[Btrfs-devel][PATCH]Add rollback support for the converter
Yan Zheng
yanzheng at 21cn.com
Mon Jan 7 08:06:43 PST 2008
Hello,
This patch adds rollback support for the converter, the converter can
roll back a conversion if the image file haven't been modified. In
addition, I rearrange some codes in convert.c and add a few comments.
Regards
YZ
---
diff -r 12138d4beeb0 convert.c
--- a/convert.c Fri Jan 04 11:29:55 2008 -0500
+++ b/convert.c Mon Jan 07 23:35:25 2008 +0800
@@ -33,6 +33,7 @@
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
+#include "crc32c.h"
#include "utils.h"
#include "ext2fs/ext2_fs.h"
#include "ext2fs/ext2fs.h"
@@ -43,7 +44,7 @@
* Open Ext2fs in readonly mode, read block allocation bitmap and
* inode bitmap into memory.
*/
-static int open_ext2fs(char *name, ext2_filsys *ret_fs)
+static int open_ext2fs(const char *name, ext2_filsys *ret_fs)
{
int mnt_flags;
errcode_t ret;
@@ -88,9 +89,6 @@ static int close_ext2fs(ext2_filsys fs)
return 0;
}
-/*
- * Stupid algorithm, search forward starting from the first free block.
- */
static int ext2_alloc_block(ext2_filsys fs, u64 goal, u64 *block_ret)
{
blk_t block;
@@ -115,6 +113,7 @@ static int custom_alloc_extent(struct bt
{
ext2_filsys fs = (ext2_filsys)root->fs_info->priv_data;
u32 blocksize = fs->blocksize;
+ u64 first = 0;
u64 block;
u64 bytenr;
int ret;
@@ -127,6 +126,12 @@ static int custom_alloc_extent(struct bt
if (ret)
return ret;
+ /* all free blocks are pinned */
+ if (first == block)
+ return -ENOSPC;
+ if (first == 0)
+ first = block;
+
bytenr = block * blocksize;
if (!test_range_bit(&root->fs_info->pinned_extents, bytenr,
bytenr + blocksize - 1, EXTENT_DIRTY, 0))
@@ -167,7 +172,7 @@ struct dir_iterate_data {
struct btrfs_root *root;
struct btrfs_inode_item *inode;
u64 objectid;
- u32 parent;
+ u64 parent;
int errcode;
};
@@ -281,10 +286,9 @@ fail:
}
/*
- * record a single file extent. do all required works:
- * 1. insert a btrfs_file_extent_item into fs tree.
- * 2. compute checksum and insert btrfs_csum_item into fs tree.
- * 3. insert extent item and extent backref into extent tree.
+ * Record a file extent. Do all the required works, such as inserting
+ * file extent item, inserting extent item and backref item into extent
+ * tree and updating block accounting.
*/
static int record_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid,
@@ -446,8 +450,7 @@ static int create_file_extents(struct bt
static int create_file_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid,
struct btrfs_inode_item *btrfs_inode,
- ext2_filsys ext2_fs, ext2_ino_t ext2_ino,
- struct ext2_inode *ext2_inode)
+ ext2_filsys ext2_fs, ext2_ino_t ext2_ino)
{
int ret;
char *buffer = NULL;
@@ -455,6 +458,7 @@ static int create_file_extents(struct bt
u32 last_block;
u32 sectorsize = root->sectorsize;
u64 inode_size = btrfs_stack_inode_size(btrfs_inode);
+ u32 inode_flags = btrfs_stack_inode_flags(btrfs_inode);
struct blk_iterate_data data = {
.trans = trans,
.root = root,
@@ -466,6 +470,9 @@ static int create_file_extents(struct bt
.checksum = 1,
.errcode = 0,
};
+
+ if (inode_flags & BTRFS_INODE_NODATASUM)
+ data.checksum = 0;
err = ext2fs_block_iterate2(ext2_fs, ext2_ino, BLOCK_FLAG_DATA_ONLY,
NULL, __block_iterate_proc, &data);
@@ -495,7 +502,7 @@ static int create_file_extents(struct bt
} else if (data.num_blocks > 0) {
ret = record_file_blocks(trans, root, objectid, btrfs_inode,
data.first_block, data.disk_block,
