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authorFilipe David Borba Manana <fdmanana@gmail.com>2013-09-03 12:19:58 +0100
committerChris Mason <chris.mason@fusionio.com>2013-10-16 08:20:03 -0400
commit1bef332a03c19c0142ffd48e061cac7bdd894e70 (patch)
tree00604d868a5b54ea1a2ad46a152ed73ecc272322 /cmds-restore.c
parentdd4d4260d192434a99ca271e18f1e26d6ad6d737 (diff)
Btrfs-progs: fix restore command leaving corrupted files
When there are files that have parts shared with snapshots, the restore command was incorrectly restoring them, as it was not taking into account the offset and number of bytes fields from the file extent item. Besides leaving the recovered file corrupt, it was also inneficient as it read and wrote more data than needed (with each extent copy overwriting portions of the one previously written). The following steps show how to reproduce this corruption issue: $ mkfs.btrfs -f /dev/sdb3 $ mount /dev/sdb3 /mnt/btrfs $ perl -e '$d = "\x41" . ("\x00" x (1024*1024+349)); open($f,">","/mnt/btrfs/foobar"); print $f $d; close($f);' $ du -b /mnt/btrfs/foobar 1048926 /mnt/btrfs/foobar $ md5sum /mnt/btrfs/foobar f9f778f3a7410c40e4ed104a3a63c3c4 /mnt/btrfs/foobar $ btrfs subvolume snapshot /mnt/btrfs /mnt/btrfs/my_snap $ perl -e 'open($f, "+<", "/mnt/btrfs/foobar"); seek($f, 4096, 0); print $f "\xff"; close($f);' $ md5sum /mnt/btrfs/foobar b983fcefd4622a03a78936484c40272b /mnt/btrfs/foobar $ umount /mnt/btrfs $ btrfs restore /dev/sdb3 /tmp/copy $ du -b /tmp/copy/foobar 1048926 /tmp/copy/foobar $ md5sum /tmp/copy/foobar 88db338cbc1c44dfabae083f1ce642d5 /tmp/copy/foobar $ od -t x1 -j 8192 -N 4 /tmp/copy/foobar 0020000 41 00 00 00 0020004 $ mount /dev/sdb3 /mnt/btrfs $ od -t x1 -j 8192 -N 4 /mnt/btrfs/foobar 0020000 00 00 00 00 0020004 $ md5sum /mnt/btrfs/foobar b983fcefd4622a03a78936484c40272b /mnt/btrfs/foobar Tested this change with zlib, lzo compression and file sizes larger than 1GiB, and found no regression or other corruption issues (so far at least). Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'cmds-restore.c')
-rw-r--r--cmds-restore.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/cmds-restore.c b/cmds-restore.c
index 4c874835..2a05eceb 100644
--- a/cmds-restore.c
+++ b/cmds-restore.c
@@ -278,6 +278,7 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
u64 bytenr;
u64 ram_size;
u64 disk_size;
+ u64 num_bytes;
u64 length;
u64 size_left;
u64 dev_bytenr;
@@ -294,7 +295,9 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
disk_size = btrfs_file_extent_disk_num_bytes(leaf, fi);
ram_size = btrfs_file_extent_ram_bytes(leaf, fi);
offset = btrfs_file_extent_offset(leaf, fi);
- size_left = disk_size;
+ num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
+ size_left = num_bytes;
+ bytenr += offset;
if (offset)
printf("offset is %Lu\n", offset);
@@ -302,7 +305,7 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
if (disk_size == 0)
return 0;
- inbuf = malloc(disk_size);
+ inbuf = malloc(size_left);
if (!inbuf) {
fprintf(stderr, "No memory\n");
return -1;
@@ -357,8 +360,8 @@ again:
goto again;
if (compress == BTRFS_COMPRESS_NONE) {
- while (total < ram_size) {
- done = pwrite(fd, inbuf+total, ram_size-total,
+ while (total < num_bytes) {
+ done = pwrite(fd, inbuf+total, num_bytes-total,
pos+total);
if (done < 0) {
ret = -1;
@@ -371,7 +374,7 @@ again:
goto out;
}
- ret = decompress(inbuf, outbuf, disk_size, &ram_size, compress);
+ ret = decompress(inbuf, outbuf, num_bytes, &ram_size, compress);
if (ret) {
num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
bytenr, length);