btrfs-progs: image: move metadump definitions to own header
[platform/upstream/btrfs-progs.git] / cmds-subvolume.c
index d2e37bb..dc626a6 100644 (file)
 #include <sys/ioctl.h>
 #include <errno.h>
 #include <sys/stat.h>
+#include <sys/vfs.h>
 #include <libgen.h>
 #include <limits.h>
 #include <getopt.h>
 #include <uuid/uuid.h>
+#include <linux/magic.h>
 
 #include "kerncompat.h"
 #include "ioctl.h"
@@ -35,6 +37,7 @@
 #include "utils.h"
 #include "btrfs-list.h"
 #include "utils.h"
+#include "help.h"
 
 static int is_subvolume_cleaned(int fd, u64 subvolid)
 {
@@ -67,35 +70,34 @@ static int wait_for_subvolume_cleaning(int fd, int count, u64 *ids,
                int sleep_interval)
 {
        int ret;
-       int remaining;
        int i;
 
-       remaining = count;
        while (1) {
+               int clean = 1;
+
                for (i = 0; i < count; i++) {
                        if (!ids[i])
                                continue;
                        ret = is_subvolume_cleaned(fd, ids[i]);
                        if (ret < 0) {
-                               fprintf(stderr,
-                                       "ERROR: can't perform the search - %s\n",
-                                       strerror(-ret));
-                               goto out;
+                               error(
+                           "cannot read status of dead subvolume %llu: %s",
+                                       (unsigned long long)ids[i], strerror(-ret));
+                               return ret;
                        }
                        if (ret) {
                                printf("Subvolume id %llu is gone\n", ids[i]);
                                ids[i] = 0;
-                               remaining--;
+                       } else {
+                               clean = 0;
                        }
                }
-               if (!remaining)
+               if (clean)
                        break;
                sleep(sleep_interval);
        }
 
-       ret = 0;
-out:
-       return ret;
+       return 0;
 }
 
 static const char * const subvolume_cmd_group_usage[] = {
@@ -126,9 +128,8 @@ static int cmd_subvol_create(int argc, char **argv)
        struct btrfs_qgroup_inherit *inherit = NULL;
        DIR     *dirstream = NULL;
 
-       optind = 1;
        while (1) {
-               int c = getopt(argc, argv, "c:i:v");
+               int c = getopt(argc, argv, "c:i:");
                if (c < 0)
                        break;
 
@@ -159,8 +160,12 @@ static int cmd_subvol_create(int argc, char **argv)
 
        retval = 1;     /* failure */
        res = test_isdir(dst);
+       if (res < 0 && res != -ENOENT) {
+               error("cannot access %s: %s", dst, strerror(-res));
+               goto out;
+       }
        if (res >= 0) {
-               fprintf(stderr, "ERROR: '%s' exists\n", dst);
+               error("target path already exists: %s", dst);
                goto out;
        }
 
@@ -170,23 +175,19 @@ static int cmd_subvol_create(int argc, char **argv)
        dstdir = dirname(dupdir);
 
        if (!test_issubvolname(newname)) {
-               fprintf(stderr, "ERROR: incorrect subvolume name '%s'\n",
-                       newname);
+               error("invalid subvolume name: %s", newname);
                goto out;
        }
 
        len = strlen(newname);
        if (len == 0 || len >= BTRFS_VOL_NAME_MAX) {
-               fprintf(stderr, "ERROR: subvolume name too long '%s'\n",
-                       newname);
+               error("subvolume name too long: %s", newname);
                goto out;
        }
 
-       fddst = open_file_or_dir(dstdir, &dirstream);
-       if (fddst < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", dstdir);
+       fddst = btrfs_open_dir(dstdir, &dirstream, 1);
+       if (fddst < 0)
                goto out;
-       }
 
        printf("Create subvolume '%s/%s'\n", dstdir, newname);
        if (inherit) {
@@ -209,8 +210,7 @@ static int cmd_subvol_create(int argc, char **argv)
        }
 
        if (res < 0) {
-               fprintf(stderr, "ERROR: cannot create subvolume - %s\n",
-                       strerror(errno));
+               error("cannot create subvolume: %s", strerror(errno));
                goto out;
        }
 