- data.num_blocks, 1);
+ data.num_blocks, data.checksum);
if (ret)
goto fail;
}
@@ -504,7 +511,7 @@ static int create_file_extents(struct bt
if (last_block > data.first_block) {
ret = record_file_blocks(trans, root, objectid, btrfs_inode,
data.first_block, 0, last_block -
- data.first_block, 1);
+ data.first_block, data.checksum);
}
fail:
if (buffer)
@@ -527,8 +534,8 @@ static int create_symbol_link(struct btr
if (ext2fs_inode_data_blocks(ext2_fs, ext2_inode)) {
btrfs_set_stack_inode_size(btrfs_inode, inode_size + 1);
- ret = create_file_extents(trans, root, objectid, btrfs_inode,
- ext2_fs, ext2_ino, ext2_inode);
+ ret = create_file_extents(trans, root, objectid,
+ btrfs_inode, ext2_fs, ext2_ino);
btrfs_set_stack_inode_size(btrfs_inode, inode_size);
return ret;
}
@@ -558,7 +565,7 @@ static int copy_inode_item(struct btrfs_
static int copy_inode_item(struct btrfs_inode_item *dst,
struct ext2_inode *src)
{
- btrfs_set_stack_inode_generation(dst, 0);
+ btrfs_set_stack_inode_generation(dst, 1);
btrfs_set_stack_inode_size(dst, src->i_size);
btrfs_set_stack_inode_nblocks(dst, src->i_blocks);
btrfs_set_stack_inode_block_group(dst, 0);
@@ -602,7 +609,8 @@ static int copy_inode_item(struct btrfs_
*/
static int copy_single_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid,
- ext2_filsys ext2_fs, ext2_ino_t ext2_ino)
+ ext2_filsys ext2_fs, ext2_ino_t ext2_ino,
+ int datacsum)
{
int ret;
errcode_t err;
@@ -621,20 +629,24 @@ static int copy_single_inode(struct btrf
}
copy_inode_item(&btrfs_inode, &ext2_inode);
-
- ret = 0;
+ if (!datacsum && S_ISREG(ext2_inode.i_mode)) {
+ u32 flags = btrfs_stack_inode_flags(&btrfs_inode) |
+ BTRFS_INODE_NODATASUM;
+ btrfs_set_stack_inode_flags(&btrfs_inode, flags);
+ }
+
switch (ext2_inode.i_mode & S_IFMT) {
case S_IFREG:
ret = create_file_extents(trans, root, objectid, &btrfs_inode,
- ext2_fs, ext2_ino, &ext2_inode);
+ ext2_fs, ext2_ino);
+ break;
+ case S_IFDIR:
+ ret = create_dir_entries(trans, root, objectid, &btrfs_inode,
+ ext2_fs, ext2_ino);
break;
case S_IFLNK:
ret = create_symbol_link(trans, root, objectid, &btrfs_inode,
ext2_fs, ext2_ino, &ext2_inode);
- break;
- case S_IFDIR:
- ret = create_dir_entries(trans, root, objectid,
- &btrfs_inode, ext2_fs, ext2_ino);
break;
default:
ret = 0;
@@ -679,7 +691,8 @@ fail:
/*
* scan ext2's inode bitmap and copy all used inode.
*/
-static int copy_inodes(struct btrfs_root *root, ext2_filsys ext2_fs)
+static int copy_inodes(struct btrfs_root *root, ext2_filsys ext2_fs,
+ int datacsum)
{
int ret;
ext2_ino_t ext2_ino;
@@ -699,7 +712,7 @@ static int copy_inodes(struct btrfs_root
continue;
objectid = ext2_ino + INO_OFFSET;
ret = copy_single_inode(trans, root, objectid,
- ext2_fs, ext2_ino);
+ ext2_fs, ext2_ino, datacsum);
if (ret)
return ret;
}
@@ -716,7 +729,7 @@ static int copy_inodes(struct btrfs_root
return ret;
}
-static int lookup_extent_ref(struct btrfs_trans_handle *trans,
+static int lookup_extent_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 bytenr, u64 num_bytes)
{
@@ -726,8 +739,8 @@ static int lookup_extent_ref(struct btrf
btrfs_init_path(&path);
key.objectid = bytenr;
- key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
+ btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
ret = btrfs_search_slot(trans, root->fs_info->extent_root,
&key, &path, 0, 0);
btrfs_release_path(root, &path);
@@ -738,6 +751,9 @@ static int lookup_extent_ref(struct btrf
* Construct a range of ext2fs image file.
