Author: kevans Date: Mon Apr 22 13:43:38 2019 New Revision: 346545 URL: https://svnweb.freebsd.org/changeset/base/346545
Log: libbe(3): allow creation of arbitrary depth boot environments libbe currently only provides an API to create a recursive boot environment, without any formal support for intentionally limiting the depth. This changeset adds an API, be_create_depth, that may be used to arbitrarily restrict the depth of the new BE. Submitted by: Rob Fairbanks <rob.fx907 gmail com> MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D18564 Modified: head/lib/libbe/be.c head/lib/libbe/be.h head/lib/libbe/be_impl.h head/lib/libbe/libbe.3 Modified: head/lib/libbe/be.c ============================================================================== --- head/lib/libbe/be.c Mon Apr 22 11:31:13 2019 (r346544) +++ head/lib/libbe/be.c Mon Apr 22 13:43:38 2019 (r346545) @@ -372,7 +372,6 @@ be_snapshot(libbe_handle_t *lbh, const char *source, c sizeof(buf)) >= sizeof(buf)) return (set_error(lbh, BE_ERR_INVALIDNAME)); } - if ((err = zfs_snapshot(lbh->lzh, buf, recursive, NULL)) != 0) { switch (err) { case EZFS_INVALIDNAME: @@ -446,43 +445,78 @@ be_deep_clone_prop(int prop, void *cb) return (ZPROP_CONT); } +/* + * Return the corresponding boot environment path for a given + * dataset path, the constructed path is placed in 'result'. + * + * example: say our new boot environment name is 'bootenv' and + * the dataset path is 'zroot/ROOT/default/data/set'. + * + * result should produce: 'zroot/ROOT/bootenv/data/set' + */ static int -be_deep_clone(zfs_handle_t *ds, void *data) +be_get_path(struct libbe_deep_clone *ldc, const char *dspath, char *result, int result_size) { + char *pos; + char *child_dataset; + + /* match the root path for the boot environments */ + pos = strstr(dspath, ldc->lbh->root); + + /* no match, different pools? */ + if (pos == NULL) + return (BE_ERR_BADPATH); + + /* root path of the new boot environment */ + snprintf(result, result_size, "%s/%s", ldc->lbh->root, ldc->bename); + + /* gets us to the parent dataset, the +1 consumes a trailing slash */ + pos += strlen(ldc->lbh->root) + 1; + + /* skip the parent dataset */ + if ((child_dataset = strchr(pos, '/')) != NULL) + strlcat(result, child_dataset, result_size); + + return (BE_ERR_SUCCESS); +} + +static int +be_clone_cb(zfs_handle_t *ds, void *data) +{ int err; char be_path[BE_MAXPATHLEN]; char snap_path[BE_MAXPATHLEN]; const char *dspath; - char *dsname; zfs_handle_t *snap_hdl; nvlist_t *props; - struct libbe_deep_clone *isdc, sdc; + struct libbe_deep_clone *ldc; struct libbe_dccb dccb; - isdc = (struct libbe_deep_clone *)data; + ldc = (struct libbe_deep_clone *)data; dspath = zfs_get_name(ds); - if ((dsname = strrchr(dspath, '/')) == NULL) - return (BE_ERR_UNKNOWN); - dsname++; - if (isdc->bename == NULL) - snprintf(be_path, sizeof(be_path), "%s/%s", isdc->be_root, dsname); - else - snprintf(be_path, sizeof(be_path), "%s/%s", isdc->be_root, isdc->bename); + snprintf(snap_path, sizeof(snap_path), "%s@%s", dspath, ldc->snapname); - snprintf(snap_path, sizeof(snap_path), "%s@%s", dspath, isdc->snapname); + /* construct the boot environment path from the dataset we're cloning */ + if (be_get_path(ldc, dspath, be_path, sizeof(be_path)) != BE_ERR_SUCCESS) + return (set_error(ldc->lbh, BE_ERR_UNKNOWN)); - if (zfs_dataset_exists(isdc->lbh->lzh, be_path, ZFS_TYPE_DATASET)) - return (set_error(isdc->lbh, BE_ERR_EXISTS)); + /* the dataset to be created (i.e. the boot environment) already exists */ + if (zfs_dataset_exists(ldc->lbh->lzh, be_path, ZFS_TYPE_DATASET)) + return (set_error(ldc->lbh, BE_ERR_EXISTS)); + /* no snapshot found for this dataset, silently skip it */ + if (!zfs_dataset_exists(ldc->lbh->lzh, snap_path, ZFS_TYPE_SNAPSHOT)) + return (0); + if ((snap_hdl = - zfs_open(isdc->lbh->lzh, snap_path, ZFS_TYPE_SNAPSHOT)) == NULL) - return (set_error(isdc->lbh, BE_ERR_ZFSOPEN)); + zfs_open(ldc->lbh->lzh, snap_path, ZFS_TYPE_SNAPSHOT)) == NULL) + return (set_error(ldc->lbh, BE_ERR_ZFSOPEN)); nvlist_alloc(&props, NV_UNIQUE_NAME, KM_SLEEP); nvlist_add_string(props, "canmount", "noauto"); - dccb.lbh = isdc->lbh; + dccb.lbh = ldc->lbh; dccb.zhp = ds; dccb.props = props; if (zprop_iter(be_deep_clone_prop, &dccb, B_FALSE, B_FALSE, @@ -490,58 +524,55 @@ be_deep_clone(zfs_handle_t *ds, void *data) return (-1); if ((err = zfs_clone(snap_hdl, be_path, props)) != 0) - err = BE_ERR_ZFSCLONE; + return (set_error(ldc->lbh, BE_ERR_ZFSCLONE)); nvlist_free(props); zfs_close(snap_hdl); - /* Failed to clone */ - if (err != BE_ERR_SUCCESS) - return (set_error(isdc->lbh, err)); + if (ldc->depth_limit == -1 || ldc->depth < ldc->depth_limit) { + ldc->depth++; + err = zfs_iter_filesystems(ds, be_clone_cb, ldc); + ldc->depth--; + } - sdc.lbh = isdc->lbh; - sdc.bename = NULL; - sdc.snapname = isdc->snapname; - sdc.be_root = (char *)&be_path; - - err = zfs_iter_filesystems(ds, be_deep_clone, &sdc); - - return (err); + return (set_error(ldc->lbh, err)); } /* - * Create the boot environment from pre-existing snapshot - */ -int -be_create_from_existing_snap(libbe_handle_t *lbh, const char *name, - const char *snap) + * Create a boot environment with a given name from a given snapshot. + * Snapshots can be in the format 'zroot/ROOT/default@snapshot' or + * 'default@snapshot'. In the latter case, 'default@snapshot' will be prepended + * with the root path that libbe was initailized with. +*/ +static int +be_clone(libbe_handle_t *lbh, const char *bename, const char *snapshot, int depth) { int err; - char be_path[BE_MAXPATHLEN]; char snap_path[BE_MAXPATHLEN]; - const char *bename; char *parentname, *snapname; zfs_handle_t *parent_hdl; - struct libbe_deep_clone sdc; + struct libbe_deep_clone ldc; - if ((err = be_validate_name(lbh, name)) != 0) + /* ensure the boot environment name is valid */ + if ((err = be_validate_name(lbh, bename)) != 0) return (set_error(lbh, err)); - if ((err = be_root_concat(lbh, snap, snap_path)) != 0) + + /* + * prepend the boot environment root path if we're + * given a partial snapshot name. + */ + if ((err = be_root_concat(lbh, snapshot, snap_path)) != 0) return (set_error(lbh, err)); + + /* ensure the snapshot exists */ if ((err = be_validate_snap(lbh, snap_path)) != 0) return (set_error(lbh, err)); - if ((err = be_root_concat(lbh, name, be_path)) != 0) - return (set_error(lbh, err)); - - if ((bename = strrchr(name, '/')) == NULL) - bename = name; - else - bename++; - + /* get a copy of the snapshot path so we can disect it */ if ((parentname = strdup(snap_path)) == NULL) return (set_error(lbh, BE_ERR_UNKNOWN)); + /* split dataset name from snapshot name */ snapname = strchr(parentname, '@'); if (snapname == NULL) { free(parentname); @@ -550,32 +581,56 @@ be_create_from_existing_snap(libbe_handle_t *lbh, cons *snapname = '\0'; snapname++; - sdc.lbh = lbh; - sdc.bename = bename; - sdc.snapname = snapname; - sdc.be_root = lbh->root; + /* set-up the boot environment */ + ldc.lbh = lbh; + ldc.bename = bename; + ldc.snapname = snapname; + ldc.depth = 0; + ldc.depth_limit = depth; + /* the boot environment will be cloned from this dataset */ parent_hdl = zfs_open(lbh->lzh, parentname, ZFS_TYPE_DATASET); - err = be_deep_clone(parent_hdl, &sdc); + /* create the boot environment */ + err = be_clone_cb(parent_hdl, &ldc); + free(parentname); return (set_error(lbh, err)); } +/* + * Create a boot environment from pre-existing snapshot, specifying a depth. + */ +int be_create_depth(libbe_handle_t *lbh, const char *bename, + const char *snap, int depth) +{ + return (be_clone(lbh, bename, snap, depth)); +} /* + * Create the boot environment from pre-existing snapshot + */ +int +be_create_from_existing_snap(libbe_handle_t *lbh, const char *bename, + const char *snap) +{ + return (be_clone(lbh, bename, snap, -1)); +} + + +/* * Create a boot environment from an existing boot environment */ int -be_create_from_existing(libbe_handle_t *lbh, const char *name, const char *old) +be_create_from_existing(libbe_handle_t *lbh, const char *bename, const char *old) { int err; - char buf[BE_MAXPATHLEN]; + char snap[BE_MAXPATHLEN]; - if ((err = be_snapshot(lbh, old, NULL, true, (char *)&buf)) != 0) + if ((err = be_snapshot(lbh, old, NULL, true, snap)) != 0) return (set_error(lbh, err)); - err = be_create_from_existing_snap(lbh, name, (char *)buf); + err = be_clone(lbh, bename, snap, -1); return (set_error(lbh, err)); } Modified: head/lib/libbe/be.h ============================================================================== --- head/lib/libbe/be.h Mon Apr 22 11:31:13 2019 (r346544) +++ head/lib/libbe/be.h Mon Apr 22 13:43:38 2019 (r346545) @@ -84,6 +84,7 @@ int be_activate(libbe_handle_t *, const char *, bool); /* Bootenv creation functions */ int be_create(libbe_handle_t *, const char *); +int be_create_depth(libbe_handle_t *, const char *, const char *, int); int be_create_from_existing(libbe_handle_t *, const char *, const char *); int be_create_from_existing_snap(libbe_handle_t *, const char *, const char *); int be_snapshot(libbe_handle_t *, const char *, const char *, bool, char *); Modified: head/lib/libbe/be_impl.h ============================================================================== --- head/lib/libbe/be_impl.h Mon Apr 22 11:31:13 2019 (r346544) +++ head/lib/libbe/be_impl.h Mon Apr 22 13:43:38 2019 (r346545) @@ -50,7 +50,8 @@ struct libbe_deep_clone { libbe_handle_t *lbh; const char *bename; const char *snapname; - const char *be_root; + int depth; + int depth_limit; }; struct libbe_dccb { Modified: head/lib/libbe/libbe.3 ============================================================================== --- head/lib/libbe/libbe.3 Mon Apr 22 11:31:13 2019 (r346544) +++ head/lib/libbe/libbe.3 Mon Apr 22 13:43:38 2019 (r346545) @@ -28,7 +28,7 @@ .\" .\" $FreeBSD$ .\" -.Dd February 12, 2019 +.Dd April 22, 2019 .Dt LIBBE 3 .Os .Sh NAME @@ -63,6 +63,9 @@ .Fn be_create "libbe_handle_t *hdl" "const char *be_name" .Pp .Ft int +.Fn be_create_depth "libbe_handle_t *hdl" "const char *be_name" "const char *snap" "int depth" +.Pp +.Ft int .Fn be_create_from_existing "libbe_handle_t *hdl" "const char *be_name" "const char *be_origin" .Pp .Ft int @@ -213,19 +216,29 @@ function returns the boot environment root path. The .Fn be_create function creates a boot environment with the given name. -It will be created from a snapshot of the currently booted boot environment. +The new boot environment will be created from a recursive snapshot of the +currently booted boot environment. .Pp The +.Fn be_create_depth +function creates a boot environment with the given name from an existing +snapshot. +The depth parameter specifies the depth of recursion that will be cloned from +the existing snapshot. +A depth of '0' is no recursion and '-1' is unlimited (i.e., a recursive boot +environment). +.Pp +The .Fn be_create_from_existing function creates a boot environment with the given name from the name of an existing boot environment. -A snapshot will be made of the base boot environment, and the new boot -environment will be created from that. +A recursive snapshot will be made of the origin boot environment, and the new +boot environment will be created from that. .Pp The .Fn be_create_from_existing_snap -function creates a boot environment with the given name from an existing -snapshot. +function creates a recursive boot environment with the given name from an +existing snapshot. .Pp The .Fn be_rename _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
