diff options
| -rw-r--r-- | include/os/linux/kernel/linux/blkdev_compat.h | 27 | ||||
| -rw-r--r-- | module/os/linux/zfs/vdev_disk.c | 7 |
2 files changed, 32 insertions, 2 deletions
diff --git a/include/os/linux/kernel/linux/blkdev_compat.h b/include/os/linux/kernel/linux/blkdev_compat.h index b0f398354e4f..658f546213de 100644 --- a/include/os/linux/kernel/linux/blkdev_compat.h +++ b/include/os/linux/kernel/linux/blkdev_compat.h @@ -94,6 +94,33 @@ blk_queue_set_write_cache(struct request_queue *q, bool wc, bool fua) #endif } +/* + * Detect if a device has a write cache. Used to set the intial value for the + * vdev nowritecache flag. + * + * 4.10: QUEUE_FLAG_WC added. Initialised by the driver, but can be changed + * later by the operator. If not set, kernel will return flush requests + * immediately without doing anything. + * 6.6: QUEUE_FLAG_HW_WC added. Initialised by the driver, can't be changed. + * Only controls if the operator is allowed to change _WC. Initial version + * buggy; aliased to QUEUE_FLAG_FUA, so unuseable. + * 6.6.10, 6.7: QUEUE_FLAG_HW_WC fixed. + * + * Older than 4.10 we just assume write cache, and let the normal flush fail + * detection apply. + */ +static inline boolean_t +zfs_bdev_has_write_cache(struct block_device *bdev) +{ +#if defined(QUEUE_FLAG_HW_WC) && QUEUE_FLAG_HW_WC != QUEUE_FLAG_FUA + return (test_bit(QUEUE_FLAG_HW_WC, &bdev_get_queue(bdev)->queue_flags)); +#elif defined(QUEUE_FLAG_WC) + return (test_bit(QUEUE_FLAG_WC, &bdev_get_queue(bdev)->queue_flags)); +#else + return (B_TRUE); +#endif +} + static inline void blk_queue_set_read_ahead(struct request_queue *q, unsigned long ra_pages) { diff --git a/module/os/linux/zfs/vdev_disk.c b/module/os/linux/zfs/vdev_disk.c index 2cea61a6294c..463c5f705102 100644 --- a/module/os/linux/zfs/vdev_disk.c +++ b/module/os/linux/zfs/vdev_disk.c @@ -429,8 +429,11 @@ vdev_disk_open(vdev_t *v, uint64_t *psize, uint64_t *max_psize, /* Determine the logical block size */ int logical_block_size = bdev_logical_block_size(bdev); - /* Clear the nowritecache bit, causes vdev_reopen() to try again. */ - v->vdev_nowritecache = B_FALSE; + /* + * If the device has a write cache, clear the nowritecache flag, + * so that we start issuing flush requests again. + */ + v->vdev_nowritecache = !zfs_bdev_has_write_cache(bdev); /* Set when device reports it supports TRIM. */ v->vdev_has_trim = bdev_discard_supported(bdev); |