* scan block allocation bitmap, find all blocks used by the ext2fs
* in this range and create file extents that point to these blocks.
+ *
+ * Note: Before calling the function, no file extent points to blocks
+ * in this range
*/
static int create_image_file_range(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid,
@@ -758,7 +774,7 @@ static int create_image_file_range(struc
.first_block = block,
.disk_block = block,
.num_blocks = 0,
- .checksum = 1,
+ .checksum = 0,
.errcode = 0,
};
@@ -767,7 +783,7 @@ static int create_image_file_range(struc
continue;
/* the bit may be set by us, check extent tree */
bytenr = (u64)block * blocksize;
- ret = lookup_extent_ref(trans, root, bytenr, blocksize);
+ ret = lookup_extent_item(trans, root, bytenr, blocksize);
if (ret < 0)
goto fail;
if (ret == 0)
@@ -783,7 +799,7 @@ static int create_image_file_range(struc
if (data.num_blocks > 0) {
ret = record_file_blocks(trans, root, objectid, inode,
data.first_block, data.disk_block,
- data.num_blocks, 1);
+ data.num_blocks, 0);
if (ret)
return ret;
data.first_block += data.num_blocks;
@@ -791,7 +807,7 @@ static int create_image_file_range(struc
if (last_block > data.first_block) {
ret = record_file_blocks(trans, root, objectid, inode,
data.first_block, 0, last_block -
- data.first_block, 1);
+ data.first_block, 0);
if (ret)
return ret;
}
@@ -802,8 +818,8 @@ fail:
/*
* Create the ext2fs image file.
*/
-static int create_ext2_image(struct btrfs_root *root, char *name,
- int namelen, ext2_filsys ext2_fs)
+static int create_ext2_image(struct btrfs_root *root, ext2_filsys ext2_fs,
+ const char *name)
{
int ret;
struct btrfs_key key;
@@ -837,7 +853,8 @@ static int create_ext2_image(struct btrf
btrfs_set_stack_inode_size(&btrfs_inode, total_bytes);
btrfs_set_stack_inode_nlink(&btrfs_inode, 1);
btrfs_set_stack_inode_nblocks(&btrfs_inode, 0);
- btrfs_set_stack_inode_mode(&btrfs_inode, S_IFREG | 0444);
+ btrfs_set_stack_inode_mode(&btrfs_inode, S_IFREG | 0400);
+ btrfs_set_stack_inode_flags(&btrfs_inode, BTRFS_INODE_NODATASUM);
btrfs_init_path(&path);
trans = btrfs_start_transaction(root, 1);
@@ -862,7 +879,7 @@ static int create_ext2_image(struct btrf
goto fail;
ret = record_file_extent(trans, root, objectid,
&btrfs_inode, last_byte,
- new_block, sectorsize, 1);
+ new_block, sectorsize, 0);
if (ret)
goto fail;
}
@@ -902,6 +919,11 @@ again:
continue;
}
+ /*
+ * Check backref to distinguish extent items for normal
+ * files (files that correspond to files in Ext2fs) from
+ * extent items for ctree blocks.
+ */
bytenr = key.objectid;
num_bytes = key.offset;
file_extent = 0;
@@ -944,7 +966,7 @@ again:
goto fail;
}
ret = record_file_extent(trans, root, objectid, &btrfs_inode,
- bytenr, bytenr, num_bytes, 1);
+ bytenr, bytenr, num_bytes, 0);
if (ret)
goto fail;
last_byte = bytenr + num_bytes;
@@ -958,6 +980,14 @@ again:
goto fail;
}
+ /*
+ * otime isn't used currently, so we can store some data in it.
