zhoubo
2012-Aug-08 08:54 UTC
[PATCH 2/3 V2] Btrfs-progs: enhance btrfs subvol list only to show read-only snapshots
From: Zhou Bo <zhoub-fnst@cn.fujitsu.com>
We want ''btrfs subvolume list'' only to list readonly
subvolumes, this patch set
introduces a new option ''r'' to implement it.
You can use the command like that:
btrfs subvolume list -r <path>
Signed-off-by: Zhou Bo <zhoub-fnst@cn.fujitsu.com>
---
btrfs-list.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++------
cmds-subvolume.c | 13 +++++++---
ctree.h | 2 +
3 files changed, 71 insertions(+), 12 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..90c5c4e 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -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 only list readonly snapshots",
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. The flags
--
1.6.0.6
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html