btrfs-progs: Read the whole superblock instead of struct btrfs_super_block

Before the patch, btrfs-progs will only read sizeof(struct
btrfs_super_block) and restore it into super_copy.

This makes checksum check for superblock impossible.  Change it to read
the whole superblock.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/disk-io.c b/disk-io.c
index c3da18c..0f5e8ae 100644 (file)
--- a/disk-io.c
+++ b/disk-io.c
@@ -1328,7 +1328,8 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr,
 {
        u8 fsid[BTRFS_FSID_SIZE];
        int fsid_is_initialized = 0;
-       struct btrfs_super_block buf;
+       char tmp[BTRFS_SUPER_INFO_SIZE];
+       struct btrfs_super_block *buf = (struct btrfs_super_block *)tmp;
        int i;
        int ret;
        int max_super = super_recover ? BTRFS_SUPER_MIRROR_MAX : 1;
@@ -1336,15 +1337,15 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr,
        u64 bytenr;
 
        if (sb_bytenr != BTRFS_SUPER_INFO_OFFSET) {
-               ret = pread64(fd, &buf, sizeof(buf), sb_bytenr);
-               if (ret < sizeof(buf))
+               ret = pread64(fd, buf, BTRFS_SUPER_INFO_SIZE, sb_bytenr);
+               if (ret < BTRFS_SUPER_INFO_SIZE)
                        return -1;
 
-               if (btrfs_super_bytenr(&buf) != sb_bytenr ||
-                   btrfs_super_magic(&buf) != BTRFS_MAGIC)
+               if (btrfs_super_bytenr(buf) != sb_bytenr ||
+                   btrfs_super_magic(buf) != BTRFS_MAGIC)
                        return -1;
 
-               memcpy(sb, &buf, sizeof(*sb));
+               memcpy(sb, buf, BTRFS_SUPER_INFO_SIZE);
                return 0;
        }
 
@@ -1357,22 +1358,22 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr,
 
        for (i = 0; i < max_super; i++) {
                bytenr = btrfs_sb_offset(i);
-               ret = pread64(fd, &buf, sizeof(buf), bytenr);
-               if (ret < sizeof(buf))
+               ret = pread64(fd, buf, BTRFS_SUPER_INFO_SIZE, bytenr);
+               if (ret < BTRFS_SUPER_INFO_SIZE)
                        break;
 
-               if (btrfs_super_bytenr(&buf) != bytenr )
+               if (btrfs_super_bytenr(buf) != bytenr )
                        continue;
                /* if magic is NULL, the device was removed */
-               if (btrfs_super_magic(&buf) == 0 && i == 0)
+               if (btrfs_super_magic(buf) == 0 && i == 0)
                        return -1;
-               if (btrfs_super_magic(&buf) != BTRFS_MAGIC)
+               if (btrfs_super_magic(buf) != BTRFS_MAGIC)
                        continue;
 
                if (!fsid_is_initialized) {
-                       memcpy(fsid, buf.fsid, sizeof(fsid));
+                       memcpy(fsid, buf->fsid, sizeof(fsid));
                        fsid_is_initialized = 1;
-               } else if (memcmp(fsid, buf.fsid, sizeof(fsid))) {
+               } else if (memcmp(fsid, buf->fsid, sizeof(fsid))) {
                        /*
                         * the superblocks (the original one and
                         * its backups) contain data of different
@@ -1381,9 +1382,9 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr,
                        continue;
                }
 
-               if (btrfs_super_generation(&buf) > transid) {
-                       memcpy(sb, &buf, sizeof(*sb));
-                       transid = btrfs_super_generation(&buf);
+               if (btrfs_super_generation(buf) > transid) {
+                       memcpy(sb, buf, BTRFS_SUPER_INFO_SIZE);
+                       transid = btrfs_super_generation(buf);
                }
        }