+ * These data are used by do_rollback to check whether the image
+ * file have been modified.
+ */
+ btrfs_set_stack_timespec_sec(&btrfs_inode.otime, trans->transid);
+ btrfs_set_stack_timespec_nsec(&btrfs_inode.otime,
+ total_bytes / sectorsize);
ret = btrfs_insert_inode(trans, root, objectid, &btrfs_inode);
if (ret)
goto fail;
@@ -965,12 +995,13 @@ again:
location.objectid = objectid;
location.offset = 0;
btrfs_set_key_type(&location, BTRFS_INODE_ITEM_KEY);
- ret = btrfs_insert_dir_item(trans, root, name, namelen,
+ ret = btrfs_insert_dir_item(trans, root, name, strlen(name),
btrfs_root_dirid(&root->root_item),
&location, EXT2_FT_REG_FILE);
if (ret)
goto fail;
- ret = btrfs_insert_inode_ref(trans, root, name, namelen, objectid,
+ ret = btrfs_insert_inode_ref(trans, root, name, strlen(name),
+ objectid,
btrfs_root_dirid(&root->root_item));
if (ret)
goto fail;
@@ -981,8 +1012,7 @@ fail:
return ret;
}
-struct btrfs_root *create_subvol(struct btrfs_root *root,
- char *name, int namelen)
+struct btrfs_root *create_subvol(struct btrfs_root *root, const char *name)
{
int ret;
u64 objectid;
@@ -1017,12 +1047,13 @@ struct btrfs_root *create_subvol(struct
if (ret)
goto fail;
location.offset = (u64)-1;
- ret = btrfs_insert_dir_item(trans, tree_root, name, namelen,
+ ret = btrfs_insert_dir_item(trans, tree_root, name, strlen(name),
btrfs_super_root_dir(&fs_info->super_copy),
&location, BTRFS_FT_DIR);
if (ret)
goto fail;
- ret = btrfs_insert_inode_ref(trans, tree_root, name, namelen, objectid,
+ ret = btrfs_insert_inode_ref(trans, tree_root, name, strlen(name),
+ objectid,
btrfs_super_root_dir(&fs_info->super_copy));
if (ret)
goto fail;
@@ -1030,9 +1061,8 @@ struct btrfs_root *create_subvol(struct
BUG_ON(ret);
new_root = btrfs_read_fs_root(fs_info, &location);
- if (!new_root) {
- return NULL;
- }
+ if (!new_root || IS_ERR(new_root))
+ goto fail;
trans = btrfs_start_transaction(new_root, 1);
BUG_ON(!trans);
@@ -1145,38 +1175,69 @@ err:
}
/*
- * Migrate super block to it's default position.
- * This function is dangerous, it modifies a block used by ext2fs.
