112 lines
3.6 KiB
Diff
112 lines
3.6 KiB
Diff
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From 18d8ff57c3cd9ee31829b19fcd6ca57ed201720a Mon Sep 17 00:00:00 2001
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From: Filipe David Borba Manana <fdmanana@gmail.com>
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Date: Tue, 3 Sep 2013 12:19:58 +0100
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Subject: [PATCH 57/62] Btrfs-progs: fix restore command leaving corrupted
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files
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When there are files that have parts shared with snapshots, the
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restore command was incorrectly restoring them, as it was not
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taking into account the offset and number of bytes fields from
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the file extent item. Besides leaving the recovered file corrupt,
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it was also inneficient as it read and wrote more data than needed
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(with each extent copy overwriting portions of the one previously
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written).
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The following steps show how to reproduce this corruption issue:
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$ mkfs.btrfs -f /dev/sdb3
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$ mount /dev/sdb3 /mnt/btrfs
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$ perl -e '$d = "\x41" . ("\x00" x (1024*1024+349)); open($f,">","/mnt/btrfs/foobar"); print $f $d; close($f);'
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$ du -b /mnt/btrfs/foobar
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1048926 /mnt/btrfs/foobar
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$ md5sum /mnt/btrfs/foobar
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f9f778f3a7410c40e4ed104a3a63c3c4 /mnt/btrfs/foobar
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$ btrfs subvolume snapshot /mnt/btrfs /mnt/btrfs/my_snap
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$ perl -e 'open($f, "+<", "/mnt/btrfs/foobar"); seek($f, 4096, 0); print $f "\xff"; close($f);'
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$ md5sum /mnt/btrfs/foobar
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b983fcefd4622a03a78936484c40272b /mnt/btrfs/foobar
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$ umount /mnt/btrfs
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$ btrfs restore /dev/sdb3 /tmp/copy
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$ du -b /tmp/copy/foobar
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1048926 /tmp/copy/foobar
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$ md5sum /tmp/copy/foobar
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88db338cbc1c44dfabae083f1ce642d5 /tmp/copy/foobar
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$ od -t x1 -j 8192 -N 4 /tmp/copy/foobar
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0020000 41 00 00 00
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0020004
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$ mount /dev/sdb3 /mnt/btrfs
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$ od -t x1 -j 8192 -N 4 /mnt/btrfs/foobar
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0020000 00 00 00 00
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0020004
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$ md5sum /mnt/btrfs/foobar
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b983fcefd4622a03a78936484c40272b /mnt/btrfs/foobar
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Tested this change with zlib, lzo compression and file sizes larger
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than 1GiB, and found no regression or other corruption issues (so far
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at least).
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Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
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Signed-off-by: David Sterba <dsterba@suse.cz>
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Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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---
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cmds-restore.c | 13 ++++++++-----
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1 file changed, 8 insertions(+), 5 deletions(-)
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diff --git a/cmds-restore.c b/cmds-restore.c
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index e48df40320f6..9688599742d9 100644
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--- a/cmds-restore.c
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+++ b/cmds-restore.c
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@@ -272,6 +272,7 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
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u64 bytenr;
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u64 ram_size;
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u64 disk_size;
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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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@@ -288,7 +289,9 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
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disk_size = btrfs_file_extent_disk_num_bytes(leaf, fi);
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ram_size = btrfs_file_extent_ram_bytes(leaf, fi);
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offset = btrfs_file_extent_offset(leaf, fi);
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- size_left = disk_size;
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+ num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
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+ size_left = num_bytes;
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+ bytenr += offset;
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if (offset)
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printf("offset is %Lu\n", offset);
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@@ -296,7 +299,7 @@ static int copy_one_extent(struct btrfs_root *root, int fd,
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if (disk_size == 0)
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return 0;
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- inbuf = malloc(disk_size);
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+ inbuf = malloc(size_left);
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if (!inbuf) {
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fprintf(stderr, "No memory\n");
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return -1;
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@@ -351,8 +354,8 @@ again:
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goto again;
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if (compress == BTRFS_COMPRESS_NONE) {
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- while (total < ram_size) {
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- done = pwrite(fd, inbuf+total, ram_size-total,
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+ while (total < num_bytes) {
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+ done = pwrite(fd, inbuf+total, num_bytes-total,
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pos+total);
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if (done < 0) {
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ret = -1;
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@@ -365,7 +368,7 @@ again:
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goto out;
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}
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- ret = decompress(inbuf, outbuf, disk_size, &ram_size, compress);
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+ ret = decompress(inbuf, outbuf, num_bytes, &ram_size, compress);
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if (ret) {
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num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
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bytenr, length);
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--
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1.8.3.1
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