Re: [RFC v3 3/5] file-posix: introduce get_sysfs_long_val for zoned device information.

[Sam Li]

Hannes Reinecke <hare@suse.de> 于2022年6月27日周一 15:31写道：
>
> On 6/27/22 02:19, Sam Li wrote:
> > Use sysfs attribute files to get the zoned device information in case
> > that ioctl() commands of zone management interface won't work. It can
> > return long type of value like chunk_sectors, zoned_append_max_bytes,
> > max_open_zones, max_active_zones.
> > ---
> >   block/file-posix.c | 37 +++++++++++++++++++++++++------------
> >   1 file changed, 25 insertions(+), 12 deletions(-)
> >
> > diff --git a/block/file-posix.c b/block/file-posix.c
> > index 1b8b0d351f..73c2cdfbca 100644
> > --- a/block/file-posix.c
> > +++ b/block/file-posix.c
> > @@ -1216,15 +1216,19 @@ static int hdev_get_max_hw_transfer(int fd, struct 
> > stat *st)
> >   #endif
> >   }
> >
> > -static int hdev_get_max_segments(int fd, struct stat *st)
> > -{
> > +/*
> > + * Get zoned device information (chunk_sectors, zoned_append_max_bytes,
> > + * max_open_zones, max_active_zones) through sysfs attribute files.
> > + */
> > +static long get_sysfs_long_val(int fd, struct stat *st,
> > +                               const char *attribute) {
> >   #ifdef CONFIG_LINUX
> >       char buf[32];
> >       const char *end;
> >       char *sysfspath = NULL;
> >       int ret;
> >       int sysfd = -1;
> > -    long max_segments;
> > +    long val;
> >
> >       if (S_ISCHR(st->st_mode)) {
> >           if (ioctl(fd, SG_GET_SG_TABLESIZE, &ret) == 0) {
> > @@ -1237,8 +1241,9 @@ static int hdev_get_max_segments(int fd, struct stat 
> > *st)
> >           return -ENOTSUP;
> >       }
> >
> > -    sysfspath = g_strdup_printf("/sys/dev/block/%u:%u/queue/max_segments",
> > -                                major(st->st_rdev), minor(st->st_rdev));
> > +    sysfspath = g_strdup_printf("/sys/dev/block/%u:%u/queue/%s",
> > +                                major(st->st_rdev), minor(st->st_rdev),
> > +                                attribute);
> >       sysfd = open(sysfspath, O_RDONLY);
> >       if (sysfd == -1) {
> >           ret = -errno;
> > @@ -1256,9 +1261,9 @@ static int hdev_get_max_segments(int fd, struct stat 
> > *st)
> >       }
> >       buf[ret] = 0;
> >       /* The file is ended with '\n', pass 'end' to accept that. */
> > -    ret = qemu_strtol(buf, &end, 10, &max_segments);
> > +    ret = qemu_strtol(buf, &end, 10, &val);
> >       if (ret == 0 && end && *end == '\n') {
> > -        ret = max_segments;
> > +        ret = val;
> >       }
> >
> >   out:
> > @@ -1272,6 +1277,15 @@ out:
> >   #endif
> >   }
> >
> > +static int hdev_get_max_segments(int fd, struct stat *st) {
> > +    int ret;
> > +    ret = get_sysfs_long_val(fd, st, "max_segments");
> > +    if (ret < 0) {
> > +        return -1;
> > +    }
> > +    return ret;
> > +}
> > +
> >   static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
> >   {
> >       BDRVRawState *s = bs->opaque;
> > @@ -1872,6 +1886,7 @@ static int handle_aiocb_zone_report(void *opaque) {
> >
> >   static int handle_aiocb_zone_mgmt(void *opaque) {
> >       RawPosixAIOData *aiocb = opaque;
> > +    BlockDriverState *s = aiocb->bs;
> >       int fd = aiocb->aio_fildes;
> >       int64_t offset = aiocb->aio_offset;
> >       int64_t len = aiocb->aio_nbytes;
> > @@ -1884,11 +1899,9 @@ static int handle_aiocb_zone_mgmt(void *opaque) {
> >       int64_t zone_size_mask;
> >       int ret;
> >
> > -    ret = ioctl(fd, BLKGETZONESZ, &zone_size);
> > -    if (ret) {
> > -        return -1;
> > -    }
> > -
> > +    g_autofree struct stat *file = g_new(struct stat, 1);
> > +    stat(s->filename, file);
> > +    zone_size = get_sysfs_long_val(fd, file, "chunk_sectors");
> >       zone_size_mask = zone_size - 1;
> >       if (offset & zone_size_mask) {
> >           error_report("offset is not the start of a zone");
>
> Round of applause.
>
Thanks! It was based on Damien's suggestion.

> Reviewed-by: Hannes Reinecke <hare@suse.de>
>
> Cheers,
>
> Hannes
> --
> Dr. Hannes Reinecke                        Kernel Storage Architect
> hare@suse.de                                      +49 911 74053 688
> SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
> HRB 36809 (AG Nürnberg), GF: Felix Imendörffer