+ * Migrate super block to it's default position and zero 0 ~ 16k
*/
-static int migrate_super_block(struct btrfs_root *root, u64 sb_offset)
-{
- int ret = -1;
- struct extent_buffer *old_eb;
- struct extent_buffer *sb_buffer;
- struct btrfs_trans_handle *trans;
-
- BUG_ON(sb_offset != BTRFS_SUPER_INFO_OFFSET);
- sb_buffer = read_tree_block(root, sb_offset, 512);
- if (!sb_buffer)
- goto fail;
- memset_extent_buffer(sb_buffer, 0, 0, sb_buffer->len);
- old_eb = root->fs_info->sb_buffer;
- root->fs_info->sb_buffer = sb_buffer;
- btrfs_set_super_bytenr(&root->fs_info->super_copy, sb_offset);
- trans = btrfs_start_transaction(root, 1);
- BUG_ON(!trans);
- ret = btrfs_free_extent(trans, root, old_eb->start, root->leafsize,
- 0, 0, 0, 0, 1);
- if (ret)
- goto fail;
- ret = btrfs_commit_transaction(trans, root);
- free_extent_buffer(old_eb);
- BUG_ON(ret);
+static int migrate_super_block(int fd, u64 old_bytenr, u32 sectorsize)
+{
+ int ret;
+ char *buf;
+ u64 bytenr;
+ u32 crc = ~(u32)0;
+ u32 len = 512 - BTRFS_CSUM_SIZE;
+ struct btrfs_super_block *super;
+
+ ret = fsync(fd);
+ if (ret)
+ goto fail;
+
+ BUG_ON(sectorsize < sizeof(super));
+ buf = malloc(sectorsize);
+ if (!buf)
+ return -ENOMEM;
+ ret = pread(fd, buf, sectorsize, old_bytenr);
+ if (ret != sectorsize)
+ goto fail;
+
+ super = (struct btrfs_super_block *)buf;
+ BUG_ON(btrfs_super_bytenr(super) != old_bytenr);
+ btrfs_set_super_bytenr(super, BTRFS_SUPER_INFO_OFFSET);
+
+ crc = crc32c(crc, buf + BTRFS_CSUM_SIZE, len);
+ crc = ~cpu_to_le32(crc);
+ memcpy(super->csum, &crc, BTRFS_CRC32_SIZE);
+
+ ret = pwrite(fd, buf, sectorsize, BTRFS_SUPER_INFO_OFFSET);
+ if (ret < 0)
+ goto fail;
+ /* How to handle this case? */
+ BUG_ON(ret != sectorsize);
+
+ ret = fsync(fd);
+ if (ret)
+ goto fail;
+
+ memset(buf, 0, sectorsize);
+ for (bytenr = 0; bytenr < BTRFS_SUPER_INFO_OFFSET; ) {
+ len = BTRFS_SUPER_INFO_OFFSET - bytenr;
+ if (len > sectorsize)
+ len = sectorsize;
+ ret = pwrite(fd, buf, len, bytenr);
+ if (ret != len) {
+ fprintf(stderr, "unable to zero fill device\n");
+ break;
+ }
+ bytenr += len;
+ }
+ ret = 0;
+ fsync(fd);
fail:
+ free(buf);
+ if (ret > 0)
+ ret = -1;
return ret;
}
-int main(int argc, char *argv[])
+int do_convert(const char *devname, int datacsum)
{
int i, fd, ret;
u32 blocksize;
@@ -1185,15 +1246,11 @@ int main(int argc, char *argv[])
u64 super_bytenr;
ext2_filsys ext2_fs;
struct btrfs_root *root;
- struct btrfs_root *snap_root;
-
- if (argc != 2) {
- fprintf(stderr, "usage: %s device\n", argv[0]);
- exit(1);
- }
- ret = open_ext2fs(argv[1], &ext2_fs);
+ struct btrfs_root *ext2_root;
+
+ ret = open_ext2fs(devname, &ext2_fs);
if (ret) {
- fprintf(stderr, "failed to open the Ext2fs\n");
+ fprintf(stderr, "unable to open the Ext2fs\n");
goto fail;
}
blocksize = ext2_fs->blocksize;
@@ -1204,7 +1261,7 @@ int main(int argc, char *argv[])
}
if (!(ext2_fs->super->s_feature_incompat &
EXT2_FEATURE_INCOMPAT_FILETYPE)) {
- fprintf(stderr, "missing filetype feature\n");
+ fprintf(stderr, "filetype feature is missing\n");
goto fail;
}
for (i = 0; i < 4; i++) {
@@ -1217,63 +1274,309 @@ int main(int argc, char *argv[])
}
super_bytenr = blocks[0];
- fd = open(argv[1], O_RDWR);