@@ -224,25 +224,6 @@ out:
        return retval;
 }
 
-/*
- * test if path is a subvolume:
- * this function return
- * 0-> path exists but it is not a subvolume
- * 1-> path exists and it is  a subvolume
- * -1 -> path is unaccessible
- */
-int test_issubvolume(char *path)
-{
-       struct stat     st;
-       int             res;
-
-       res = stat(path, &st);
-       if(res < 0 )
-               return -1;
-
-       return (st.st_ino == 256) && S_ISDIR(st.st_mode);
-}
-
 static int wait_for_commit(int fd)
 {
        int ret;
@@ -265,12 +246,13 @@ static const char * const cmd_subvol_delete_usage[] = {
        "",
        "-c|--commit-after      wait for transaction commit at the end of the operation",
        "-C|--commit-each       wait for transaction commit after deleting each subvolume",
+       "-v|--verbose           verbose output of operations",
        NULL
 };
 
 static int cmd_subvol_delete(int argc, char **argv)
 {
-       int     res, e, ret = 0;
+       int res, ret = 0;
        int cnt;
        int fd = -1;
        struct btrfs_ioctl_vol_args     args;
@@ -281,26 +263,30 @@ static int cmd_subvol_delete(int argc, char **argv)
        DIR     *dirstream = NULL;
        int verbose = 0;
        int commit_mode = 0;
+       u8 fsid[BTRFS_FSID_SIZE];
+       char uuidbuf[BTRFS_UUID_UNPARSED_SIZE];
+       struct seen_fsid *seen_fsid_hash[SEEN_FSID_HASH_SIZE] = { NULL, };
+       enum { COMMIT_AFTER = 1, COMMIT_EACH = 2 };
 
-       optind = 1;
        while (1) {
                int c;
                static const struct option long_options[] = {
-                       {"commit-after", no_argument, NULL, 'c'},  /* commit mode 1 */
-                       {"commit-each", no_argument, NULL, 'C'},  /* commit mode 2 */
+                       {"commit-after", no_argument, NULL, 'c'},
+                       {"commit-each", no_argument, NULL, 'C'},
+                       {"verbose", no_argument, NULL, 'v'},
                        {NULL, 0, NULL, 0}
                };
 
-               c = getopt_long(argc, argv, "cC", long_options, NULL);
+               c = getopt_long(argc, argv, "cCv", long_options, NULL);
                if (c < 0)
                        break;
 
                switch(c) {
                case 'c':
-                       commit_mode = 1;
+                       commit_mode = COMMIT_AFTER;
                        break;
                case 'C':
-                       commit_mode = 2;
+                       commit_mode = COMMIT_EACH;
                        break;
                case 'v':
                        verbose++;
@@ -316,7 +302,7 @@ static int cmd_subvol_delete(int argc, char **argv)
        if (verbose > 0) {
                printf("Transaction commit: %s\n",
                        !commit_mode ? "none (default)" :
-                       commit_mode == 1 ? "at the end" : "after each");
+                       commit_mode == COMMIT_AFTER ? "at the end" : "after each");
        }
 
        cnt = optind;
@@ -326,12 +312,12 @@ again:
 
        res = test_issubvolume(path);
        if (res < 0) {
-               fprintf(stderr, "ERROR: error accessing '%s'\n", path);
+               error("cannot access subvolume %s: %s", path, strerror(-res));
                ret = 1;
                goto out;
        }
        if (!res) {
-               fprintf(stderr, "ERROR: '%s' is not a subvolume\n", path);
+               error("not a subvolume: %s", path);
                ret = 1;
                goto out;
        }
@@ -339,7 +325,7 @@ again:
        cpath = realpath(path, NULL);
        if (!cpath) {
                ret = errno;
-               fprintf(stderr, "ERROR: finding real path for '%s': %s\n",
+               error("cannot find real path for '%s': %s",
                        path, strerror(errno));
                goto out;
        }
@@ -349,62 +335,100 @@ again:
        vname = basename(dupvname);
        free(cpath);
 
-       fd = open_file_or_dir(dname, &dirstream);
+       fd = btrfs_open_dir(dname, &dirstream, 1);
        if (fd < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", dname);
                ret = 1;
                goto out;
        }
 
        printf("Delete subvolume (%s): '%s/%s'\n",
-               commit_mode == 2 || (commit_mode == 1 && cnt + 1 == argc)
+               commit_mode == COMMIT_EACH || (commit_mode == COMMIT_AFTER && cnt + 1 == argc)
                ? "commit" : "no-commit", dname, vname);
        memset(&args, 0, sizeof(args));
        strncpy_null(args.name, vname);
        res = ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &args);
-       e = errno;
-
        if(res < 0 ){
-               fprintf( stderr, "ERROR: cannot delete '%s/%s' - %s\n",
-                       dname, vname, strerror(e));
+               error("cannot delete '%s/%s': %s", dname, vname,
+                       strerror(errno));
                ret = 1;
                goto out;
        }
 
