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authorMikulas Patocka <mpatocka@redhat.com>2017-07-19 11:23:40 -0400
committerMike Snitzer <snitzer@redhat.com>2017-07-19 18:44:18 -0400
commit9dd59727dbc21d33a9add4c5b308a5775cd5a6ef (patch)
treed0ff52601eb09c36f0bd7d4fe02d01f90e0b0768 /drivers/md/dm-integrity.c
parentLinux v4.13-rc1 (diff)
downloadlinux-dev-9dd59727dbc21d33a9add4c5b308a5775cd5a6ef.tar.xz
linux-dev-9dd59727dbc21d33a9add4c5b308a5775cd5a6ef.zip
dm integrity: fix inefficient allocation of journal space
When using a block size greater than 512 bytes, the dm-integrity target allocates journal space inefficiently. It allocates one journal entry for each 512-byte chunk of data, fills an entry for each block of data and leaves the remaining entries unused. This issue doesn't cause data corruption, but all the unused journal entries degrade performance severely. For example, with 4k blocks and an 8k bio, it would allocate 16 journal entries but only use 2 entries. The remaining 14 entries were left unused. Fix this by adding the missing 'log2_sectors_per_block' shifts that are required to have each journal entry map to a full block. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Fixes: 7eada909bfd7 ("dm: add integrity target") Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-integrity.c')
-rw-r--r--drivers/md/dm-integrity.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 1b224aa9cf15..4b2fd524e38d 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1587,16 +1587,18 @@ retry:
if (likely(ic->mode == 'J')) {
if (dio->write) {
unsigned next_entry, i, pos;
- unsigned ws, we;
+ unsigned ws, we, range_sectors;
- dio->range.n_sectors = min(dio->range.n_sectors, ic->free_sectors);
+ dio->range.n_sectors = min(dio->range.n_sectors,
+ ic->free_sectors << ic->sb->log2_sectors_per_block);
if (unlikely(!dio->range.n_sectors))
goto sleep;
- ic->free_sectors -= dio->range.n_sectors;
+ range_sectors = dio->range.n_sectors >> ic->sb->log2_sectors_per_block;
+ ic->free_sectors -= range_sectors;
journal_section = ic->free_section;
journal_entry = ic->free_section_entry;
- next_entry = ic->free_section_entry + dio->range.n_sectors;
+ next_entry = ic->free_section_entry + range_sectors;
ic->free_section_entry = next_entry % ic->journal_section_entries;
ic->free_section += next_entry / ic->journal_section_entries;
ic->n_uncommitted_sections += next_entry / ic->journal_section_entries;