Add a readonly flag open_ctree to force RO opens

diff --git a/btrfsck.c b/btrfsck.c
index 174c7f9..b447225 100644 (file)
--- a/btrfsck.c
+++ b/btrfsck.c
@@ -746,7 +746,7 @@ int main(int ac, char **av) {
        cache_tree_init(&nodes);
        cache_tree_init(&reada);
 
-       root = open_ctree(av[1], 0);
+       root = open_ctree(av[1], 0, 0);
 
        bits_nr = 1024;
        bits = malloc(bits_nr * sizeof(struct block_info));

diff --git a/convert.c b/convert.c
index 80dc3f5..219f849 100644 (file)
--- a/convert.c
+++ b/convert.c
@@ -2189,7 +2189,7 @@ int do_convert(const char *devname, int datacsum, int packing, int noxattr)
                fprintf(stderr, "unable to update system chunk\n");
                goto fail;
        }
-       root = open_ctree_fd(fd, devname, super_bytenr);
+       root = open_ctree_fd(fd, devname, super_bytenr, O_RDWR);
        if (!root) {
                fprintf(stderr, "unable to open ctree\n");
                goto fail;
@@ -2251,7 +2251,7 @@ int do_convert(const char *devname, int datacsum, int packing, int noxattr)
                goto fail;
        }
 
-       root = open_ctree_fd(fd, devname, 0);
+       root = open_ctree_fd(fd, devname, 0, O_RDWR);
        if (!root) {
                fprintf(stderr, "unable to open ctree\n");
                goto fail;
@@ -2349,7 +2349,7 @@ int do_rollback(const char *devname, int force)
                fprintf(stderr, "unable to open %s\n", devname);
                goto fail;
        }
-       root = open_ctree_fd(fd, devname, 0);
+       root = open_ctree_fd(fd, devname, 0, O_RDWR);
        if (!root) {
                fprintf(stderr, "unable to open ctree\n");
                goto fail;

diff --git a/ctree.h b/ctree.h
index d285344..a5a284c 100644 (file)
--- a/ctree.h
+++ b/ctree.h
@@ -515,6 +515,7 @@ struct btrfs_fs_info {
        struct btrfs_fs_devices *fs_devices;
        struct list_head space_info;
        int system_allocs;
+       int readonly;
 };
 
 /*

diff --git a/debug-tree.c b/debug-tree.c
index acfa442..21162ec 100644 (file)
--- a/debug-tree.c
+++ b/debug-tree.c
@@ -130,7 +130,7 @@ int main(int ac, char **av)
        if (ac != 1)
                print_usage();
 
-       root = open_ctree(av[optind], 0);
+       root = open_ctree(av[optind], 0, 0);
        if (!root) {
                fprintf(stderr, "unable to open %s\n", av[optind]);
                exit(1);

diff --git a/dir-test.c b/dir-test.c
index 54ddee2..44f2758 100644 (file)
--- a/dir-test.c
+++ b/dir-test.c
@@ -435,7 +435,7 @@ int main(int ac, char **av)
        struct btrfs_trans_handle *trans;
        radix_tree_init();
 
-       root = open_ctree(av[ac-1], &super);
+       root = open_ctree(av[ac-1], &super, 0);
        trans = btrfs_start_transaction(root, 1);
 
        dir_oid = btrfs_super_root_dir(&super);
@@ -478,7 +478,7 @@ int main(int ac, char **av)
                                btrfs_header_level(&root->node->node.header),
                                btrfs_header_nritems(&root->node->node.header));
                        close_ctree(root, &super);
-                       root = open_ctree("dbfile", &super);
+                       root = open_ctree("dbfile", &super, 0);
                }
                while(count--) {
                        ret = ops[op](trans, root, &radix);

diff --git a/disk-io.c b/disk-io.c
index 23c9aa8..939f772 100644 (file)
--- a/disk-io.c
+++ b/disk-io.c
@@ -454,22 +454,27 @@ insert:
        return root;
 }
 
-struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr)
+struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes)
 {
        int fp;
        struct btrfs_root *root;
+       int flags = O_CREAT | O_RDWR;
 
-       fp = open(filename, O_CREAT | O_RDWR, 0600);
+       if (!writes)
+               flags = O_RDONLY;
+
+       fp = open(filename, flags, 0600);
        if (fp < 0) {
                return NULL;
        }
-       root = open_ctree_fd(fp, filename, sb_bytenr);
+       root = open_ctree_fd(fp, filename, sb_bytenr, writes);
        close(fp);
 
        return root;
 }
 
-struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr)
+struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
+                                int writes)
 {
        u32 sectorsize;
        u32 nodesize;
@@ -510,6 +515,9 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr)
        fs_info->chunk_root = chunk_root;
        fs_info->dev_root = dev_root;
 
