Hi Bo, On 08/02/2012 12:13 PM, zhoubo wrote: > From: Zhou Bo <[email protected]> > > This patch enhances btrfs subvol list to show read-only snapshots. > You can use the -r option showing read-only snapshots, for example: > btrfs subvolume list -r <path>
Please elaborate this sentence: if I read correctly your code, the switch '-r' shows *only* the read only subvolume. It is no clear from your description > > Signed-off-by: Zhou Bo <[email protected]> > --- > btrfs-list.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++------ > cmds-subvolume.c | 15 ++++++++---- > ctree.h | 2 + > 3 files changed, 72 insertions(+), 13 deletions(-) > > diff --git a/btrfs-list.c b/btrfs-list.c > index 693d241..9c10b9e 100644 > --- a/btrfs-list.c > +++ b/btrfs-list.c > @@ -608,7 +608,46 @@ out: > return 0; > } > > -static int __list_subvol_search(int fd, struct root_lookup *root_lookup) > +static int is_readonly_subvol(int fd, u64 objectid) > +{ > + int ret; > + struct btrfs_ioctl_search_args args; > + struct btrfs_ioctl_search_key *sk = &args.key; > + struct btrfs_ioctl_search_header *sh; > + unsigned long off = 0; > + int found = 0; > + struct btrfs_root_item *item; > + > + memset(&args, 0, sizeof(args)); > + > + /* search in the tree of tree roots */ > + sk->tree_id = BTRFS_ROOT_TREE_OBJECTID; > + sk->min_objectid = objectid; > + sk->max_objectid = objectid; > + sk->max_type = BTRFS_ROOT_ITEM_KEY; > + sk->min_type = BTRFS_ROOT_ITEM_KEY; > + sk->max_offset = (u64)-1; > + sk->max_transid = (u64)-1; > + sk->nr_items = 1; > + ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args); > + if (ret < 0) > + return ret; > + if (sk->nr_items == 0) { > + errno = -ENOENT; > + found = -1; > + goto out; > + } > + sh = (struct btrfs_ioctl_search_header *)args.buf; > + off += sizeof(*sh); > + item = (struct btrfs_root_item *)(args.buf + off); > + if (item->flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) > + found = 1; > +out: > + return found; > +} > + > +static int __list_subvol_search(int fd, struct root_lookup *root_lookup, > + int list_ro) > { > int ret; > struct btrfs_ioctl_search_args args; > @@ -668,9 +707,23 @@ static int __list_subvol_search(int fd, struct > root_lookup *root_lookup) > name_len = btrfs_stack_root_ref_name_len(ref); > name = (char *)(ref + 1); > dir_id = btrfs_stack_root_ref_dirid(ref); > - > - add_root(root_lookup, sh->objectid, sh->offset, > - dir_id, name, name_len); > + if (list_ro) { > + int subvol_readonly = > + is_readonly_subvol(fd, > + sh->objectid); > + if (subvol_readonly < 0) { > + return subvol_readonly; > + } else if (subvol_readonly) { > + add_root(root_lookup, > + sh->objectid, > + sh->offset, dir_id, > + name, name_len); > + } > + } else { > + add_root(root_lookup, sh->objectid, > + sh->offset, dir_id, > + name, name_len); > + } > } > > off += sh->len; > @@ -719,7 +772,7 @@ static int __list_subvol_fill_paths(int fd, struct > root_lookup *root_lookup) > return 0; > } > > -int list_subvols(int fd, int print_parent, int get_default) > +int list_subvols(int fd, int print_parent, int get_default, int list_ro) > { > struct root_lookup root_lookup; > struct rb_node *n; > @@ -745,7 +798,7 @@ int list_subvols(int fd, int print_parent, int > get_default) > } > } > > - ret = __list_subvol_search(fd, &root_lookup); > + ret = __list_subvol_search(fd, &root_lookup, list_ro); > if (ret) { > fprintf(stderr, "ERROR: can't perform the search - %s\n", > strerror(errno)); > @@ -788,7 +841,6 @@ int list_subvols(int fd, int print_parent, int > get_default) > (unsigned long long)entry->root_id, > (unsigned long long)level, path); > } > - > free(path); > n = rb_prev(n); > } > @@ -983,7 +1035,7 @@ char *path_for_root(int fd, u64 root) > char *ret_path = NULL; > int ret; > > - ret = __list_subvol_search(fd, &root_lookup); > + ret = __list_subvol_search(fd, &root_lookup, 0); > if (ret < 0) > return ERR_PTR(ret); > > diff --git a/cmds-subvolume.c b/cmds-subvolume.c > index 3508ce6..791ac3f 100644 > --- a/cmds-subvolume.c > +++ b/cmds-subvolume.c > @@ -30,7 +30,7 @@ > #include "commands.h" > > /* btrfs-list.c */ > -int list_subvols(int fd, int print_parent, int get_default); > +int list_subvols(int fd, int print_parent, int get_default, int list_ro); > int find_updated_files(int fd, u64 root_id, u64 oldest_gen); Does make sense to put these declaration in an header file ? > > static const char * const subvolume_cmd_group_usage[] = { > @@ -219,10 +219,11 @@ static int cmd_subvol_delete(int argc, char **argv) > } > > static const char * const cmd_subvol_list_usage[] = { > - "btrfs subvolume list [-p] <path>", > + "btrfs subvolume list [-pr] <path>", > "List subvolumes (and snapshots)", > "", > "-p print parent ID", > + "-r list read-only snapshots", Please, if you change the btrfs command update the man page too > NULL > }; > > @@ -231,15 +232,19 @@ static int cmd_subvol_list(int argc, char **argv) > int fd; > int ret; > int print_parent = 0; > + int list_ro = 0; > char *subvol; > > optind = 1; > while(1) { > - int c = getopt(argc, argv, "p"); > + int c = getopt(argc, argv, "pr"); > if (c < 0) > break; > > switch(c) { > + case 'r': > + list_ro = 1; > + break; > case 'p': > print_parent = 1; > break; > @@ -268,7 +273,7 @@ static int cmd_subvol_list(int argc, char **argv) > fprintf(stderr, "ERROR: can't access '%s'\n", subvol); > return 12; > } > - ret = list_subvols(fd, print_parent, 0); > + ret = list_subvols(fd, print_parent, 0, list_ro); > if (ret) > return 19; > return 0; > @@ -428,7 +433,7 @@ static int cmd_subvol_get_default(int argc, char **argv) > fprintf(stderr, "ERROR: can't access '%s'\n", subvol); > return 12; > } > - ret = list_subvols(fd, 0, 1); > + ret = list_subvols(fd, 0, 1, 0); > if (ret) > return 19; > return 0; > diff --git a/ctree.h b/ctree.h > index 71e387b..12da31a 100644 > --- a/ctree.h > +++ b/ctree.h > @@ -138,6 +138,8 @@ static int btrfs_csum_sizes[] = { 4, 0 }; > #define BTRFS_FT_XATTR 8 > #define BTRFS_FT_MAX 9 > > +#define BTRFS_ROOT_SUBVOL_RDONLY (1ULL << 0) > + > /* > * the key defines the order in the tree, and so it also defines (optimal) > * block layout. objectid corresonds to the inode number. 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