From: Niklas Cassel <[email protected]> For zoned block devices with SWR zones, the order of the writes must be maintained to avoid write not at write pointer errors. Thus, cache.direct=on must be used to bypass the page cache, since the page cache uses write-back caching, where the physical order of the writes is not guaranteed.
There is already a check for cache.direct=on in raw_open_common(), however, this check is done before raw_refresh_zoned_limits() has been called (which initializes bs->bl.zoned), so it is currently dead code. Fix this by moving the check to raw_refresh_zoned_limits(), such that the check is done after bs->bl.zoned has been initialized. Reviewed-by: Damien Le Moal <[email protected]> Reviewed-by: Dmitry Fomichev <[email protected]> Fixes: 774c726ceb2a ("block: add zoned BlockDriver check to block layer") Signed-off-by: Niklas Cassel <[email protected]> Reviewed-by: Stefan Hajnoczi <[email protected]> Reviewed-by: Johannes Thumshirn <[email protected]> Message-ID: <[email protected]> Signed-off-by: Stefan Hajnoczi <[email protected]> --- block/file-posix.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 3c985da94f5..01037f4b5c3 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -793,18 +793,6 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, goto fail; } } -#ifdef CONFIG_BLKZONED - /* - * The kernel page cache does not reliably work for writes to SWR zones - * of zoned block device because it can not guarantee the order of writes. - */ - if ((bs->bl.zoned != BLK_Z_NONE) && - (!(s->open_flags & O_DIRECT))) { - error_setg(errp, "The driver supports zoned devices, and it requires " - "cache.direct=on, which was not specified."); - return -EINVAL; /* No host kernel page cache */ - } -#endif #ifdef __FreeBSD__ if (S_ISCHR(st.st_mode)) { @@ -1455,6 +1443,16 @@ static void raw_refresh_zoned_limits(BlockDriverState *bs, struct stat *st, } bs->bl.zoned = zoned; + /* + * The kernel page cache does not reliably work for writes to SWR zones of + * zoned block devices because it can not guarantee the order of writes. + */ + if (!(s->open_flags & O_DIRECT)) { + error_setg(errp, "The driver supports zoned devices, and it requires " + "cache.direct=on, which was not specified."); + goto no_zoned; + } + ret = get_sysfs_long_val(st, "max_open_zones"); if (ret >= 0) { bs->bl.max_open_zones = ret; -- 2.55.0
