forked from Mirrors/btrfs-progs
btrfs-progs: restore: Do proper mirror iteration in copy_one_extent()
The old code of copy_one_extent() is a mess: - The main loop is implemented using goto - @mirror_num is reset to 1 for each loop - @mirror num check against @num_copies is wrong for decompression error This patch will fix this mess by: - Use read_extent_data() read_extent_data() has all the good wrapping of btrfs_map_block() and length check. This removes a lot of complexity. - Add extra file extent offset check To prevent underflow for memory allocation - Do proper mirror_num check for decompression error Issue: #221 Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Qu Wenruo
David Sterba
parent
2efe160bc7
commit
41ff76b833
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@ -346,8 +346,6 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
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struct extent_buffer *leaf,
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struct btrfs_file_extent_item *fi, u64 pos)
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{
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struct btrfs_multi_bio *multi = NULL;
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struct btrfs_device *device;
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char *inbuf, *outbuf = NULL;
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ssize_t done, total = 0;
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u64 bytenr;
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@ -356,12 +354,10 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
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u64 num_bytes;
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u64 length;
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u64 size_left;
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u64 dev_bytenr;
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u64 offset;
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u64 count = 0;
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u64 cur;
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int compress;
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int ret;
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int dev_fd;
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int mirror_num = 1;
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int num_copies;
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@ -372,14 +368,26 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
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offset = btrfs_file_extent_offset(leaf, fi);
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num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
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size_left = disk_size;
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if (compress == BTRFS_COMPRESS_NONE)
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/* Hole, early exit */
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if (disk_size == 0)
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return 0;
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/* Invalid file extent */
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if ((compress == BTRFS_COMPRESS_NONE && offset >= disk_size) ||
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offset > ram_size) {
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error(
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"invalid data extent offset, offset %llu disk_size %llu ram_size %llu",
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offset, disk_size, ram_size);
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return -EUCLEAN;
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}
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if (compress == BTRFS_COMPRESS_NONE && offset < disk_size) {
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bytenr += offset;
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size_left -= offset;
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}
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if (verbose && offset)
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printf("offset is %Lu\n", offset);
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/* we found a hole */
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if (disk_size == 0)
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return 0;
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inbuf = malloc(size_left);
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if (!inbuf) {
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@ -395,48 +403,28 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
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return -ENOMEM;
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}
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}
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num_copies = btrfs_num_copies(root->fs_info, bytenr, disk_size - offset);
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again:
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length = size_left;
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ret = btrfs_map_block(root->fs_info, READ, bytenr, &length, &multi,
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mirror_num, NULL);
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if (ret) {
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error("cannot map block logical %llu length %llu: %d",
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(unsigned long long)bytenr,
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(unsigned long long)length, ret);
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goto out;
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}
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device = multi->stripes[0].dev;
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dev_fd = device->fd;
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device->total_ios++;
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dev_bytenr = multi->stripes[0].physical;
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free(multi);
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if (size_left < length)
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length = size_left;
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done = pread(dev_fd, inbuf+count, length, dev_bytenr);
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/* Need both checks, or we miss negative values due to u64 conversion */
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if (done < 0 || done < length) {
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num_copies = btrfs_num_copies(root->fs_info, bytenr, length);
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mirror_num++;
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/* mirror_num is 1-indexed, so num_copies is a valid mirror. */
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if (mirror_num > num_copies) {
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ret = -1;
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error("exhausted mirrors trying to read (%d > %d)",
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cur = bytenr;
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while (cur < bytenr + size_left) {
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length = bytenr + size_left - cur;
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ret = read_extent_data(root->fs_info, inbuf + cur - bytenr, cur,
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&length, mirror_num);
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if (ret < 0) {
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mirror_num++;
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if (mirror_num > num_copies) {
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ret = -1;
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error("exhausted mirros trying to read (%d > %d)",
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mirror_num, num_copies);
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goto out;
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goto out;
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}
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fprintf(stderr, "trying another mirror\n");
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continue;
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}
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fprintf(stderr, "Trying another mirror\n");
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goto again;
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cur += length;
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}
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mirror_num = 1;
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size_left -= length;
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count += length;
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bytenr += length;
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if (size_left)
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goto again;
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if (compress == BTRFS_COMPRESS_NONE) {
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while (total < num_bytes) {
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done = pwrite(fd, inbuf+total, num_bytes-total,
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@ -454,13 +442,13 @@ again:
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ret = decompress(root, inbuf, outbuf, disk_size, &ram_size, compress);
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if (ret) {
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num_copies = btrfs_num_copies(root->fs_info, bytenr, length);
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mirror_num++;
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if (mirror_num >= num_copies) {
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if (mirror_num > num_copies) {
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ret = -1;
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goto out;
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}
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fprintf(stderr, "Trying another mirror\n");
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fprintf(stderr,
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"trying another mirror due to decompression error\n");
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goto again;
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}
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