-       if (commit_mode == 1) {
+       if (commit_mode == COMMIT_EACH) {
                res = wait_for_commit(fd);
                if (res < 0) {
-                       fprintf(stderr,
-                               "ERROR: unable to wait for commit after '%s': %s\n",
+                       error("unable to wait for commit after '%s': %s",
                                path, strerror(errno));
                        ret = 1;
                }
+       } else if (commit_mode == COMMIT_AFTER) {
+               res = get_fsid(dname, fsid, 0);
+               if (res < 0) {
+                       error("unable to get fsid for '%s': %s",
+                               path, strerror(-res));
+                       error(
+                       "delete suceeded but commit may not be done in the end");
+                       ret = 1;
+                       goto out;
+               }
+
+               if (add_seen_fsid(fsid, seen_fsid_hash, fd, dirstream) == 0) {
+                       if (verbose > 0) {
+                               uuid_unparse(fsid, uuidbuf);
+                               printf("  new fs is found for '%s', fsid: %s\n",
+                                               path, uuidbuf);
+                       }
+                       /*
+                        * This is the first time a subvolume on this
+                        * filesystem is deleted, keep fd in order to issue
+                        * SYNC ioctl in the end
+                        */
+                       goto keep_fd;
+               }
        }
 
 out:
+       close_file_or_dir(fd, dirstream);
+keep_fd:
+       fd = -1;
+       dirstream = NULL;
        free(dupdname);
        free(dupvname);
        dupdname = NULL;
        dupvname = NULL;
        cnt++;
-       if (cnt < argc) {
-               close_file_or_dir(fd, dirstream);
-               /* avoid double free */
-               fd = -1;
-               dirstream = NULL;
+       if (cnt < argc)
                goto again;
-       }
 
-       if (commit_mode == 2 && fd != -1) {
-               res = wait_for_commit(fd);
-               if (res < 0) {
-                       fprintf(stderr,
-                               "ERROR: unable to do final sync: %s\n",
-                               strerror(errno));
-                       ret = 1;
+       if (commit_mode == COMMIT_AFTER) {
+               int slot;
+
+               /*
+                * Traverse seen_fsid_hash and issue SYNC ioctl on each
+                * filesystem
+                */
+               for (slot = 0; slot < SEEN_FSID_HASH_SIZE; slot++) {
+                       struct seen_fsid *seen = seen_fsid_hash[slot];
+
+                       while (seen) {
+                               res = wait_for_commit(seen->fd);
+                               if (res < 0) {
+                                       uuid_unparse(seen->fsid, uuidbuf);
+                                       error(
+                       "unable to do final sync after deletion: %s, fsid: %s",
+                                               strerror(errno), uuidbuf);
+                                       ret = 1;
+                               } else if (verbose > 0) {
+                                       uuid_unparse(seen->fsid, uuidbuf);
+                                       printf("final sync is done for fsid: %s\n",
+                                               uuidbuf);
+                               }
+                               seen = seen->next;
+                       }
                }
+               /* fd will also be closed in free_seen_fsid */
+               free_seen_fsid(seen_fsid_hash);
        }
-       close_file_or_dir(fd, dirstream);
 
        return ret;
 }
@@ -415,24 +439,32 @@ out:
  * - lowercase for enabling specific items in the output
  */
 static const char * const cmd_subvol_list_usage[] = {
-       "btrfs subvolume list [options] [-G [+|-]value] [-C [+|-]value] "
-       "[--sort=gen,ogen,rootid,path] <path>",
-       "List subvolumes (and snapshots)",
+       "btrfs subvolume list [options] <path>",
+       "List subvolumes and snapshots in the filesystem.",
        "",
-       "-p           print parent ID",
+       "Path filtering:",
+       "-o           print only subvolumes below specified path",
        "-a           print all the subvolumes in the filesystem and",
        "             distinguish absolute and relative path with respect",
        "             to the given <path>",
+       "",
+       "Field selection:",
+       "-p           print parent ID",
        "-c           print the ogeneration of the subvolume",
        "-g           print the generation of the subvolume",
-       "-o           print only subvolumes below specified path",
        "-u           print the uuid of subvolumes (and snapshots)",
        "-q           print the parent uuid of the snapshots",
        "-R           print the uuid of the received snapshots",
-       "-t           print the result as a table",
-       "-s           list snapshots only in the filesystem",
+       "",
+       "Type filtering:",
+       "-s           list only snapshots",
        "-r           list readonly subvolumes (including snapshots)",
        "-d           list deleted subvolumes that are not yet cleaned",
+       "",
+       "Other:",
+       "-t           print the result as a table",
+       "",
+       "Sorting:",
        "-G [+|-]value",
        "             filter the subvolumes by generation",
        "             (+value: >= value; -value: <= value; value: = value)",
@@ -455,15 +487,14 @@ static int cmd_subvol_list(int argc, char **argv)
        u64 top_id;
        int ret = -1, uerr = 0;
        char *subvol;
-       int is_tab_result = 0;
        int is_list_all = 0;
        int is_only_in_path = 0;
        DIR *dirstream = NULL;
+       enum btrfs_list_layout layout = BTRFS_LIST_LAYOUT_DEFAULT;
 
        filter_set = btrfs_list_alloc_filter_set();
        comparer_set = btrfs_list_alloc_comparer_set();
 
