btrfs-progs: convert: Fix migrate_super_block() to work with 64k sectorsize

migrate_super_block() uses sectorsize to refer to the size of the
superblock. Hence on 64k sectorsize filesystems, it ends up computing
checksum beyond the super block length (i.e.
BTRFS_SUPER_INFO_SIZE). This commit fixes the bug by using
BTRFS_SUPER_INFO_SIZE instead of sectorsize of the underlying
filesystem.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/convert/main.c b/convert/main.c
index 1148a369f736c9032c86270ab2d0c5f8d5095b00..fd6f77b2bf4b6bce9117b219cc302375a1fe3a0a 100644 (file)
--- a/convert/main.c
+++ b/convert/main.c
@@ -1360,7 +1360,7 @@ err:
 /*
  * Migrate super block to its default position and zero 0 ~ 16k
  */
-static int migrate_super_block(int fd, u64 old_bytenr, u32 sectorsize)
+static int migrate_super_block(int fd, u64 old_bytenr)
 {
        int ret;
        struct extent_buffer *buf;
@@ -1368,13 +1368,13 @@ static int migrate_super_block(int fd, u64 old_bytenr, u32 sectorsize)
        u32 len;
        u32 bytenr;
 
-       buf = malloc(sizeof(*buf) + sectorsize);
+       buf = malloc(sizeof(*buf) + BTRFS_SUPER_INFO_SIZE);
        if (!buf)
                return -ENOMEM;
 
-       buf->len = sectorsize;
-       ret = pread(fd, buf->data, sectorsize, old_bytenr);
-       if (ret != sectorsize)
+       buf->len = BTRFS_SUPER_INFO_SIZE;
+       ret = pread(fd, buf->data, BTRFS_SUPER_INFO_SIZE, old_bytenr);
+       if (ret != BTRFS_SUPER_INFO_SIZE)
                goto fail;
 
        super = (struct btrfs_super_block *)buf->data;
@@ -1382,19 +1382,20 @@ static int migrate_super_block(int fd, u64 old_bytenr, u32 sectorsize)
        btrfs_set_super_bytenr(super, BTRFS_SUPER_INFO_OFFSET);
 
        csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
-       ret = pwrite(fd, buf->data, sectorsize, BTRFS_SUPER_INFO_OFFSET);
-       if (ret != sectorsize)
+       ret = pwrite(fd, buf->data, BTRFS_SUPER_INFO_SIZE,
+               BTRFS_SUPER_INFO_OFFSET);
+       if (ret != BTRFS_SUPER_INFO_SIZE)
                goto fail;
 
        ret = fsync(fd);
        if (ret)
                goto fail;
 
-       memset(buf->data, 0, sectorsize);
+       memset(buf->data, 0, BTRFS_SUPER_INFO_SIZE);
        for (bytenr = 0; bytenr < BTRFS_SUPER_INFO_OFFSET; ) {
                len = BTRFS_SUPER_INFO_OFFSET - bytenr;
-               if (len > sectorsize)
-                       len = sectorsize;
+               if (len > BTRFS_SUPER_INFO_SIZE)
+                       len = BTRFS_SUPER_INFO_SIZE;
                ret = pwrite(fd, buf->data, len, bytenr);
                if (ret != len) {
                        fprintf(stderr, "unable to zero fill device\n");
@@ -2519,7 +2520,7 @@ static int do_convert(const char *devname, int datacsum, int packing,
         * If this step succeed, we get a mountable btrfs. Otherwise
         * the source fs is left unchanged.
         */
-       ret = migrate_super_block(fd, mkfs_cfg.super_bytenr, blocksize);
+       ret = migrate_super_block(fd, mkfs_cfg.super_bytenr);
        if (ret) {
                error("unable to migrate super block: %d", ret);
                goto fail;