+ fd = open(devname, O_RDWR);
if (fd < 0) {
- fprintf(stderr, "unable to open %s\n", argv[1]);
+ fprintf(stderr, "unable to open %s\n", devname);
goto fail;
}
ret = make_btrfs(fd, blocks, total_bytes, blocksize,
blocksize, blocksize, blocksize);
if (ret) {
- fprintf(stderr, "failed to create ctree\n");
+ fprintf(stderr, "unable to create initial ctree\n");
goto fail;
}
root = open_ctree_fd(fd, super_bytenr);
if (!root) {
- fprintf(stderr, "failed to open ctree\n");
- goto fail;
- }
-
+ fprintf(stderr, "unable to open ctree\n");
+ goto fail;
+ }
+ fd = dup(fd);
+ if (fd < 0) {
+ fprintf(stderr, "unable to duplicate file descriptor\n");
+ goto fail;
+ }
root->fs_info->priv_data = ext2_fs;
root->fs_info->extent_ops = &extent_ops;
ret = init_btrfs(root);
if (ret) {
- fprintf(stderr, "failed to setup the root tree\n");
- goto fail;
- }
- snap_root = create_subvol(root, "ext2_saved", 10);
- if (!snap_root) {
- fprintf(stderr, "failed to create subvol\n");
+ fprintf(stderr, "unable to setup the root tree\n");
+ goto fail;
+ }
+ ext2_root = create_subvol(root, "ext2_saved");
+ if (!ext2_root) {
+ fprintf(stderr, "unable to create subvol\n");
goto fail;
}
printf("creating btrfs metadata.\n");
- ret = copy_inodes(root, ext2_fs);
+ ret = copy_inodes(root, ext2_fs, datacsum);
if (ret) {
fprintf(stderr, "error during copy_inodes %d\n", ret);
goto fail;
}
printf("creating ext2fs image file.\n");
- ret = create_ext2_image(snap_root, "image", 5, ext2_fs);
+ ret = create_ext2_image(ext2_root, ext2_fs, "image");
if (ret) {
- fprintf(stderr, "failed to create fs image\n");
- goto fail;
- }
- ret = migrate_super_block(root, BTRFS_SUPER_INFO_OFFSET);
- if (ret) {
- fprintf(stderr, "failed to update super block\n");
- goto fail;
- }
- btrfs_free_fs_root(snap_root->fs_info, snap_root);
+ fprintf(stderr, "error during create_ext2_image %d\n", ret);
+ goto fail;
+ }
+ btrfs_free_fs_root(ext2_root->fs_info, ext2_root);
ret = close_ctree(root);
if (ret) {
fprintf(stderr, "error during close_ctree %d\n", ret);
goto fail;
}
close_ext2fs(ext2_fs);
+
+ /* finally migrate super block to its default postion */
+ ret = migrate_super_block(fd, super_bytenr, blocksize);
+ if (ret) {
+ fprintf(stderr, "unable to migrate super block\n");
+ goto fail;
+ }
+ close(fd);
printf("conversion complete.\n");
- exit(0);
+ return 0;
fail:
- fprintf(stderr, "conversion abort.\n");
+ fprintf(stderr, "conversion aborted.\n");
+ return -1;
+}
+
+int do_rollback(const char *devname, int force)
+{
+ int fd;
+ int ret;
+ int modified = 0;
+ struct btrfs_root *root;
+ struct btrfs_root *ext2_root;
+ struct btrfs_dir_item *dir;
+ struct btrfs_inode_item *inode;
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_inode_timespec *tspec;
+ struct extent_buffer *leaf;
+ struct btrfs_key key;
+ struct btrfs_path path;
+ char *buf;
+ char *name;
+ u64 bytenr;
+ u64 num_bytes;
+ u64 root_dir;
+ u64 objectid;
+ u64 offset;
+ u64 first_free;
+ u64 last_trans;
+ u64 total_bytes;
+
+ fd = open(devname, O_RDWR);
+ if (fd < 0) {
+ fprintf(stderr, "unable to open %s\n", devname);
+ goto fail;
+ }
+ root = open_ctree_fd(fd, 0);
+ if (!root) {
+ fprintf(stderr, "unable to open ctree\n");
+ goto fail;
+ }