-       optind = 1;
        while(1) {
                int c;
                static const struct option long_options[] = {
@@ -498,7 +529,7 @@ static int cmd_subvol_list(int argc, char **argv)
                        is_only_in_path = 1;
                        break;
                case 't':
-                       is_tab_result = 1;
+                       layout = BTRFS_LIST_LAYOUT_TABLE;
                        break;
                case 's':
                        btrfs_list_setup_filter(&filter_set,
@@ -555,28 +586,26 @@ static int cmd_subvol_list(int argc, char **argv)
                }
        }
 
-       if (flags)
-               btrfs_list_setup_filter(&filter_set, BTRFS_LIST_FILTER_FLAGS,
-                                       flags);
-
        if (check_argc_exact(argc - optind, 1)) {
                uerr = 1;
                goto out;
        }
 
        subvol = argv[optind];
-       fd = open_file_or_dir(subvol, &dirstream);
+       fd = btrfs_open_dir(subvol, &dirstream, 1);
        if (fd < 0) {
                ret = -1;
-               fprintf(stderr, "ERROR: can't access '%s'\n", subvol);
+               error("can't access '%s'", subvol);
                goto out;
        }
 
+       if (flags)
+               btrfs_list_setup_filter(&filter_set, BTRFS_LIST_FILTER_FLAGS,
+                                       flags);
+
        ret = btrfs_list_get_path_rootid(fd, &top_id);
-       if (ret) {
-               fprintf(stderr, "ERROR: can't get rootid for '%s'\n", subvol);
+       if (ret)
                goto out;
-       }
 
        if (is_list_all)
                btrfs_list_setup_filter(&filter_set,
@@ -593,21 +622,15 @@ static int cmd_subvol_list(int argc, char **argv)
        btrfs_list_setup_print_column(BTRFS_LIST_TOP_LEVEL);
        btrfs_list_setup_print_column(BTRFS_LIST_PATH);
 
-       if (is_tab_result)
-               ret = btrfs_list_subvols_print(fd, filter_set, comparer_set,
-                               BTRFS_LIST_LAYOUT_TABLE,
-                               !is_list_all && !is_only_in_path, NULL);
-       else
-               ret = btrfs_list_subvols_print(fd, filter_set, comparer_set,
-                               BTRFS_LIST_LAYOUT_DEFAULT,
-                               !is_list_all && !is_only_in_path, NULL);
+       ret = btrfs_list_subvols_print(fd, filter_set, comparer_set,
+                       layout, !is_list_all && !is_only_in_path, NULL);
 
 out:
        close_file_or_dir(fd, dirstream);
        if (filter_set)
-               btrfs_list_free_filter_set(filter_set);
+               free(filter_set);
        if (comparer_set)
-               btrfs_list_free_comparer_set(comparer_set);
+               free(comparer_set);
        if (uerr)
                usage(cmd_subvol_list_usage);
        return !!ret;
@@ -640,7 +663,6 @@ static int cmd_subvol_snapshot(int argc, char **argv)
        struct btrfs_qgroup_inherit *inherit = NULL;
        DIR *dirstream1 = NULL, *dirstream2 = NULL;
 
-       optind = 1;
        memset(&args, 0, sizeof(args));
        while (1) {
                int c = getopt(argc, argv, "c:i:r");
@@ -686,17 +708,21 @@ static int cmd_subvol_snapshot(int argc, char **argv)
        retval = 1;     /* failure */
        res = test_issubvolume(subvol);
        if (res < 0) {
-               fprintf(stderr, "ERROR: error accessing '%s'\n", subvol);
+               error("cannot access subvolume %s: %s", subvol, strerror(-res));
                goto out;
        }
        if (!res) {
-               fprintf(stderr, "ERROR: '%s' is not a subvolume\n", subvol);
+               error("not a subvolume: %s", subvol);
                goto out;
        }
 
        res = test_isdir(dst);
+       if (res < 0 && res != -ENOENT) {
+               error("cannot access %s: %s", dst, strerror(-res));
+               goto out;
+       }
        if (res == 0) {
-               fprintf(stderr, "ERROR: '%s' exists and it is not a directory\n", dst);
+               error("'%s' exists and it is not a directory", dst);
                goto out;
        }
 
@@ -712,29 +738,23 @@ static int cmd_subvol_snapshot(int argc, char **argv)
        }
 
        if (!test_issubvolname(newname)) {
-               fprintf(stderr, "ERROR: incorrect snapshot name '%s'\n",
-                       newname);
+               error("invalid snapshot name '%s'", newname);
                goto out;
        }
 
        len = strlen(newname);
        if (len == 0 || len >= BTRFS_VOL_NAME_MAX) {
-               fprintf(stderr, "ERROR: snapshot name too long '%s'\n",
-                       newname);
+               error("snapshot name too long '%s'", newname);
                goto out;
        }
 
