From 6acf7860dcc79ed045cc9e6a79c8a8bb6959dba7 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 24 Feb 2026 06:21:44 -0800 Subject: zloop: advertise a volatile write cache Zloop is file system backed and thus needs to sync the underlying file system to persist data. Set BLK_FEAT_WRITE_CACHE so that the block layer actually send flush commands, and fix the flush implementation as sync_filesystem requires s_umount to be held and the code currently misses that. Fixes: eb0570c7df23 ("block: new zoned loop block device driver") Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Signed-off-by: Jens Axboe --- drivers/block/zloop.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/drivers/block/zloop.c b/drivers/block/zloop.c index 8e334f5025fc..ae9bf2a85c21 100644 --- a/drivers/block/zloop.c +++ b/drivers/block/zloop.c @@ -542,6 +542,21 @@ out: zloop_put_cmd(cmd); } +/* + * Sync the entire FS containing the zone files instead of walking all files. + */ +static int zloop_flush(struct zloop_device *zlo) +{ + struct super_block *sb = file_inode(zlo->data_dir)->i_sb; + int ret; + + down_read(&sb->s_umount); + ret = sync_filesystem(sb); + up_read(&sb->s_umount); + + return ret; +} + static void zloop_handle_cmd(struct zloop_cmd *cmd) { struct request *rq = blk_mq_rq_from_pdu(cmd); @@ -562,11 +577,7 @@ static void zloop_handle_cmd(struct zloop_cmd *cmd) zloop_rw(cmd); return; case REQ_OP_FLUSH: - /* - * Sync the entire FS containing the zone files instead of - * walking all files - */ - cmd->ret = sync_filesystem(file_inode(zlo->data_dir)->i_sb); + cmd->ret = zloop_flush(zlo); break; case REQ_OP_ZONE_RESET: cmd->ret = zloop_reset_zone(zlo, rq_zone_no(rq)); @@ -981,7 +992,8 @@ static int zloop_ctl_add(struct zloop_options *opts) struct queue_limits lim = { .max_hw_sectors = SZ_1M >> SECTOR_SHIFT, .chunk_sectors = opts->zone_size, - .features = BLK_FEAT_ZONED, + .features = BLK_FEAT_ZONED | BLK_FEAT_WRITE_CACHE, + }; unsigned int nr_zones, i, j; struct zloop_device *zlo; -- cgit v1.2.3