+ fd = dup(fd);
+ if (fd < 0) {
+ fprintf(stderr, "unable to duplicate file descriptor\n");
+ goto fail;
+ }
+
+ first_free = BTRFS_SUPER_INFO_OFFSET + root->sectorsize * 2 - 1;
+ first_free &= ~((u64)root->sectorsize - 1);
+ buf = malloc(first_free);
+ if (!buf) {
+ fprintf(stderr, "unable to allocate memory\n");
+ goto fail;
+ }
+
+ btrfs_init_path(&path);
+ name = "ext2_saved";
+ root_dir = btrfs_super_root_dir(&root->fs_info->super_copy);
+ dir = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root, &path,
+ root_dir, name, strlen(name), 0);
+ if (!dir || IS_ERR(dir)) {
+ fprintf(stderr, "unable to find subvol %s\n", name);
+ goto fail;
+ }
+ leaf = path.nodes[0];
+ btrfs_dir_item_key_to_cpu(leaf, dir, &key);
+ btrfs_release_path(root->fs_info->tree_root, &path);
+
+ ext2_root = btrfs_read_fs_root(root->fs_info, &key);
+ if (!ext2_root || IS_ERR(ext2_root)) {
+ fprintf(stderr, "unable to open subvol %s\n", name);
+ goto fail;
+ }
+
+ name = "image";
+ root_dir = btrfs_root_dirid(&root->root_item);
+ dir = btrfs_lookup_dir_item(NULL, ext2_root, &path,
+ root_dir, name, strlen(name), 0);
+ if (!dir || IS_ERR(dir)) {
+ fprintf(stderr, "unable to find file %s\n", name);
+ goto fail;
+ }
+ leaf = path.nodes[0];
+ btrfs_dir_item_key_to_cpu(leaf, dir, &key);
+ btrfs_release_path(ext2_root, &path);
+
+ objectid = key.objectid;
+
+ ret = btrfs_lookup_inode(NULL, ext2_root, &path, &key, 0);
+ if (ret) {
+ fprintf(stderr, "unable to find inode item\n");
+ goto fail;
+ }
+ leaf = path.nodes[0];
+ inode = btrfs_item_ptr(leaf, path.slots[0], struct btrfs_inode_item);
+ tspec = btrfs_inode_otime(inode);
+ /*
+ * get image file size and transaction id stored in 'otime' field.
+ * see comments in create_ext2_image.
+ */
+ last_trans = btrfs_timespec_sec(leaf, tspec);
+ total_bytes = btrfs_timespec_nsec(leaf, tspec);
+ total_bytes *= root->sectorsize;
+ btrfs_release_path(ext2_root, &path);
+ if (total_bytes != btrfs_inode_size(leaf, inode)) {
+ fprintf(stderr, "image file size mismatch\n");
+ goto fail;
+ }
+
+ key.objectid = objectid;
+ key.offset = 0;
+ btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
+ ret = btrfs_search_slot(NULL, ext2_root, &key, &path, 0, 0);
+ if (ret != 0) {
+ fprintf(stderr, "unable to find first file extent\n");
+ goto fail;
+ }
+
+ for (offset = 0; offset < total_bytes; ) {
+ leaf = path.nodes[0];
+ if (path.slots[0] >= btrfs_header_nritems(leaf)) {
+ ret = btrfs_next_leaf(root, &path);
+ if (ret != 0)
+ break;
+ continue;
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
+ if (key.objectid != objectid || key.offset != offset ||
+ btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
+ break;
+
+ fi = btrfs_item_ptr(leaf, path.slots[0],
+ struct btrfs_file_extent_item);
+ if (btrfs_file_extent_generation(leaf, fi) > last_trans) {
+ modified = 1;
+ break;
+ }
+ if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
+ break;
+
+ if (offset >= first_free)
+ goto next;
+
+ bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ if (bytenr == 0)
+ break;
+ bytenr += btrfs_file_extent_offset(leaf, fi);
+ num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
+ if (num_bytes > first_free - offset)
