v1->v2:
Various changes suggested by Nicokay. Thanks. For specific changes
pls ref to the patch.
Patch 1-4/8 are preparatory patches adds cleanups and nonstatic requisites.
Patch 5/8 makes sure that all copies of the superblock have the same fsid
when we scan the device.
Patch 6/8 verifies superblock csum when we read it in the scan context.
Patch 7/8 fixes a bug that we weren't verifying the superblock csum for
the non-latest_bdev.
And 8/8 patch drops the redundant invalidate_bdev() call during mount.
There is a btrfs-progs patch which is a kind of related, as its found that
we weren't wiping the non-overwritten superblock, so it could cause
confusion during the superblock recovery process. So the patch btrfs-progs
1/1 adds code to wipe superblock if we aren't overwriting it.
Now since kernel patch 5/8 checks if all the superblock copies are
pointing to the same fsid on the disk, so the scan will fail if without
the above 1/1 btrfs-progs, as in the example below [1]. However the simple
workaround is to wipe the superblock manually [2] or apply the btrfs-progs
patch below.
[1]
mkfs.btrfs -qf /dev/sdb <-- 1T disk
mkfs.btrfs -b 256M /dev/sdb
ERROR: device scan failed on /dev/sdb
[2]
dd if=/dev/zero of=<dev> seek=274877906944 ibs=1 obs=1 count4K
Unfortunately, the error messages should have been failed to register
[3] device into the kernel to be more appropriate to the error.
[3]
ret = ioctl(fd, BTRFS_IOC_SCAN_DEV, &args);
if (ret < 0) {
error("device scan failed on '%s': %m", fname);
ret = -errno;
}
Patches 1-7/8 were sent independently before. And I found few more things
to fix alongs the line, and since they are related, so I am sending these
all together. Also, as there are minor changes, like in pr_err strings,
and splitting the unrelated changes into a separate patch, so though I am
thankful for the received reviewed-by, I couldn't include them here. Sorry.
Finally, here I am including the function relations [4] so that it will help
to review the code. And this flow is before these patches were applied.
[4]
In the long term, I suggest deprecating ioctl args which pass device path
(where possible), like in delete-device/replace. And
btrfs_read_dev_one_super() should replace btrfs_read_disk_super()
delete-device/replace:
btrfs_rm_device() || btrfs_dev_replace_by_ioctl()
|_btrfs_find_device_by_devspec()
|_btrfs_find_device_missing_or_by_path()
|_btrfs_find_device_by_path()
|_btrfs_get_bdev_and_sb()
|_btrfs_read_dev_super()
|_btrfs_read_dev_one_super()
|___bread()
btrfs_mount_root()
|
|_btrfs_parse_early_options (-o device only)
| |_btrfs_scan_one_device
| |_btrfs_read_disk_super()
| |_read_cache_page_gfp()
|
|_btrfs_scan_one_device(mount-arg-dev only)
| |_btrfs_read_disk_super()
| |_read_cache_page_gfp()
|
|
|_btrfs_open_devices(fsid:all)
| |_btrfs_open_one_device()
| |_btrfs_get_bdev_and_sb() <--- invalidate_bdev(fsid:all)
| |_btrfs_read_dev_super()
| |_btrfs_read_dev_one_super()
| |___bread()
|
|_btrfs_fill_super()
|_btrfs_open_ctree() <-- invalidate_bdev(latest_bdev) <-- redundant
|_btrfs_read_dev_super(latest_bdev only)
| |_btrfs_read_dev_one_super(latest_bdev only)
| |___bread(latest_bdev)
|
|_btrfs_check_super_csum(latest_bdev only) [*]
|
|_btrfs_read_chunk_tree
| |_read_one_dev()
| |_open_seed_devices()
| |_btrfs_open_devices(fs_devices->seed only)
scan/ready
|
|_btrfs_scan_one_device(ioctl-arg-dev only)
|_btrfs_read_disk_super()
|_read_cache_page_gfp()
Anand Jain (8):
btrfs: cleanup btrfs_check_super_csum() for better code flow
btrfs: return required error from btrfs_check_super_csum
btrfs: cleanup btrfs_read_disk_super() to return std error
btrfs: make btrfs_check_super_csum() non static
btrfs: check if the fsid in the primary sb and copy sb are same
btrfs: verify checksum when superblock is read for scan
btrfs: verify checksum for all devices in mount context
btrfs: drop the redundant invalidate_bdev()
fs/btrfs/disk-io.c | 72 +++++++++++++++++++++++-----------------------
fs/btrfs/disk-io.h | 1 +
fs/btrfs/volumes.c | 84 ++++++++++++++++++++++++++++++++++++++++++------------
3 files changed, 102 insertions(+), 55 deletions(-)
Anand Jain (1):
btrfs-progs: wipe copies of the stale superblock beyond -b size
utils.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
--
2.7.0
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