On Fri, Jun 29, 2012 at 06:00:38PM +0800, Liu Bo wrote:
> We want 'btrfs subvolume list' to act as 'ls', which means that
> we can not only list out all the subvolumes we have, but also list
> each single one.
>
> So this patch add 's' option to show a single one:
>
> $ ./btrfs sub list /mnt/btrfs/
> ID 256 top level 5 path subvol (Readonly,)
> ID 257 top level 5 path snapshot
> ID 258 top level 5 path subvol2
> ID 259 top level 5 path subvol2/subvol3
>
> $ ./btrfs sub list -s /mnt/btrfs/subvol
> ID 256 top level 5 path subvol (Readonly,)
suggestions and comments:
1) show the subvolume flags only if an option is given, similar to -p
(to show parent subvol),
2) move the flags before the subvolume path -- it is of a
variable length and it's a bit easier (but not reliable) to parse it
from scripts
sidenote: 'find /mnt -inum 256 -print0' will list all subvolumes in a
way that's resitent to funny characters in the path, but is slow as it
has to traverse the filesystem (and 'find' does not support a true
breadth-first-search, needs to be iterated with -mindepth/maxdepth).
the 'subvol list' command could mimic the -print0 and print the
subvolume paths terminated by '\0'.
3) drop the , if there's only one subvol property
4) the '-s' option on the mountpoint does not show anything, though I
would expect that, eg when the mountpoint is a subvolume
--
one comment to code below
david
>
> Signed-off-by: Liu Bo <liubo2009@xxxxxxxxxxxxxx>
> ---
> btrfs-list.c | 41 ++++++++++++++++++++++++++++++++++++++++-
> cmds-subvolume.c | 15 ++++++++++-----
> 2 files changed, 50 insertions(+), 6 deletions(-)
>
> diff --git a/btrfs-list.c b/btrfs-list.c
> index f1baa52..3e79239 100644
> --- a/btrfs-list.c
> +++ b/btrfs-list.c
> @@ -312,6 +312,30 @@ static int lookup_ino_path(int fd, struct root_info *ri)
> return 0;
> }
>
> +/*
> + * helper function for getting the root which the file is belonged to.
> + */
> +static int lookup_ino_rootid(int fd, u64 *rootid)
> +{
> + struct btrfs_ioctl_ino_lookup_args args;
> + int ret, e;
> +
> + memset(&args, 0, sizeof(args));
> + args.treeid = 0;
> + args.objectid = BTRFS_FIRST_FREE_OBJECTID;
> +
> + ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args);
> + e = errno;
> + if (ret) {
> + fprintf(stderr, "ERROR: Failed to lookup root id - %s\n",
> + strerror(e));
> + return ret;
> + }
> +
> + *rootid = args.treeid;
> + return 0;
> +}
> +
> /* finding the generation for a given path is a two step process.
> * First we use the inode loookup routine to find out the root id
> *
> @@ -704,11 +728,12 @@ int subvol_get_set_flags(int fd, int set, u64 flags, u64 root_id)
> return 0;
> }
>
> -int list_subvols(int fd, int print_parent, int get_default)
> +int list_subvols(int fd, int print_parent, int print_self, int get_default)
> {
> struct root_lookup root_lookup;
> struct rb_node *n;
> int ret;
> + u64 subvolid = 0;
>
> ret = __list_subvol_search(fd, &root_lookup);
> if (ret) {
> @@ -725,6 +750,9 @@ int list_subvols(int fd, int print_parent, int get_default)
> if (ret < 0)
> return ret;
>
> + if (print_self)
> + lookup_ino_rootid(fd, &subvolid);
you should probably check the return value
> +
> /* now that we have all the subvol-relative paths filled in,
> * we have to string the subvols together so that we can get
> * a path all the way back to the FS root
> @@ -739,6 +767,14 @@ int list_subvols(int fd, int print_parent, int get_default)
> entry = rb_entry(n, struct root_info, rb_node);
> resolve_root(&root_lookup, entry, &root_id, &parent_id,
> &level, &path);
> +
> + /* print this subvolume only */
> + if (print_self && subvolid != root_id) {
> + free(path);
> + n = rb_prev(n);
> + continue;
> + }
> +
> if (print_parent) {
> printf("ID %llu parent %llu top level %llu path %s",
> (unsigned long long)root_id,
> @@ -753,6 +789,9 @@ int list_subvols(int fd, int print_parent, int get_default)
> printf("\n");
> free(path);
> n = rb_prev(n);
> +
> + if (print_self)
> + break;
> }
>
> return ret;
> diff --git a/cmds-subvolume.c b/cmds-subvolume.c
> index 8783e67..f779b78 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 print_self, int get_default);
> int find_updated_files(int fd, u64 root_id, u64 oldest_gen);
> int subvol_get_set_flags(int fd, int set, u64 flags, u64 root_id);
>
> @@ -218,10 +218,11 @@ 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 [-ps] <path>",
> "List subvolumes (and snapshots)",
> "",
> "-p print parent ID",
> + "-s print this subvolume only",
> NULL
> };
>
> @@ -230,11 +231,12 @@ static int cmd_subvol_list(int argc, char **argv)
> int fd;
> int ret;
> int print_parent = 0;
> + int print_self = 0;
> char *subvol;
>
> optind = 1;
> while(1) {
> - int c = getopt(argc, argv, "p");
> + int c = getopt(argc, argv, "ps");
> if (c < 0)
> break;
>
> @@ -242,6 +244,9 @@ static int cmd_subvol_list(int argc, char **argv)
> case 'p':
> print_parent = 1;
> break;
> + case 's':
> + print_self = 1;
> + break;
> default:
> usage(cmd_subvol_list_usage);
> }
> @@ -267,7 +272,7 @@ 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, print_self, 0);
> if (ret)
> return 19;
> return 0;
> @@ -426,7 +431,7 @@ 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, 0, 1);
> if (ret)
> return 19;
> return 0;
> --
> 1.6.5.2
>
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