+ num_bytes = first_free - offset;
+
+ ret = pread(fd, buf + offset, num_bytes, bytenr);
+ if (ret != num_bytes) {
+ fprintf(stderr, "unable to read required data\n");
+ btrfs_release_path(ext2_root, &path);
+ goto fail;
+ }
+next:
+ offset += btrfs_file_extent_num_bytes(leaf, fi);
+ path.slots[0]++;
+ }
+ btrfs_release_path(ext2_root, &path);
+
+ if (modified) {
+ fprintf(stderr, "image file has been modified\n");
+ goto fail;
+ }
+ if (offset < total_bytes) {
+ fprintf(stderr, "unable to check all file extents\n");
+ goto fail;
+ }
+
+ btrfs_free_fs_root(ext2_root->fs_info, ext2_root);
+ ret = close_ctree(root);
+ if (ret) {
+ fprintf(stderr, "error during close_ctree %d\n", ret);
+ goto fail;
+ }
+
+ ret = pwrite(fd, buf, first_free, 0);
+ if (ret < 0) {
+ fprintf(stderr, "error during pwrite %d\n", ret);
+ goto fail;
+ }
+ /* How to handle this case? */
+ BUG_ON(ret != first_free);
+ ret = fsync(fd);
+ if (ret) {
+ fprintf(stderr, "error during fsync %d\n", ret);
+ goto fail;
+ }
+ close(fd);
+ free(buf);
+ printf("rollback complete.\n");
+ return 0;
+fail:
+ fprintf(stderr, "rollback aborted.\n");
+ return -1;
+}
+
+static void print_usage(void)
+{
+ printf("usage: btrfs-convert [-d] [-r] device\n");
+ printf("\t-d disable data checksum\n");
+ printf("\t-r roll back to ext2fs\n");
exit(1);
}
+
+int main(int argc, char *argv[])
+{
+ int ret;
+ int datacsum = 1;
+ int rollback = 0;
+ char *file;
+
+ while(1) {
+ int c = getopt(argc, argv, "dr");
+ if (c < 0)
+ break;
+ switch(c) {
+ case 'd':
+ datacsum = 0;
+ break;
+ case 'r':
+ rollback = 1;
+ break;
+ default:
+ print_usage();
+ }
+ }
+ argc = argc - optind;
+ if (argc == 1) {
+ file = argv[optind];
+ } else {
+ print_usage();
+ }
+ if (rollback) {
+ ret = do_rollback(file, 0);
+ } else {
+ ret = do_convert(file, datacsum);
+ }
+ return ret;
+}
diff -r 12138d4beeb0 disk-io.c
--- a/disk-io.c Fri Jan 04 11:29:55 2008 -0500
+++ b/disk-io.c Mon Jan 07 23:35:25 2008 +0800
@@ -417,7 +417,13 @@ struct btrfs_root *open_ctree_fd(int fp,
read_extent_buffer(fs_info->sb_buffer, fs_info->fsid,
(unsigned long)btrfs_super_fsid(fs_info->sb_buffer),
BTRFS_FSID_SIZE);
+
disk_super = &fs_info->super_copy;
+ if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
+ sizeof(disk_super->magic))) {
+ printk("No valid btrfs found\n");
+ BUG_ON(1);
+ }
nodesize = btrfs_super_nodesize(disk_super);
leafsize = btrfs_super_leafsize(disk_super);
diff -r 12138d4beeb0 utils.c
--- a/utils.c Fri Jan 04 11:29:55 2008 -0500
+++ b/utils.c Mon Jan 07 23:35:25 2008 +0800
@@ -34,7 +34,6 @@
#include "utils.h"
static u64 reference_root_table[4] = {
- [0] = 0,
[1] = BTRFS_ROOT_TREE_OBJECTID,
[2] = BTRFS_EXTENT_TREE_OBJECTID,
[3] = BTRFS_FS_TREE_OBJECTID,
@@ -143,11 +142,10 @@ int make_btrfs(int fd, u64 blocks[4], u6
btrfs_set_extent_refs(buf, extent_item, 1);
nritems++;
- for (i = 0; i < 4; i++) {
- if (blocks[i] < first_free) {
- BUG_ON(i > 0);
- continue;
- }
+ for (i = 1; i < 4; i++) {
+ BUG_ON(blocks[i] < first_free);
+ BUG_ON(blocks[i] < blocks[i - 1]);
+
/* create extent item */
itemoff = itemoff - sizeof(struct btrfs_extent_item);
btrfs_set_disk_key_objectid(&disk_key, blocks[i]);
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