From 6eba9002956ac40db87d42fb653a0524dc568810 Mon Sep 17 00:00:00 2001 From: Goffredo Baroncelli Date: Tue, 4 Sep 2012 19:59:26 +0200 Subject: [PATCH 1/1] Correct un-initialized fsid variable --- disk-io.c | 20 ++++++++++++++++---- 1 files changed, 16 insertions(+), 4 deletions(-) diff --git a/disk-io.c b/disk-io.c index b21a87f..0395205 100644 --- a/disk-io.c +++ b/disk-io.c @@ -910,6 +910,7 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr, 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; int i; int ret; @@ -936,15 +937,26 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr) if (ret < sizeof(buf)) break; - if (btrfs_super_bytenr(&buf) != bytenr || - strncmp((char *)(&buf.magic), BTRFS_MAGIC, + if (btrfs_super_bytenr(&buf) != bytenr ) + continue; + /* if magic is NULL, the device was removed */ + if (buf.magic == 0 && i == 0) + return -1; + if (strncmp((char *)(&buf.magic), BTRFS_MAGIC, sizeof(buf.magic))) continue; - if (i == 0) + if (!fsid_is_initialized) { memcpy(fsid, buf.fsid, sizeof(fsid)); - else if (memcmp(fsid, buf.fsid, sizeof(fsid))) + fsid_is_initialized = 1; + } else if (memcmp(fsid, buf.fsid, sizeof(fsid))) { + /* + * the superblocks (the original one and + * its backups) contain data of different + * filesystems -> the super cannot be trusted + */ continue; + } if (btrfs_super_generation(&buf) > transid) { memcpy(sb, &buf, sizeof(*sb)); -- 1.7.7.6