DIRENT_OBJ(zap.za_first_integer), &xzp); + ASSERT3U(error, ==, 0); + + ASSERT((ZTOV(xzp)->v_type == VREG) || + (ZTOV(xzp)->v_type == VLNK)); + + tx = dmu_tx_create(zfsvfs->z_os); + dmu_tx_hold_bonus(tx, dzp->z_id); + dmu_tx_hold_zap(tx, dzp->z_id, FALSE, zap.za_name); + dmu_tx_hold_bonus(tx, xzp->z_id); + dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL); + error = dmu_tx_assign(tx, TXG_WAIT); + if (error) { + dmu_tx_abort(tx); + VN_RELE(ZTOV(xzp)); + skipped += 1; + continue; + } + bzero(&dl, sizeof (dl)); + dl.dl_dzp = dzp; + dl.dl_name = zap.za_name; + + error = zfs_link_destroy(&dl, xzp, tx, 0, NULL); + ASSERT3U(error, ==, 0); + dmu_tx_commit(tx); + + VN_RELE(ZTOV(xzp)); + } + zap_cursor_fini(&zc); + ASSERT(error == ENOENT); + return (skipped); +} + +void +zfs_rmnode(znode_t *zp) +{ + zfsvfs_t *zfsvfs = zp->z_zfsvfs; + objset_t *os = zfsvfs->z_os; + znode_t *xzp = NULL; + char obj_name[17]; + dmu_tx_t *tx; + uint64_t acl_obj; + int error; + int vfslocked; + + vfslocked = VFS_LOCK_GIANT(zfsvfs->z_vfs); + + ASSERT(zp->z_phys->zp_links == 0); + + /* + * If this is an attribute directory, purge its contents. + */ + if (ZTOV(zp) != NULL && ZTOV(zp)->v_type == VDIR && + (zp->z_phys->zp_flags & ZFS_XATTR)) { + if (zfs_purgedir(zp) != 0) { + /* + * Not enough space to delete some xattrs. + * Leave it on the unlinked set. + */ + VFS_UNLOCK_GIANT(vfslocked); + return; + } + } + + /* + * If the file has extended attributes, we're going to unlink + * the xattr dir. + */ + if (zp->z_phys->zp_xattr) { + error = zfs_zget(zfsvfs, zp->z_phys->zp_xattr, &xzp); + ASSERT(error == 0); + } + + acl_obj = zp->z_phys->zp_acl.z_acl_extern_obj; + + /* + * Set up the transaction. + */ + tx = dmu_tx_create(os); + dmu_tx_hold_free(tx, zp->z_id, 0, DMU_OBJECT_END); + dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL); + if (xzp) { + dmu_tx_hold_bonus(tx, xzp->z_id); + dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, TRUE, NULL); + } + if (acl_obj) + dmu_tx_hold_free(tx, acl_obj, 0, DMU_OBJECT_END); + error = dmu_tx_assign(tx, TXG_WAIT); + if (error) { + /* + * Not enough space to delete the file. Leave it in the + * unlinked set, leaking it until the fs is remounted (at + * which point we'll call zfs_unlinked_drain() to process it). + */ + dmu_tx_abort(tx); + VFS_UNLOCK_GIANT(vfslocked); + return; + } + + if (xzp) { + dmu_buf_will_dirty(xzp->z_dbuf, tx); + mutex_enter(&xzp->z_lock); + xzp->z_unlinked = B_TRUE; /* mark xzp for deletion */ + xzp->z_phys->zp_links = 0; /* no more links to it */ + mutex_exit(&xzp->z_lock); + zfs_unlinked_add(xzp, tx); + } + + /* Remove this znode from the unlinked set */ + error = zap_remove(os, zfsvfs->z_unlinkedobj, + zfs_unlinked_hexname(obj_name, zp->z_id), tx); + ASSERT3U(error, ==, 0); + + zfs_znode_delete(zp, tx); + + dmu_tx_commit(tx); + + if (xzp) + VN_RELE(ZTOV(xzp)); + VFS_UNLOCK_GIANT(vfslocked); +} + +/* + * Link zp into dl. Can only fail if zp has been unlinked. + */ +int +zfs_link_create(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag) +{ + znode_t *dzp = dl->dl_dzp; + vnode_t *vp = ZTOV(zp); + uint64_t value; + int zp_is_dir = (vp->v_type == VDIR); + int error; + + dmu_buf_will_dirty(zp->z_dbuf, tx); + mutex_enter(&zp->z_lock); + + if (!(flag & ZRENAMING)) { + if (zp->z_unlinked) { /* no new links to unlinked zp */ + ASSERT(!