| Message ID | 1403836494-26904-1-git-send-email-quwenruo@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
I'm very sorry that this patch breaks the open_ctree(). 1) pread() only reads sizeof(struct btrfs_super_block), not BTRFS_SUPER_INFO_SIZE. Which makes csum always dismatch. 2) memcpy() uses wrong src(should be 'buf' not 'sb'). I'll send v2 version patch soon. Thanks, Qu -------- Original Message -------- Subject: [PATCH] btrfs-progs: Check superblock's checksum in btrfs-progs. From: Qu Wenruo <quwenruo@cn.fujitsu.com> To: linux-btrfs@vger.kernel.org Date: 2014?06?27? 10:34 > Btrfs-progs will read the superblock without checking the checksum. > When all superblocks are corrupted, continuing will cause disaster. > > So this patch will add checksum check for btrfs-progs when reading > superblocks. > > Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> > --- > disk-io.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/disk-io.c b/disk-io.c > index 8db0335..3524834 100644 > --- a/disk-io.c > +++ b/disk-io.c > @@ -990,7 +990,8 @@ int btrfs_scan_fs_devices(int fd, const char *path, > ret = btrfs_scan_one_device(fd, path, fs_devices, > &total_devs, sb_bytenr); > if (ret) { > - fprintf(stderr, "No valid Btrfs found on %s\n", path); > + fprintf(stderr, "No valid Btrfs found or all superblock are corrupted on %s\n", > + path); > return ret; > } > > @@ -1100,7 +1101,7 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path, > else > ret = btrfs_read_dev_super(fp, disk_super, sb_bytenr); > if (ret) { > - printk("No valid btrfs found\n"); > + fprintf(stderr, "No valid btrfs found or all super blocks are corrupted\n"); > goto out_devices; > } > > @@ -1191,6 +1192,8 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr) > int ret; > u64 transid = 0; > u64 bytenr; > + u32 crc; > + char crc_result[BTRFS_CSUM_SIZE]; > > if (sb_bytenr != BTRFS_SUPER_INFO_OFFSET) { > ret = pread64(fd, &buf, sizeof(buf), sb_bytenr); > @@ -1226,6 +1229,14 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr) > if (btrfs_super_magic(&buf) != BTRFS_MAGIC) > continue; > > + /* check if the superblock is damaged */ > + crc = ~(u32)0; > + crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE, > + crc, BTRFS_SUPER_INFO_SIZE - > + BTRFS_CSUM_SIZE); > + btrfs_csum_final(crc, crc_result); > + if (memcmp(crc_result, sb->csum, BTRFS_CSUM_SIZE)) > + continue; > if (!fsid_is_initialized) { > memcpy(fsid, buf.fsid, sizeof(fsid)); > fsid_is_initialized = 1; -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/disk-io.c b/disk-io.c index 8db0335..3524834 100644 --- a/disk-io.c +++ b/disk-io.c @@ -990,7 +990,8 @@ int btrfs_scan_fs_devices(int fd, const char *path, ret = btrfs_scan_one_device(fd, path, fs_devices, &total_devs, sb_bytenr); if (ret) { - fprintf(stderr, "No valid Btrfs found on %s\n", path); + fprintf(stderr, "No valid Btrfs found or all superblock are corrupted on %s\n", + path); return ret; } @@ -1100,7 +1101,7 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path, else ret = btrfs_read_dev_super(fp, disk_super, sb_bytenr); if (ret) { - printk("No valid btrfs found\n"); + fprintf(stderr, "No valid btrfs found or all super blocks are corrupted\n"); goto out_devices; } @@ -1191,6 +1192,8 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr) int ret; u64 transid = 0; u64 bytenr; + u32 crc; + char crc_result[BTRFS_CSUM_SIZE]; if (sb_bytenr != BTRFS_SUPER_INFO_OFFSET) { ret = pread64(fd, &buf, sizeof(buf), sb_bytenr); @@ -1226,6 +1229,14 @@ int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr) if (btrfs_super_magic(&buf) != BTRFS_MAGIC) continue; + /* check if the superblock is damaged */ + crc = ~(u32)0; + crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE, + crc, BTRFS_SUPER_INFO_SIZE - + BTRFS_CSUM_SIZE); + btrfs_csum_final(crc, crc_result); + if (memcmp(crc_result, sb->csum, BTRFS_CSUM_SIZE)) + continue; if (!fsid_is_initialized) { memcpy(fsid, buf.fsid, sizeof(fsid)); fsid_is_initialized = 1;
Btrfs-progs will read the superblock without checking the checksum. When all superblocks are corrupted, continuing will cause disaster. So this patch will add checksum check for btrfs-progs when reading superblocks. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> --- disk-io.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)