On 28.03.2018 02:39, Anand Jain wrote: > During the scan context, we aren't verifying the superblock- > checksum when read. > This patch fixes it by adding the checksum verification function > btrfs_check_super_csum() in the function btrfs_read_disk_super(). > And makes device scan to error fail if the primary superblock csum > is wrong, whereas if the copy-superblock csum is wrong it will just > just report mismatch and continue mount/scan as usual. When the
Where in this patch do you deal with the secondary sb. btrfs_read_disk_super verifies only the primary sb which corresponds to the first part of the sentence. But I'm confused about the second? I also think that 4/8 should be merged into this one. > mount is successful We anyway overwrite all superblocks upon unmount. > > The context in which this will be called is - device scan, device ready, > and mount -o device option. > > Test script: > > Corrupt primary superblock and check if device scan and mount > fails: > mkfs.btrfs -fq /dev/sdc > dd if=/dev/urandom of=/dev/sdc ibs=1 obs=1 count=1 seek=64K > btrfs dev scan /dev/sdc > mount /dev/sdc /btrfs > > Corrupt secondary superblock and check if device scan and mount > is succcessful, check for the dmesg for errors. > mkfs.btrfs -fq /dev/sdc > dd if=/dev/urandom of=/dev/sdc ibs=1 obs=1 count=1 seek=67108864 > btrfs dev scan /dev/sdc > mount /dev/sdc /btrfs > > Signed-off-by: Anand Jain <[email protected]> > --- > v1->v2: > changed title. > use explicit (< 0) check for %errr. > Un-split pr_err() string. > Fix typo in the git commit log. > Move the csum check after bytenr and btrfs magic verified. > > fs/btrfs/volumes.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index b099823f60d1..eda86ba258fc 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -1149,6 +1149,7 @@ static int btrfs_read_disk_super(struct block_device > *bdev, u64 bytenr, > struct page **page, > struct btrfs_super_block **disk_super) > { > + int err; > void *p; > pgoff_t index; > > @@ -1183,6 +1184,18 @@ static int btrfs_read_disk_super(struct block_device > *bdev, u64 bytenr, > return -EINVAL; > } > > + err = btrfs_check_super_csum((char *) *disk_super); > + if (err < 0) { > + if (err == -EINVAL) > + pr_err("BTRFS error (device %pg): unsupported checksum > type, bytenr=%llu", > + bdev, bytenr); > + else > + pr_err("BTRFS error (device %pg): superblock checksum > failed, bytenr=%llu", > + bdev, bytenr); > + btrfs_release_disk_super(*page); > + return err; > + } > + > if ((*disk_super)->label[0] && > (*disk_super)->label[BTRFS_LABEL_SIZE - 1]) > (*disk_super)->label[BTRFS_LABEL_SIZE - 1] = '\0'; > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