-       fddst = open_file_or_dir(dstdir, &dirstream1);
-       if (fddst < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", dstdir);
+       fddst = btrfs_open_dir(dstdir, &dirstream1, 1);
+       if (fddst < 0)
                goto out;
-       }
 
-       fd = open_file_or_dir(subvol, &dirstream2);
-       if (fd < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", dstdir);
+       fd = btrfs_open_dir(subvol, &dirstream2, 1);
+       if (fd < 0)
                goto out;
-       }
 
        if (readonly) {
                args.flags |= BTRFS_SUBVOL_RDONLY;
@@ -756,8 +776,7 @@ static int cmd_subvol_snapshot(int argc, char **argv)
        res = ioctl(fddst, BTRFS_IOC_SNAP_CREATE_V2, &args);
 
        if (res < 0) {
-               fprintf( stderr, "ERROR: cannot snapshot '%s' - %s\n",
-                       subvol, strerror(errno));
+               error("cannot snapshot '%s': %s", subvol, strerror(errno));
                goto out;
        }
 
@@ -788,26 +807,26 @@ static int cmd_subvol_get_default(int argc, char **argv)
        u64 default_id;
        DIR *dirstream = NULL;
 
-       if (check_argc_exact(argc, 2))
+       clean_args_no_options(argc, argv, cmd_subvol_get_default_usage);
+
+       if (check_argc_exact(argc - optind, 1))
                usage(cmd_subvol_get_default_usage);
 
        subvol = argv[1];
-       fd = open_file_or_dir(subvol, &dirstream);
-       if (fd < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", subvol);
+       fd = btrfs_open_dir(subvol, &dirstream, 1);
+       if (fd < 0)
                return 1;
-       }
 
        ret = btrfs_list_get_default_subvolume(fd, &default_id);
        if (ret) {
-               fprintf(stderr, "ERROR: can't perform the search - %s\n",
+               error("failed to look up default subvolume: %s",
                        strerror(errno));
                goto out;
        }
 
        ret = 1;
        if (default_id == 0) {
-               fprintf(stderr, "ERROR: 'default' dir item not found\n");
+               error("'default' dir item not found");
                goto out;
        }
 
@@ -832,15 +851,18 @@ static int cmd_subvol_get_default(int argc, char **argv)
                BTRFS_LIST_LAYOUT_DEFAULT, 1, NULL);
 
        if (filter_set)
-               btrfs_list_free_filter_set(filter_set);
+               free(filter_set);
 out:
        close_file_or_dir(fd, dirstream);
        return !!ret;
 }
 
 static const char * const cmd_subvol_set_default_usage[] = {
+       "btrfs subvolume set-default <subvolume>\n"
        "btrfs subvolume set-default <subvolid> <path>",
-       "Set the default subvolume of a filesystem",
+       "Set the default subvolume of the filesystem mounted as default.",
+       "The subvolume can be specified by its path,",
+       "or the pair of subvolume id and path to the filesystem.",
        NULL
 };
 
@@ -852,25 +874,51 @@ static int cmd_subvol_set_default(int argc, char **argv)
        char    *subvolid;
        DIR     *dirstream = NULL;
 
-       if (check_argc_exact(argc, 3))
+       clean_args_no_options(argc, argv, cmd_subvol_set_default_usage);
+
+       if (check_argc_min(argc - optind, 1) ||
+                       check_argc_max(argc - optind, 2))
                usage(cmd_subvol_set_default_usage);
 
-       subvolid = argv[1];
-       path = argv[2];
+       if (argc - optind == 1) {
+               /* path to the subvolume is specified */
+               path = argv[optind];
+
+               ret = test_issubvolume(path);
+               if (ret < 0) {
+                       error("stat error: %s", strerror(-ret));
+                       return 1;
+               } else if (!ret) {
+                       error("'%s' is not a subvolume", path);
+                       return 1;
+               }
 
-       objectid = arg_strtou64(subvolid);
+               fd = btrfs_open_dir(path, &dirstream, 1);
+               if (fd < 0)
+                       return 1;
 
-       fd = open_file_or_dir(path, &dirstream);
-       if (fd < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", path);
-               return 1;
+               ret = lookup_path_rootid(fd, &objectid);
+               if (ret) {
+                       error("unable to get subvol id: %s", strerror(-ret));
+                       close_file_or_dir(fd, dirstream);
+                       return 1;
+               }
+       } else {
+               /* subvol id and path to the filesystem are specified */
+               subvolid = argv[optind];
+               path = argv[optind + 1];
+               objectid = arg_strtou64(subvolid);
+
+               fd = btrfs_open_dir(path, &dirstream, 1);
+               if (fd < 0)
+                       return 1;
        }
 
        ret = ioctl(fd, BTRFS_IOC_DEFAULT_SUBVOL, &objectid);
        e = errno;
        close_file_or_dir(fd, dirstream);
        if (ret < 0) {
-               fprintf(stderr, "ERROR: unable to set a new default subvolume - %s\n",
+               error("unable to set a new default subvolume: %s",
                        strerror(e));
                return 1;
        }
@@ -891,31 +939,31 @@ static int cmd_subvol_find_new(int argc, char **argv)
        u64 last_gen;
        DIR *dirstream = NULL;
 