(flag & (ZNEW | ZEXISTS))); + mutex_exit(&zp->z_lock); + return (ENOENT); + } + zp->z_phys->zp_links++; + } + zp->z_phys->zp_parent = dzp->z_id; /* dzp is now zp's parent */ + + if (!(flag & ZNEW)) + zfs_time_stamper_locked(zp, STATE_CHANGED, tx); + mutex_exit(&zp->z_lock); + + dmu_buf_will_dirty(dzp->z_dbuf, tx); + mutex_enter(&dzp->z_lock); + dzp->z_phys->zp_size++; /* one dirent added */ + dzp->z_phys->zp_links += zp_is_dir; /* ".." link from zp */ + zfs_time_stamper_locked(dzp, CONTENT_MODIFIED, tx); + mutex_exit(&dzp->z_lock); + + /* + * MacOS X will fill in the 4-bit object type here. + */ + value = ZFS_DIRENT_MAKE(IFTODT(zp->z_phys->zp_mode), zp->z_id); + error = zap_add(zp->z_zfsvfs->z_os, dzp->z_id, dl->dl_name, + 8, 1, &value, tx); + ASSERT(error == 0); + + dnlc_update(ZTOV(dzp), dl->dl_name, vp); + + return (0); +} + +/* + * Unlink zp from dl, and mark zp for deletion if this was the last link. + * Can fail if zp is a mount point (EBUSY) or a non-empty directory (EEXIST). + * If 'unlinkedp' is NULL, we put unlinked znodes on the unlinked list. + * If it's non-NULL, we use it to indicate whether the znode needs deletion, + * and it's the caller's job to do it. + */ +int +zfs_link_destroy(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag, + boolean_t *unlinkedp) +{ + znode_t *dzp = dl->dl_dzp; + vnode_t *vp = ZTOV(zp); + int zp_is_dir = (vp->v_type == VDIR); + boolean_t unlinked = B_FALSE; + int error; + + dnlc_remove(ZTOV(dzp), dl->dl_name); + + if (!(flag & ZRENAMING)) { + dmu_buf_will_dirty(zp->z_dbuf, tx); + + if (vn_vfswlock(vp)) /* prevent new mounts on zp */ + return (EBUSY); + + if (vn_ismntpt(vp)) { /* don't remove mount point */ + vn_vfsunlock(vp); + return (EBUSY); + } + + mutex_enter(&zp->z_lock); + if (zp_is_dir && !zfs_dirempty(zp)) { /* dir not empty */ + mutex_exit(&zp->z_lock); + vn_vfsunlock(vp); + return (ENOTEMPTY); + } + if (zp->z_phys->zp_links <= zp_is_dir) { + zfs_panic_recover("zfs: link count on vnode %p is %u, " + "should be at least %u", zp->z_vnode, + (int)zp->z_phys->zp_links, + zp_is_dir + 1); + zp->z_phys->zp_links = zp_is_dir + 1; + } + if (--zp->z_phys->zp_links == zp_is_dir) { + zp->z_unlinked = B_TRUE; + zp->z_phys->zp_links = 0; + unlinked = B_TRUE; + } else { + zfs_time_stamper_locked(zp, STATE_CHANGED, tx); + } + mutex_exit(&zp->z_lock); + vn_vfsunlock(vp); + } + + dmu_buf_will_dirty(dzp->z_dbuf, tx); + mutex_enter(&dzp->z_lock); + dzp->z_phys->zp_size--; /* one dirent removed */ + dzp->z_phys->zp_links -= zp_is_dir; /* ".." link from zp */ + zfs_time_stamper_locked(dzp, CONTENT_MODIFIED, tx); + mutex_exit(&dzp->z_lock); + + error = zap_remove(zp->z_zfsvfs->z_os, dzp->z_id, dl->dl_name, tx); + ASSERT(error == 0); + + if (unlinkedp != NULL) + *unlinkedp = unlinked; + else if (unlinked) + zfs_unlinked_add(zp, tx); + + return (0); +} + +/* + * Indicate whether the directory is empty. Works with or without z_lock + * held, but can only be consider a hint in the latter case. Returns true + * if only "." and ".." remain and there's no work in progress. + */ +boolean_t +zfs_dirempty(znode_t *dzp) +{ + return (dzp->z_phys->zp_size == 2 && dzp->z_dirlocks == 0); +} + +int +zfs_make_xattrdir(znode_t *zp, vattr_t *vap, vnode_t **xvpp, cred_t *cr) +{ + zfsvfs_t *zfsvfs = zp->z_zfsvfs; + znode_t *xzp; + dmu_tx_t *tx; + uint64_t xoid; + int error; + + *xvpp = NULL; + + if (error = zfs_zaccess(zp, ACE_WRITE_NAMED_ATTRS, cr)) + return (error); + + tx = dmu_tx_create(zfsvfs->z_os); + dmu_tx_hold_bonus(tx, zp->z_id); + dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL); + error = dmu_tx_assign(tx, zfsvfs->z_assign); + if (error) { + if (error == ERESTART && zfsvfs->z_assign == TXG_NOWAIT) + dmu_tx_wait(tx); + dmu_tx_abort(tx); + return (error); + } + zfs_mknode(zp, vap, &xoid, tx, cr, IS_XATTR, &xzp, 0); + ASSERT(xzp->z_id == xoid); + ASSERT(xzp->z_phys->zp_parent == zp->z_id); + dmu_buf_will_dirty(zp->z_dbuf, tx); + zp->z_phys->zp_xattr = xoid; + + (void) zfs_log_create(zfsvfs->z_log, tx, TX_MKXATTR, zp, xzp, ""); + dmu_tx_commit(tx); + + *xvpp = ZTOV(xzp); + + return (0); +} + +/* + * Return a znode for the extended attribute directory for zp. + * ** If the directory does not already exist, it is created ** + * + * IN: zp - znode to obtain attribute directory from + * cr - credentials of caller + * flags - flags from the VOP_LOOKUP call + * + * OUT: xzpp - pointer to extended attribute znode + * + * RETURN: 0 on success + * error number on failure + */ +int +zfs_get_xattrdir(znode_t *zp, vnode_t **xvpp, cred_t *cr, int flags) +{ + zfsvfs_t *zfsvfs = zp->z_zfsvfs; + znode_t *xzp; + zfs_dirlock_t *dl; + vattr_t va; + int error; +top: + error = zfs_dirent_lock(&dl, zp, "", &xzp, ZXATTR); + if (error) + return (error); + + if (xzp != NULL) { + *xvpp = ZTOV(xzp); + zfs_dirent_unlock(dl); + return (0); + } + + ASSERT(zp->z_phys->zp_xattr == 0); + +#ifdef TODO + if (!(flags & CREATE_XATTR_DIR)) { + zfs_dirent_unlock(dl); + return (ENOENT); + } +#endif + + if (zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) { + zfs_dirent_unlock(dl); + return (EROFS); + } + + /* + * The ability to 'create' files in an attribute + * directory comes from the write_xattr permission on the base file. + * + * The ability to 'search' an attribute directory requires + * read_xattr permission on the base file. + * + * Once in a directory the ability to read/write attributes + * is controlled by the permissions on the attribute file. + */ + va.va_mask = AT_TYPE | AT_MODE | AT_UID | AT_GID; + va.va_type = VDIR; + va.va_mode = S_IFDIR | S_ISVTX | 0777; + va.va_uid = (uid_t)zp->z_phys->zp_uid; + va.va_gid = (gid_t)zp->z_phys->zp_gid; + + error = zfs_make_xattrdir(zp, &va, xvpp, cr); + zfs_dirent_unlock(dl); + + if (error == ERESTART && zfsvfs->z_assign == TXG_NOWAIT) { + /* NB: we already did dmu_tx_wait() if necessary */ + goto top; + } + + return (error); +} + +/* + * Decide whether it is okay to remove within a sticky directory. + * + * In sticky directories, write access is not sufficient; + * you can remove entries from a directory only if: + * + * you own the directory, + * you own the entry, + * the entry is a plain file and you have write access, + * or you are privileged (checked in secpolicy...). + * + * The function returns 0 if remove access is granted. + */ +int +zfs_sticky_remove_access(znode_t *zdp, znode_t *zp, cred_t *cr) +{ + uid_t uid; + + if (zdp->z_zfsvfs->z_assign >= TXG_INITIAL) /* ZIL replay */ + return (0); + + if ((zdp->z_phys->zp_mode & S_ISVTX) == 0 || + (uid = crgetuid(cr)) == zdp->z_phys->zp_uid || + uid == zp->z_phys->zp_uid || + (ZTOV(zp)->v_type == VREG && + zfs_zaccess(zp, ACE_WRITE_DATA, cr) == 0)) + return (0); + else + return (secpolicy_vnode_remove(cr)); +} |