+       if (!writes)
+               fs_info->readonly = 1;
+
        extent_io_tree_init(&fs_info->extent_cache);
        extent_io_tree_init(&fs_info->free_space_cache);
        extent_io_tree_init(&fs_info->block_group_cache);
@@ -527,7 +535,10 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr)
        __setup_root(4096, 4096, 4096, 4096, tree_root,
                     fs_info, BTRFS_ROOT_TREE_OBJECTID);
 
-       ret = btrfs_open_devices(fs_devices, O_RDWR);
+       if (writes)
+               ret = btrfs_open_devices(fs_devices, O_RDWR);
+       else
+               ret = btrfs_open_devices(fs_devices, O_RDONLY);
        BUG_ON(ret);
 
        ret = btrfs_bootstrap_super_map(&fs_info->mapping_tree, fs_devices);
@@ -656,6 +667,10 @@ int write_ctree_super(struct btrfs_trans_handle *trans,
        int ret;
        struct btrfs_root *tree_root = root->fs_info->tree_root;
        struct btrfs_root *chunk_root = root->fs_info->chunk_root;
+
+       if (root->fs_info->readonly)
+               return 0;
+
        btrfs_set_super_generation(&root->fs_info->super_copy,
                                   trans->transid);
        btrfs_set_super_root(&root->fs_info->super_copy,

diff --git a/disk-io.h b/disk-io.h
index bd8ca63..b032844 100644 (file)
--- a/disk-io.h
+++ b/disk-io.h
@@ -31,8 +31,9 @@ struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
                                                   u64 bytenr, u32 blocksize);
 int clean_tree_block(struct btrfs_trans_handle *trans,
                     struct btrfs_root *root, struct extent_buffer *buf);
-struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr);
-struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr);
+struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes);
+struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
+                                int writes);
 int close_ctree(struct btrfs_root *root);
 int write_ctree_super(struct btrfs_trans_handle *trans,
                      struct btrfs_root *root);

diff --git a/mkfs.c b/mkfs.c
index 740cc81..e1b4297 100644 (file)
--- a/mkfs.c
+++ b/mkfs.c
@@ -77,7 +77,7 @@ static int make_root_dir(int fd, const char *device_name) {
        u64 chunk_size = 0;
        int ret;
 
-       root = open_ctree_fd(fd, device_name, 0);
+       root = open_ctree_fd(fd, device_name, 0, O_RDWR);
 
        if (!root) {
                fprintf(stderr, "ctree init failed\n");
@@ -408,7 +408,7 @@ int main(int ac, char **av)
                fprintf(stderr, "failed to setup the root directory\n");
                exit(1);
        }
-       root = open_ctree(file, 0);
+       root = open_ctree(file, 0, O_RDWR);
        root->fs_info->alloc_start = alloc_start;
        trans = btrfs_start_transaction(root, 1);
 

diff --git a/quick-test.c b/quick-test.c
index 16a3bf4..44c2318 100644 (file)
--- a/quick-test.c
+++ b/quick-test.c
@@ -50,7 +50,7 @@ int main(int ac, char **av) {
 
        radix_tree_init();
 
-       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET);
+       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET, O_RDWR);
        trans = btrfs_start_transaction(root, 1);
        srand(55);
        btrfs_set_key_type(&ins, BTRFS_STRING_ITEM_KEY);
@@ -73,7 +73,7 @@ int main(int ac, char **av) {
        btrfs_commit_transaction(trans, root);
        close_ctree(root);
        exit(1);
-       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET);
+       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET, O_RDWR);
        printf("starting search\n");
        srand(55);
        for (i = 0; i < run_size; i++) {
@@ -92,7 +92,7 @@ int main(int ac, char **av) {
        }
        close_ctree(root);
 
-       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET);
+       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET, O_RDWR);
        printf("node %p level %d total ptrs %d free spc %lu\n", root->node,
                btrfs_header_level(root->node),
                btrfs_header_nritems(root->node),
@@ -120,7 +120,7 @@ int main(int ac, char **av) {
        btrfs_commit_transaction(trans, root);
        close_ctree(root);
 
-       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET);
+       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET, O_RDWR);
        trans = btrfs_start_transaction(root, 1);
        srand(128);
        for (i = 0; i < run_size; i++) {
@@ -136,7 +136,7 @@ int main(int ac, char **av) {
        btrfs_commit_transaction(trans, root);
        close_ctree(root);
 
-       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET);
+       root = open_ctree(av[1], BTRFS_SUPER_INFO_OFFSET, O_RDWR);
        srand(128);
        printf("starting search2\n");
        for (i = 0; i < run_size; i++) {