-       if (check_argc_exact(argc, 3))
+       clean_args_no_options(argc, argv, cmd_subvol_find_new_usage);
+
+       if (check_argc_exact(argc - optind, 2))
                usage(cmd_subvol_find_new_usage);
 
-       subvol = argv[1];
-       last_gen = arg_strtou64(argv[2]);
+       subvol = argv[optind];
+       last_gen = arg_strtou64(argv[optind + 1]);
 
        ret = test_issubvolume(subvol);
        if (ret < 0) {
-               fprintf(stderr, "ERROR: error accessing '%s'\n", subvol);
+               error("cannot access subvolume %s: %s", subvol, strerror(-ret));
                return 1;
        }
        if (!ret) {
-               fprintf(stderr, "ERROR: '%s' is not a subvolume\n", subvol);
+               error("not a subvolume: %s", subvol);
                return 1;
        }
 
-       fd = open_file_or_dir(subvol, &dirstream);
-       if (fd < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", subvol);
+       fd = btrfs_open_dir(subvol, &dirstream, 1);
+       if (fd < 0)
                return 1;
-       }
 
        ret = ioctl(fd, BTRFS_IOC_SYNC);
        if (ret < 0) {
-               fprintf(stderr, "ERROR: unable to fs-syncing '%s' - %s\n",
+               error("sync ioctl failed on '%s': %s",
                        subvol, strerror(errno));
                close_file_or_dir(fd, dirstream);
                return 1;
@@ -927,96 +975,96 @@ static int cmd_subvol_find_new(int argc, char **argv)
 }
 
 static const char * const cmd_subvol_show_usage[] = {
-       "btrfs subvolume show <subvol-path>",
-       "Show more information of the subvolume",
+       "btrfs subvolume show [options] <subvol-path>|<mnt>",
+       "Show more information about the subvolume",
+       "-r|--rootid   rootid of the subvolume",
+       "-u|--uuid     uuid of the subvolume",
+       "",
+       "If no option is specified, <subvol-path> will be shown, otherwise",
+       "the rootid or uuid are resolved relative to the <mnt> path.",
        NULL
 };
 
 static int cmd_subvol_show(int argc, char **argv)
 {
        struct root_info get_ri;
-       struct btrfs_list_filter_set *filter_set;
+       struct btrfs_list_filter_set *filter_set = NULL;
        char tstr[256];
        char uuidparse[BTRFS_UUID_UNPARSED_SIZE];
-       char *fullpath = NULL, *svpath = NULL, *mnt = NULL;
+       char *fullpath = NULL;
        char raw_prefix[] = "\t\t\t\t";
-       u64 sv_id;
-       int fd = -1, mntfd = -1;
+       int fd = -1;
        int ret = 1;
-       DIR *dirstream1 = NULL, *dirstream2 = NULL;
+       DIR *dirstream1 = NULL;
+       int by_rootid = 0;
+       int by_uuid = 0;
+       u64 rootid_arg;
+       u8 uuid_arg[BTRFS_UUID_SIZE];
 
-       if (check_argc_exact(argc, 2))
-               usage(cmd_subvol_show_usage);
-
-       fullpath = realpath(argv[1], NULL);
-       if (!fullpath) {
-               fprintf(stderr, "ERROR: finding real path for '%s', %s\n",
-                       argv[1], strerror(errno));
-               goto out;
-       }
+       while (1) {
+               int c;
+               static const struct option long_options[] = {
+                       { "rootid", required_argument, NULL, 'r'},
+                       { "uuid", required_argument, NULL, 'u'},
+                       { NULL, 0, NULL, 0 }
+               };
 
-       ret = test_issubvolume(fullpath);
-       if (ret < 0) {
-               fprintf(stderr, "ERROR: error accessing '%s'\n", fullpath);
-               goto out;
-       }
-       if (!ret) {
-               fprintf(stderr, "ERROR: '%s' is not a subvolume\n", fullpath);
-               ret = 1;
-               goto out;
-       }
+               c = getopt_long(argc, argv, "r:u:", long_options, NULL);
+               if (c < 0)
+                       break;
 
