iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

btrfs: do not start readahead for csum tree when scrubbing non-data block groups

Browse Source 
When scrubbing a stripe of a block group we always start readahead for the
checksums btree and wait for it to complete, however when the blockgroup is
not a data block group (or a mixed block group) it is a waste of time to do
it, since there are no checksums for metadata extents in that btree.

So skip that when the block group does not have the data flag set, saving
some time doing memory allocations, queueing a job in the readahead work
queue, waiting for it to complete and potentially avoiding some IO as well
(when csum tree extents are not in memory already).

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2020-10-12 11:55:26 +01:00 committed by David Sterba
parent a57ad681f1
commit a6889caf6e
1 changed files with 12 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
fs/btrfs/scrub.c
View File

@ -3084,17 +3084,21 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
key_end.offset = (u64)-1;
reada1 = btrfs_reada_add(root, &key, &key_end);
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.type = BTRFS_EXTENT_CSUM_KEY;
key.offset = logical;
key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key_end.type = BTRFS_EXTENT_CSUM_KEY;
key_end.offset = logic_end;
reada2 = btrfs_reada_add(csum_root, &key, &key_end);
if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.type = BTRFS_EXTENT_CSUM_KEY;
key.offset = logical;
key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key_end.type = BTRFS_EXTENT_CSUM_KEY;
key_end.offset = logic_end;
reada2 = btrfs_reada_add(csum_root, &key, &key_end);
} else {
reada2 = NULL;
}
if (!IS_ERR(reada1))
btrfs_reada_wait(reada1);
if (!IS_ERR(reada2))
if (!IS_ERR_OR_NULL(reada2))
btrfs_reada_wait(reada2);