diff options
| author | Christian Schoenebeck <qemu_oss@crudebyte.com> | 2021-09-22 15:13:31 +0200 |
|---|---|---|
| committer | Christian Schoenebeck <qemu_oss@crudebyte.com> | 2021-10-27 14:45:22 +0200 |
| commit | 669ced09b3b6070d478acce51810591b78ab0ccd (patch) | |
| tree | 42dc8961696cfca1bf96b5ea638d0db0f78c6725 /hw/9pfs | |
| parent | 931ce30859176f0f7daac6bac255dae5eb21284e (diff) | |
9pfs: fix wrong I/O block size in Rgetattr
When client sent a 9p Tgetattr request then the wrong I/O block
size value was returned by 9p server; instead of host file
system's I/O block size it should rather return an I/O block
size according to 9p session's 'msize' value, because the value
returned to client should be an "optimum" block size for I/O
(i.e. to maximize performance), it should not reflect the actual
physical block size of the underlying storage media.
The I/O block size of a host filesystem is typically 4k, so the
value returned was far too low for good 9p I/O performance.
This patch adds stat_to_iounit() with a similar approach as the
existing get_iounit() function.
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <E1mT2Js-0000DW-OH@lizzy.crudebyte.com>
Diffstat (limited to 'hw/9pfs')
| -rw-r--r-- | hw/9pfs/9p.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index c857b31321..708b030474 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -1262,6 +1262,25 @@ static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu, V9fsPath *path, #define P9_STATS_ALL 0x00003fffULL /* Mask for All fields above */ +static int32_t stat_to_iounit(const V9fsPDU *pdu, const struct stat *stbuf) +{ + int32_t iounit = 0; + V9fsState *s = pdu->s; + + /* + * iounit should be multiples of st_blksize (host filesystem block size) + * as well as less than (client msize - P9_IOHDRSZ) + */ + if (stbuf->st_blksize) { + iounit = stbuf->st_blksize; + iounit *= (s->msize - P9_IOHDRSZ) / stbuf->st_blksize; + } + if (!iounit) { + iounit = s->msize - P9_IOHDRSZ; + } + return iounit; +} + static int stat_to_v9stat_dotl(V9fsPDU *pdu, const struct stat *stbuf, V9fsStatDotl *v9lstat) { @@ -1273,7 +1292,7 @@ static int stat_to_v9stat_dotl(V9fsPDU *pdu, const struct stat *stbuf, v9lstat->st_gid = stbuf->st_gid; v9lstat->st_rdev = stbuf->st_rdev; v9lstat->st_size = stbuf->st_size; - v9lstat->st_blksize = stbuf->st_blksize; + v9lstat->st_blksize = stat_to_iounit(pdu, stbuf); v9lstat->st_blocks = stbuf->st_blocks; v9lstat->st_atime_sec = stbuf->st_atime; v9lstat->st_atime_nsec = stbuf->st_atim.tv_nsec; |