c8h4/btrfs-progs
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

btrfs-progs: mkfs: use proper zoned compatible write for bgt feature

Browse source 
[BUG]
There is a bug report that mkfs.btrfs can not specify block-group-tree
feature along with zoned devices:

  # mkfs.btrfs /dev/nullb0 -O block-group-tree,zoned
  btrfs-progs v6.7.1
  See https://btrfs.readthedocs.io for more information.

  Resetting device zones /dev/nullb0 (40 zones) ...
  NOTE: several default settings have changed in version 5.15, please make sure
        this does not affect your deployments:
        - DUP for metadata (-m dup)
        - enabled no-holes (-O no-holes)
        - enabled free-space-tree (-R free-space-tree)

  ERROR: error during mkfs: Invalid argument

[CAUSE]
During mkfs, we need to write all the 7 or 8 tree blocks into the
metadata zone, and since it's zoned device, we need to fulfill all the
requirement for zoned writes, including:

- All writes must be in sequential bytenr
- Buffer must be aligned to sector size

The sequential bytenr requirement is already met by the mkfs design, but
the second requirement on memory alignment is never met for metadata, as
we put the contents of a leaf in extent_buffer::data[], which is after a
lot of small members.

Thus metadata IO buffer would never be aligned to sector size (normally
4K).
And we require btrfs_pwrite() and btrfs_pread() to handle the memory
alignment for us.

However in create_block_group_tree() we didn't use btrfs_pwrite(), but
plain pwrite() call directly, which would lead to -EINVAL error due to
memory alignment problem.

[FIX]
Just call btrfs_pwrite() instead of the plain pwrite() in
create_block_group_tree().

Issue: #765
Pull-request: #767
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2024-03-26 10:52:43 +10:30 committed by David Sterba
parent b310b231f1
commit 9de25ff2ae
1 changed files with 2 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
mkfs/common.c
View file

@ -249,8 +249,8 @@ static int create_block_group_tree(int fd, struct btrfs_mkfs_config *cfg,
btrfs_set_header_nritems(buf, 1);
csum_tree_block_size(buf, btrfs_csum_type_size(cfg->csum_type), 0,
cfg->csum_type);
ret = pwrite(fd, buf->data, cfg->nodesize,
cfg->blocks[MKFS_BLOCK_GROUP_TREE]);
ret = btrfs_pwrite(fd, buf->data, cfg->nodesize,
cfg->blocks[MKFS_BLOCK_GROUP_TREE], cfg->zone_size);
if (ret != cfg->nodesize)
return ret < 0 ? -errno : -EIO;
return 0;