Ext4 before this patch can issue discards without respecting block
device's discard alignment. Such a discard results in EIO and
kernel logs.
Verified that there were no regressions in xfstests smoke tests.
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx>
---
fs/ext4/mballoc.c | 32 +++++++++++++++++++++-----------
include/linux/blkdev.h | 7 +++++++
2 files changed, 28 insertions(+), 11 deletions(-)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 30d5d97548c4..a591a3ab93d3 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2786,20 +2786,30 @@ static inline int ext4_issue_discard(struct super_block *sb,
ext4_group_t block_group, ext4_grpblk_t cluster, int count,
struct bio **biop)
{
- ext4_fsblk_t discard_block;
-
- discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
- ext4_group_first_block_no(sb, block_group));
- count = EXT4_C2B(EXT4_SB(sb), count);
+ unsigned long long discard_start, discard_len, alignment, granularity,
+ aligned_discard_start;
+
+ granularity = max(bdev_discard_granularity(sb->s_bdev), 1 << 9);
+ alignment = max_t(int, bdev_logical_block_size(sb->s_bdev),
+ bdev_discard_alignment(sb->s_bdev));
+ discard_start = (EXT4_C2B(EXT4_SB(sb), cluster) +
+ ext4_group_first_block_no(sb, block_group)) <<
+ sb->s_blocksize_bits;
+ discard_len = EXT4_C2B(EXT4_SB(sb), count) << sb->s_blocksize_bits;
+ aligned_discard_start = round_up(discard_start, alignment);
+ discard_len -= min(discard_len, aligned_discard_start - discard_start);
+ discard_len = round_down(discard_len, granularity);
+ if (discard_len >> 9 == 0)
+ return 0;
trace_ext4_discard_blocks(sb,
- (unsigned long long) discard_block, count);
- if (biop) {
+ aligned_discard_start >> sb->s_blocksize_bits,
+ discard_len >> (sb->s_blocksize_bits));
+ if (biop)
return __blkdev_issue_discard(sb->s_bdev,
- (sector_t)discard_block << (sb->s_blocksize_bits - 9),
- (sector_t)count << (sb->s_blocksize_bits - 9),
+ aligned_discard_start >> 9, discard_len >> 9,
GFP_NOFS, 0, biop);
- } else
- return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
+ return sb_issue_discard(sb, aligned_discard_start, discard_len,
+ GFP_NOFS, 0);
}
static void ext4_free_data_in_buddy(struct super_block *sb,
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8fd900998b4e..f448b3498336 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1431,6 +1431,13 @@ static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector
return offset << SECTOR_SHIFT;
}
+static inline int bdev_discard_granularity(struct block_device *bdev)
+{
+ struct request_queue *q = bdev_get_queue(bdev);
+
+ return q ? q->limits.discard_granularity : 0;
+}
+
static inline int bdev_discard_alignment(struct block_device *bdev)
{
struct request_queue *q = bdev_get_queue(bdev);
--
2.27.0.278.ge193c7cf3a9-goog
