> -----Original Message----- > From: Goffredo Baroncelli <kreijack@xxxxxxxxx> > [mailto:kreijack@xxxxxxxxx] > Sent: Monday, July 11, 2011 8:03 PM > To: Zhong, Xin > Cc: linux-btrfs@xxxxxxxxxxxxxxx > Subject: R: [PATCH V2] Btrfs-progs: add "btrfs subvolume get-default" > subcommand > > >----Messaggio originale---- > >Da: xin.zhong@xxxxxxxxx > >Data: 11/07/2011 10.56 > >A: <linux-btrfs@xxxxxxxxxxxxxxx> > >Cc: <xin.zhong@xxxxxxxxx> > >Ogg: [PATCH V2] Btrfs-progs: add "btrfs subvolume get- > default" > subcommand > > > >Add subcommand to get the default subvolume of btrfs filesystem > > > >Reported-by: Yang, Yi <yi.y.yang@xxxxxxxxx> > >Signed-off-by: Zhong, Xin <xin.zhong@xxxxxxxxx> > >--- > > btrfs-list.c | 57 > +++++++++++++++++++++++++++++++++++++++++++++++++++++++-- > > btrfs.c | 3 +++ > > btrfs_cmds.c | 31 ++++++++++++++++++++++++++++++- > > btrfs_cmds.h | 3 ++- > > 4 files changed, 90 insertions(+), 4 deletions(-) > > please update the man page too. > > > > >diff --git a/btrfs-list.c b/btrfs-list.c > >index 93766a8..aa6a9b4 100644 > >--- a/btrfs-list.c > >+++ b/btrfs-list.c > >@@ -536,7 +536,7 @@ build: > > return full; > [...] > >+ /* search dir item */ > >+ sk->max_type = BTRFS_DIR_ITEM_KEY; > >+ sk->min_type = BTRFS_DIR_ITEM_KEY; > >+ > >+ sk->max_objectid = BTRFS_ROOT_TREE_DIR_OBJECTID; > >+ sk->min_objectid = BTRFS_ROOT_TREE_DIR_OBJECTID; > >+ sk->max_offset = (u64)-1; > >+ sk->max_transid = (u64)-1; > >+ > [...] > >+ /* go through each item to find dir item named "default" */ > >+ for (i = 0; i < sk->nr_items; i++) { > >+ sh = (struct btrfs_ioctl_search_header *)(args.buf + > >+ off); > >+ off += sizeof(*sh); > >+ if (sh->type == BTRFS_DIR_ITEM_KEY) { > >+ di = (struct btrfs_dir_item *)(args.buf + off); > >+ name_len = le16_to_cpu(di->name_len); > >+ name = (char *)di + sizeof(struct > btrfs_dir_item); > >+ if (!strncmp("default", name, name_len)) { > >+ subvol_id = btrfs_disk_key_objectid( > >+ &di->location); > >+ break; > >+ } > >+ } > >+ > >+ off += sh->len; > >+ } > > I am not familiar with the "default subvolume key", but are you sure > that the > key is always in the first set of returned keys ? > It seems there's not too much dir item in the root tree. In fact, I only see it used for for default subvolume in the root tree. So it should be enough. > >+ } > >+ > > /* 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 > >@@ -650,7 +698,12 @@ int list_subvols(int fd) > > while (n) { > > struct root_info *entry; > > entry = rb_entry(n, struct root_info, rb_node); > >- resolve_root(&root_lookup, entry); > >+ if(!get_default) > >+ resolve_root(&root_lookup, entry); > >+ /* we only want the default subvolume */ > >+ else if(subvol_id == entry->root_id) > >+ resolve_root(&root_lookup, entry); > >+ > > What happens if there no is a default subvolume (for example a very old > btrfs > filesystem, and/or after removing the "default" subvolume) ? > I suggest to handle this case printing something like "No default > subvolume > found" > If there's no default subvolume, the output is empty. Just the same as when you use "btrfs subvolume list" and there's no subvolume at all. Thanks for all the review! > > BR > G.Baroncelli > > > n = rb_prev(n); > > } > > > >diff --git a/btrfs.c b/btrfs.c > >index 46314cf..6b73f88 100644 > >--- a/btrfs.c > >+++ b/btrfs.c > >@@ -73,6 +73,9 @@ static struct Command commands[] = { > > "Set the subvolume of the filesystem <path> which will be > mounted\n" > > "as default." > > }, > >+ { do_get_default_subvol, 1, "subvolume get-default", "<path>\n" > >+ "Get the default subvolume of a filesystem." > >+ }, > > { do_fssync, 1, > > "filesystem sync", "<path>\n" > > "Force a sync on the filesystem <path>." > >diff --git a/btrfs_cmds.c b/btrfs_cmds.c > >index 8031c58..11c56f6 100644 > >--- a/btrfs_cmds.c > >+++ b/btrfs_cmds.c > >@@ -301,7 +301,7 @@ int do_subvol_list(int argc, char **argv) > > fprintf(stderr, "ERROR: can't access '%s'\n", subvol); > > return 12; > > } > >- ret = list_subvols(fd); > >+ ret = list_subvols(fd, 0); > > if (ret) > > return 19; > > return 0; > >@@ -834,6 +834,35 @@ int do_set_default_subvol(int nargs, char **argv) > > return 0; > > } > > > >+int do_get_default_subvol(int nargs, char **argv) > >+{ > >+ int fd; > >+ int ret; > >+ char *subvol; > >+ > >+ subvol = argv[1]; > >+ > >+ ret = test_issubvolume(subvol); > >+ if (ret < 0) { > >+ fprintf(stderr, "ERROR: error accessing '%s'\n", subvol); > >+ return 12; > >+ } > >+ if (!ret) { > >+ fprintf(stderr, "ERROR: '%s' is not a subvolume\n", subvol); > >+ return 13; > >+ } > >+ > >+ fd = open_file_or_dir(subvol); > >+ if (fd < 0) { > >+ fprintf(stderr, "ERROR: can't access '%s'\n", subvol); > >+ return 12; > >+ } > >+ ret = list_subvols(fd, 1); > >+ if (ret) > >+ return 19; > >+ return 0; > >+} > >+ > > int do_df_filesystem(int nargs, char **argv) > > { > > struct btrfs_ioctl_space_args *sargs; > >diff --git a/btrfs_cmds.h b/btrfs_cmds.h > >index 7bde191..9cf1ca1 100644 > >--- a/btrfs_cmds.h > >+++ b/btrfs_cmds.h > >@@ -28,7 +28,8 @@ int do_scan(int nargs, char **argv); > > int do_resize(int nargs, char **argv); > > int do_subvol_list(int nargs, char **argv); > > int do_set_default_subvol(int nargs, char **argv); > >-int list_subvols(int fd); > >+int do_get_default_subvol(int nargs, char **argv); > >+int list_subvols(int fd, int get_default); > > int do_df_filesystem(int nargs, char **argv); > > int find_updated_files(int fd, u64 root_id, u64 oldest_gen); > > int do_find_newer(int argc, char **argv); > >-- > >1.7.0.4 > > > >-- > >To unsubscribe from this list: send the line "unsubscribe linux-btrfs" > in > >the body of a message to majordomo@xxxxxxxxxxxxxxx > >More majordomo info at http://vger.kernel.org/majordomo-info.html > ��.n��������+%������w��{.n�����{����n�r������&��z�ޗ�zf���h���~����������_��+v���)ߣ�
