From a70b0b2bba94fe62541cc21a9afe35015521fcc3 Mon Sep 17 00:00:00 2001 From: "Zhong, Xin" Date: Tue, 12 Jul 2011 10:48:37 +0800 Subject: Btrfs-progs: add "btrfs subvolume get-default" subcommand Add subcommand to get the default subvolume of btrfs filesystem V2->V3: * add man page * based on http://git.darksatanic.net/repo/btrfs-progs-unstable.git integration-20110705 Reviewed-by: Andreas Philipp Reviewed-by: Goffredo Baroncelli Reported-by: Yang, Yi Signed-off-by: Zhong, Xin --- btrfs-list.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- btrfs.c | 3 +++ btrfs_cmds.c | 31 ++++++++++++++++++++++++++++++- btrfs_cmds.h | 3 ++- man/btrfs.8.in | 7 +++++++ 5 files changed, 98 insertions(+), 4 deletions(-) diff --git a/btrfs-list.c b/btrfs-list.c index ab73e65..817a450 100644 --- a/btrfs-list.c +++ b/btrfs-list.c @@ -560,7 +560,7 @@ build: return full; } -int list_subvols(int fd, int print_parent) +int list_subvols(int fd, int print_parent, int get_default) { struct root_lookup root_lookup; struct rb_node *n; @@ -569,10 +569,12 @@ int list_subvols(int fd, int print_parent) struct btrfs_ioctl_search_key *sk = &args.key; struct btrfs_ioctl_search_header *sh; struct btrfs_root_ref *ref; + struct btrfs_dir_item *di; unsigned long off = 0; int name_len; char *name; u64 dir_id; + u64 subvol_id = 0; int i; int e; @@ -669,6 +671,52 @@ int list_subvols(int fd, int print_parent) n = rb_next(n); } + memset(&args, 0, sizeof(args)); + + /* search in the tree of tree roots */ + sk->tree_id = BTRFS_ROOT_TREE_OBJECTID; + + /* 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; + + /* just a big number, doesn't matter much */ + sk->nr_items = 4096; + + /* try to get the objectid of default subvolume */ + if (get_default) { + ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args); + if (ret < 0) { + fprintf(stderr, "ERROR: can't perform the search\n"); + return ret; + } + + off = 0; + /* 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; + } + } + /* 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 @@ -677,7 +725,13 @@ int list_subvols(int fd, int print_parent) while (n) { struct root_info *entry; entry = rb_entry(n, struct root_info, rb_node); - resolve_root(&root_lookup, entry, print_parent); + if (!get_default) + resolve_root(&root_lookup, entry, print_parent); + /* we only want the default subvolume */ + else if (subvol_id == entry->root_id) + resolve_root(&root_lookup, entry, print_parent); + else if (subvol_id == 0) + break; n = rb_prev(n); } diff --git a/btrfs.c b/btrfs.c index a3f9a01..a48f07b 100644 --- a/btrfs.c +++ b/btrfs.c @@ -94,6 +94,9 @@ static struct Command commands[] = { "-l len defragment only up to len bytes\n" "-t size minimal size of file to be considered for defragmenting\n" }, + { do_get_default_subvol, 1, "subvolume get-default", "\n" + "Get the default subvolume of a filesystem." + }, { do_fssync, 1, "filesystem sync", "\n" "Force a sync on the filesystem .", diff --git a/btrfs_cmds.c b/btrfs_cmds.c index 699dfc2..7d2fd8c 100644 --- a/btrfs_cmds.c +++ b/btrfs_cmds.c @@ -339,7 +339,7 @@ int do_subvol_list(int argc, char **argv) fprintf(stderr, "ERROR: can't access '%s'\n", subvol); return 12; } - ret = list_subvols(fd, print_parent); + ret = list_subvols(fd, print_parent, 0); if (ret) return 19; return 0; @@ -953,6 +953,35 @@ int do_change_label(int nargs, char **argv) } +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, 0, 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 3e171da..8958596 100644 --- a/btrfs_cmds.h +++ b/btrfs_cmds.h @@ -32,7 +32,8 @@ 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 print_parent); +int do_get_default_subvol(int nargs, char **argv); +int list_subvols(int fd, int print_parent, 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); diff --git a/man/btrfs.8.in b/man/btrfs.8.in index faa7bf8..e830abd 100644 --- a/man/btrfs.8.in +++ b/man/btrfs.8.in @@ -15,6 +15,8 @@ btrfs \- control a btrfs filesystem .PP \fBbtrfs\fP \fBsubvolume set-default\fP\fI \fP .PP +\fBbtrfs\fP \fBsubvolume get-default\fP\fI \fP +.PP \fBbtrfs\fP \fBfilesystem sync\fP\fI \fP .PP \fBbtrfs\fP \fBfilesystem resize\fP\fI [+/\-][gkm]|max \fP @@ -120,6 +122,11 @@ Set the subvolume of the filesystem \fI\fR which is mounted as is returned by the \fBsubvolume list\fR command. .TP +\fBsubvolume get-default\fR\fI \fR +Get the default subvolume of the filesystem \fI\fR. The output format +is similar to \fBsubvolume list\fR command. +.TP + \fBfilesystem defragment\fP -c[zlib|lzo] [-l \fIlen\fR] [-s \fIstart\fR] [-t \fIsize\fR] -[vf] <\fIfile\fR>|<\fIdir\fR> [<\fIfile\fR>|<\fIdir\fR>...] Defragment file data and/or directory metadata. To defragment all files in a -- cgit v1.2.1