[PATCH v2 01/14] block: Add blk_validate_atomic_write_op_size()

John Garry
2024-03-04T13:05:18Z

FSes will not check if the BIO submitted for an atomic write adheres to the
request_queue limits, so check in the BIO submission path.

Signed-off-by: John Garry <john.g.garry@oracle.com>
---
We really should return -EINVAL to userspce, so can be have BLK_STS_INVAL
or similar?
block/blk-core.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index de771093b526..a1b095a68498 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -718,6 +718,18 @@ void submit_bio_noacct_nocheck(struct bio *bio)
__submit_bio_noacct(bio);
}

+static blk_status_t blk_validate_atomic_write_op_size(struct request_queue *q,
+ struct bio *bio)
+{
+ if (bio->bi_iter.bi_size > queue_atomic_write_unit_max_bytes(q))
+ return BLK_STS_IOERR;
+
+ if (bio->bi_iter.bi_size % queue_atomic_write_unit_min_bytes(q))
+ return BLK_STS_IOERR;
+
+ return BLK_STS_OK;
+}
+
/**
* submit_bio_noacct - re-submit a bio to the block device layer for I/O
* @bio: The bio describing the location in memory and on the device.
@@ -775,6 +787,11 @@ void submit_bio_noacct(struct bio *bio)
switch (bio_op(bio)) {
case REQ_OP_READ:
case REQ_OP_WRITE:
+ if (bio->bi_opf & REQ_ATOMIC) {
+ status = blk_validate_atomic_write_op_size(q, bio);
+ if (status != BLK_STS_OK)
+ goto end_io;
+ }
break;
case REQ_OP_FLUSH:
/*
--
2.31.1