-       ret = find_mount_root(fullpath, &mnt);
-       if (ret < 0) {
-               fprintf(stderr, "ERROR: find_mount_root failed on '%s': "
-                               "%s\n", fullpath, strerror(-ret));
-               goto out;
-       }
-       if (ret > 0) {
-               fprintf(stderr,
-                       "ERROR: %s doesn't belong to btrfs mount point\n",
-                       fullpath);
-               goto out;
+               switch (c) {
+               case 'r':
+                       rootid_arg = arg_strtou64(optarg);
+                       by_rootid = 1;
+                       break;
+               case 'u':
+                       uuid_parse(optarg, uuid_arg);
+                       by_uuid = 1;
+                       break;
+               default:
+                       usage(cmd_subvol_show_usage);
+               }
        }
-       ret = 1;
-       svpath = get_subvol_name(mnt, fullpath);
 
-       fd = open_file_or_dir(fullpath, &dirstream1);
-       if (fd < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", fullpath);
-               goto out;
-       }
+       if (check_argc_exact(argc - optind, 1))
+               usage(cmd_subvol_show_usage);
 
-       ret = btrfs_list_get_path_rootid(fd, &sv_id);
-       if (ret) {
-               fprintf(stderr, "ERROR: can't get rootid for '%s'\n",
-                       fullpath);
-               goto out;
+       if (by_rootid && by_uuid) {
+               error(
+               "options --rootid and --uuid cannot be used at the same time");
+               usage(cmd_subvol_show_usage);
        }
 
-       mntfd = open_file_or_dir(mnt, &dirstream2);
-       if (mntfd < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", mnt);
+       memset(&get_ri, 0, sizeof(get_ri));
+       fullpath = realpath(argv[optind], NULL);
+       if (!fullpath) {
+               error("cannot find real path for '%s': %s",
+                       argv[optind], strerror(errno));
                goto out;
        }
 
-       if (sv_id == BTRFS_FS_TREE_OBJECTID) {
-               printf("%s is btrfs root\n", fullpath);
-               goto out;
+       if (by_rootid) {
+               ret = get_subvol_info_by_rootid(fullpath, &get_ri, rootid_arg);
+       } else if (by_uuid) {
+               ret = get_subvol_info_by_uuid(fullpath, &get_ri, uuid_arg);
+       } else {
+               ret = get_subvol_info(fullpath, &get_ri);
        }
 
-       memset(&get_ri, 0, sizeof(get_ri));
-       get_ri.root_id = sv_id;
-
-       ret = btrfs_get_subvol(mntfd, &get_ri);
        if (ret) {
-               fprintf(stderr, "ERROR: can't find '%s'\n",
-                       svpath);
-               goto out;
+               if (ret < 0) {
+                       error("Failed to get subvol info %s: %s",
+                                       fullpath, strerror(-ret));
+               } else {
+                       error("Failed to get subvol info %s: %d",
+                                       fullpath, ret);
+               }
+               return ret;
        }
 
        /* print the info */
-       printf("%s\n", fullpath);
+       printf("%s\n", get_ri.full_path);
        printf("\tName: \t\t\t%s\n", get_ri.name);
 
        if (uuid_is_null(get_ri.uuid))
@@ -1063,19 +1111,23 @@ static int cmd_subvol_show(int argc, char **argv)
        btrfs_list_setup_filter(&filter_set, BTRFS_LIST_FILTER_BY_PARENT,
                                (u64)(unsigned long)get_ri.uuid);
        btrfs_list_setup_print_column(BTRFS_LIST_PATH);
+
+       fd = open_file_or_dir(fullpath, &dirstream1);
+       if (fd < 0) {
+               fprintf(stderr, "ERROR: can't access '%s'\n", fullpath);
+               goto out;
+       }
        btrfs_list_subvols_print(fd, filter_set, NULL, BTRFS_LIST_LAYOUT_RAW,
                        1, raw_prefix);
 
+out:
        /* clean up */
        free(get_ri.path);
        free(get_ri.name);
        free(get_ri.full_path);
-       btrfs_list_free_filter_set(filter_set);
+       free(filter_set);
 
-out:
        close_file_or_dir(fd, dirstream1);
-       close_file_or_dir(mntfd, dirstream2);
-       free(mnt);
        free(fullpath);
        return !!ret;
 }
@@ -1165,12 +1217,13 @@ again:
  * Enumerate all dead subvolumes that exist in the filesystem.
  * Fill @ids and reallocate to bigger size if needed.
  */
-static int enumerate_dead_subvols(int fd, int count, u64 **ids)
+static int enumerate_dead_subvols(int fd, u64 **ids)
 {
        int ret;
        struct btrfs_ioctl_search_args args;
        struct btrfs_ioctl_search_key *sk = &args.key;
        int idx = 0;
+       int count = 0;
 
        memset(&args, 0, sizeof(args));
 
@@ -1185,6 +1238,7 @@ static int enumerate_dead_subvols(int fd, int count, u64 **ids)
        sk->max_transid = (u64)-1;
        sk->nr_items = 4096;
 
