This is the complement to the corresponding kernel patch that adds support for permanent options.
NOTE: Like the corresponding kernel patch, this is a WIP with the goal o gathering feedback. Signed-off-by: Filipe David Borba Manana <[email protected]> --- btrfstune.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- ctree.h | 8 +++++ print-tree.c | 9 +++++ 3 files changed, 120 insertions(+), 2 deletions(-) diff --git a/btrfstune.c b/btrfstune.c index 4db1767..b3d3e57 100644 --- a/btrfstune.c +++ b/btrfstune.c @@ -97,12 +97,100 @@ int enable_skinny_metadata(struct btrfs_root *root) return 0; } +static int set_persistent_mount_options(struct btrfs_root *root, + const char *options) +{ + int ret; + struct btrfs_trans_handle *trans = NULL; + struct btrfs_path *path; + struct btrfs_key key, location; + struct extent_buffer *leaf; + struct btrfs_dir_item *dir_item; + struct btrfs_disk_key disk_key; + struct btrfs_root *tree_root = root->fs_info->tree_root; + unsigned long data_ptr; + u32 data_size, data_len; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + trans = btrfs_start_transaction(root, 1); + if (!trans) { + ret = -ENOMEM; + goto out; + } + + key.objectid = BTRFS_PERSISTENT_OPTIONS_OBJECTID; + key.type = 0; + key.offset = 0; + + ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1); + if (ret < 0) + goto out; + if (!ret) { + char *buf; + + leaf = path->nodes[0]; + dir_item = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_dir_item); + buf = (char *) malloc(btrfs_dir_data_len(leaf, dir_item)); + if (!buf) { + ret = -ENOMEM; + goto out; + } + read_extent_buffer(leaf, buf, + (unsigned long)((char *)(dir_item + 1)), + btrfs_dir_data_len(leaf, dir_item)); + printf("Current persistent options: %.*s\n", + btrfs_dir_data_len(leaf, dir_item), buf); + free(buf); + ret = btrfs_del_item(trans, tree_root, path); + if (ret) + goto out; + } + + btrfs_release_path(root, path); + + data_len = strlen(options); + data_size = sizeof(*dir_item) + data_len; + ret = btrfs_insert_empty_item(trans, tree_root, path, &key, data_size); + if (ret) + goto out; + + leaf = path->nodes[0]; + dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item); + + memset(&location, 0, sizeof(location)); + btrfs_cpu_key_to_disk(&disk_key, &location); + btrfs_set_dir_item_key(leaf, dir_item, &disk_key); + btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_UNKNOWN); + btrfs_set_dir_name_len(leaf, dir_item, 0); + btrfs_set_dir_data_len(leaf, dir_item, data_len); + data_ptr = (unsigned long)((char *)(dir_item + 1)); + + write_extent_buffer(leaf, options, data_ptr, data_len); + btrfs_mark_buffer_dirty(leaf); + +out: + if (!ret && trans) + ret = btrfs_commit_transaction(trans, root); + else if (trans) + btrfs_free_transaction(root, trans); + btrfs_free_path(path); + if (!ret) + printf("New persistent options: %s\n", options); + + return ret; +} + static void print_usage(void) { fprintf(stderr, "usage: btrfstune [options] device\n"); fprintf(stderr, "\t-S value\tenable/disable seeding\n"); fprintf(stderr, "\t-r \t\tenable extended inode refs\n"); - fprintf(stderr, "\t-x enable skinny metadata extent refs\n"); + fprintf(stderr, "\t-x \t\tenable skinny metadata extent refs\n"); + fprintf(stderr, "\t-o options\tset persistent mount options\n"); } int main(int argc, char *argv[]) @@ -114,9 +202,10 @@ int main(int argc, char *argv[]) int seeding_value = 0; int skinny_flag = 0; int ret; + char *options = NULL; while(1) { - int c = getopt(argc, argv, "S:rx"); + int c = getopt(argc, argv, "S:rxo:"); if (c < 0) break; switch(c) { @@ -130,6 +219,9 @@ int main(int argc, char *argv[]) case 'x': skinny_flag = 1; break; + case 'o': + options = optarg; + break; default: print_usage(); return 1; @@ -171,6 +263,15 @@ int main(int argc, char *argv[]) success++; } + if (options) { + ret = set_persistent_mount_options(root, options); + if (ret) + fprintf(stderr, + "Error setting persistent options: %d\n", ret); + else + success++; + } + if (success > 0) { ret = 0; } else { diff --git a/ctree.h b/ctree.h index 0b0d701..8255661 100644 --- a/ctree.h +++ b/ctree.h @@ -102,6 +102,14 @@ struct btrfs_free_space_ctl; */ #define BTRFS_FREE_INO_OBJECTID -12ULL +/* + * Item that stores permanent mount options. These options + * have effect if they are not specified as well at mount + * time (that is, if a permanent option is also specified at + * mount time, the later wins). + */ +#define BTRFS_PERSISTENT_OPTIONS_OBJECTID -13ULL + /* dummy objectid represents multiple objectids */ #define BTRFS_MULTIPLE_OBJECTIDS -255ULL diff --git a/print-tree.c b/print-tree.c index aae47a9..4cb7af6 100644 --- a/print-tree.c +++ b/print-tree.c @@ -585,6 +585,9 @@ static void print_objectid(u64 objectid, u8 type) case BTRFS_MULTIPLE_OBJECTIDS: printf("MULTIPLE"); break; + case BTRFS_PERSISTENT_OPTIONS_OBJECTID: + printf("PERSISTENT_OPTIONS"); + break; case (u64)-1: printf("-1"); break; @@ -849,6 +852,12 @@ void btrfs_print_leaf(struct btrfs_root *root, struct extent_buffer *l) case BTRFS_DEV_STATS_KEY: printf("\t\tdevice stats\n"); break; + case 0: + if (objectid == BTRFS_PERSISTENT_OPTIONS_OBJECTID) { + di = btrfs_item_ptr(l, i, struct btrfs_dir_item); + print_dir_item(l, item, di); + } + break; }; fflush(stdout); } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
