[PATCH 0/3 V2] Btrfs-progs: enhance btrfs subvol list only to show read-only snapshots

[PATCH 0/3 V2] Btrfs-progs: enhance btrfs subvol list only to show read-only snapshots

[zhoubo]

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>

v1->v2: address the comments from Goffredo Baroncelli
- change the changelog of the patches and make them more elaborate.
- move the function declarations to a new head file.
- add the introduction of the new option 'r' into the man page
---
 btrfs-list.c     |   72 +++++++++++++++++++++++++++++++++++++++++++++++------
 btrfs-list.h     |   21 +++++++++++++++
 cmds-inspect.c   |    4 +--
 cmds-subvolume.c |   18 +++++++------
 ctree.h          |    2 +
 man/btrfs.8.in   |    5 ++-
 6 files changed, 100 insertions(+), 22 deletions(-)
 create mode 100644 btrfs-list.h

-- 
1.6.0.6

[PATCH 1/3 V2] Btrfs-progs: move the function declarations to a new head file

[zhoubo]

From: Zhou Bo <zhoub-fnst@cn.fujitsu.com>

Move the function declarations to a new head file.

Signed-off-by: Zhou Bo <zhoub-fnst@cn.fujitsu.com>
---
 btrfs-list.c     |    1 +
 btrfs-list.h     |   21 +++++++++++++++++++++
 cmds-inspect.c   |    4 +---
 cmds-subvolume.c |    5 +----
 4 files changed, 24 insertions(+), 7 deletions(-)
 create mode 100644 btrfs-list.h

diff --git a/btrfs-list.c b/btrfs-list.c
index c53d016..ca841f6 100644
--- a/btrfs-list.c
+++ b/btrfs-list.c
@@ -34,6 +34,7 @@
 #include "ctree.h"
 #include "transaction.h"
 #include "utils.h"
+#include "btrfs-list.h"
 
 /* we store all the roots we find in an rbtree so that we can
  * search for them later.
diff --git a/btrfs-list.h b/btrfs-list.h
new file mode 100644
index 0000000..3cb01f6
--- /dev/null
+++ b/btrfs-list.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2012 Fujitsu.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+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);
+char *path_for_root(int fd, u64 root);
diff --git a/cmds-inspect.c b/cmds-inspect.c
index 2f0228f..f943ed9 100644
--- a/cmds-inspect.c
+++ b/cmds-inspect.c
@@ -24,9 +24,7 @@
 #include "ioctl.h"
 
 #include "commands.h"
-
-/* btrfs-list.c */
-char *path_for_root(int fd, u64 root);
+#include "btrfs-list.h"
 
 static const char * const inspect_cmd_group_usage[] = {
 	"btrfs inspect-internal <command> <args>",
diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index 3508ce6..d8629fa 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -28,10 +28,7 @@
 #include "ioctl.h"
 
 #include "commands.h"
-
-/* btrfs-list.c */
-int list_subvols(int fd, int print_parent, int get_default);
-int find_updated_files(int fd, u64 root_id, u64 oldest_gen);
+#include "btrfs-list.h"
 
 static const char * const subvolume_cmd_group_usage[] = {
 	"btrfs subvolume <command> <args>",
-- 
1.6.0.6

[PATCH 2/3 V2] Btrfs-progs: enhance btrfs subvol list only to show read-only snapshots

[zhoubo]

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

[PATCH 3/3 V2] Btrfs-progs: update the manpage entries for the btrfs subvolume list

[zhoubo]

From: Zhou Bo <zhoub-fnst@cn.fujitsu.com>

This patch adds the introduction of the new option '-r' into the man page of
'btrfs subvolume list' command.

Signed-off-by: Zhou Bo <zhoub-fnst@cn.fujitsu.com>
---
 man/btrfs.8.in |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/man/btrfs.8.in b/man/btrfs.8.in
index 4b0a9f9..0845b4d 100644
--- a/man/btrfs.8.in
+++ b/man/btrfs.8.in
@@ -11,7 +11,7 @@ btrfs \- control a btrfs filesystem
 .PP
 \fBbtrfs\fP \fBsubvolume create\fP\fI [<dest>/]<name>\fP
 .PP
-\fBbtrfs\fP \fBsubvolume list\fP\fI [-p] <path>\fP
+\fBbtrfs\fP \fBsubvolume list\fP\fI [-pr] <path>\fP
 .PP
 \fBbtrfs\fP \fBsubvolume set-default\fP\fI <id> <path>\fP
 .PP
@@ -108,7 +108,7 @@ Create a subvolume in \fI<dest>\fR (or in the current directory if
 \fI<dest>\fR is omitted).
 .TP
 
-\fBsubvolume list\fR\fI [-p] <path>\fR
+\fBsubvolume list\fR\fI [-pr] <path>\fR
 List the subvolumes present in the filesystem \fI<path>\fR. For every
 subvolume the following information is shown by default.
 ID <ID> top level <ID> path <path>
@@ -119,6 +119,7 @@ at mount time via the \fIsubvol=\fR option.
 If \fI-p\fR is given, then \fIparent <ID>\fR is added to the output between ID
 and top level. The parent's ID may be used at mount time via the
 \fIsubvolrootid=\fR option.
+If \fI-r\fR is given, only readonly subvolumes in the filesystem will be listed.
 .TP
 
 \fBsubvolume set-default\fR\fI <id> <path>\fR
-- 
1.6.0.6