+       *ids = NULL;
        while (1) {
                struct btrfs_ioctl_search_header *sh;
                unsigned long off;
@@ -1202,24 +1256,26 @@ static int enumerate_dead_subvols(int fd, int count, u64 **ids)
                        sh = (struct btrfs_ioctl_search_header*)(args.buf + off);
                        off += sizeof(*sh);
 
-                       if (sh->type == BTRFS_ORPHAN_ITEM_KEY) {
-                               (*ids)[idx] = sh->offset;
-                               idx++;
+                       if (btrfs_search_header_type(sh)
+                           == BTRFS_ORPHAN_ITEM_KEY) {
                                if (idx >= count) {
                                        u64 *newids;
 
                                        count += SUBVOL_ID_BATCH;
-                                       newids = (u64*)realloc(*ids, count);
+                                       newids = (u64*)realloc(*ids,
+                                                       count * sizeof(u64));
                                        if (!newids)
                                                return -ENOMEM;
                                        *ids = newids;
                                }
+                               (*ids)[idx] = btrfs_search_header_offset(sh);
+                               idx++;
                        }
-                       off += sh->len;
+                       off += btrfs_search_header_len(sh);
 
-                       sk->min_objectid = sh->objectid;
-                       sk->min_type = sh->type;
-                       sk->min_offset = sh->offset;
+                       sk->min_objectid = btrfs_search_header_objectid(sh);
+                       sk->min_type = btrfs_search_header_type(sh);
+                       sk->min_offset = btrfs_search_header_offset(sh);
                }
                if (sk->min_offset < (u64)-1)
                        sk->min_offset++;
@@ -1244,7 +1300,6 @@ static int cmd_subvol_sync(int argc, char **argv)
        int id_count;
        int sleep_interval = 1;
 
-       optind = 1;
        while (1) {
                int c = getopt(argc, argv, "s:");
 
@@ -1253,11 +1308,9 @@ static int cmd_subvol_sync(int argc, char **argv)
 
                switch (c) {
                case 's':
-                       sleep_interval = atoi(argv[optind]);
+                       sleep_interval = atoi(optarg);
                        if (sleep_interval < 1) {
-                               fprintf(stderr,
-                                       "ERROR: invalid sleep interval %s\n",
-                                       argv[optind]);
+                               error("invalid sleep interval %s", optarg);
                                ret = 1;
                                goto out;
                        }
@@ -1270,9 +1323,8 @@ static int cmd_subvol_sync(int argc, char **argv)
        if (check_argc_min(argc - optind, 1))
                usage(cmd_subvol_sync_usage);
 
-       fd = open_file_or_dir(argv[optind], &dirstream);
+       fd = btrfs_open_dir(argv[optind], &dirstream, 1);
        if (fd < 0) {
-               fprintf(stderr, "ERROR: can't access '%s'\n", argv[optind]);
                ret = 1;
                goto out;
        }
@@ -1280,16 +1332,9 @@ static int cmd_subvol_sync(int argc, char **argv)
 
        id_count = argc - optind;
        if (!id_count) {
-               id_count = SUBVOL_ID_BATCH;
-               ids = (u64*)malloc(id_count * sizeof(u64));
-               if (!ids) {
-                       fprintf(stderr, "ERROR: not enough memory\n");
-                       ret = 1;
-                       goto out;
-               }
-               id_count = enumerate_dead_subvols(fd, id_count, &ids);
+               id_count = enumerate_dead_subvols(fd, &ids);
                if (id_count < 0) {
-                       fprintf(stderr, "ERROR: can't enumerate dead subvolumes: %s\n",
+                       error("can't enumerate dead subvolumes: %s",
                                        strerror(-id_count));
                        ret = 1;
                        goto out;
@@ -1301,7 +1346,7 @@ static int cmd_subvol_sync(int argc, char **argv)
        } else {
                ids = (u64*)malloc(id_count * sizeof(u64));
                if (!ids) {
-                       fprintf(stderr, "ERROR: not enough memory\n");
+                       error("not enough memory");
                        ret = 1;
                        goto out;
                }
@@ -1314,17 +1359,13 @@ static int cmd_subvol_sync(int argc, char **argv)
                        errno = 0;
                        id = strtoull(arg, NULL, 10);
                        if (errno < 0) {
-                               fprintf(stderr,
-                                       "ERROR: unrecognized subvolume id %s\n",
-                                       arg);
+                               error("unrecognized subvolume id %s", arg);
                                ret = 1;
                                goto out;
                        }
                        if (id < BTRFS_FIRST_FREE_OBJECTID
                                        || id > BTRFS_LAST_FREE_OBJECTID) {
-                               fprintf(stderr,
-                                       "ERROR: subvolume id %s out of range\n",
-                                       arg);
+                               error("subvolume id %s out of range", arg);
                                ret = 1;
                                goto out;
                        }