| Message ID | abd366082eeb8b289cd420cb04528a687a250433.1603347462.git.anand.jain@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | readmirror feature (read_policy sysfs and in-memory only approach) | expand |
On Thu, Oct 22, 2020 at 03:43:37PM +0800, Anand Jain wrote: > Add > > /sys/fs/btrfs/UUID/read_policy > > attribute so that the read policy for the raid1, raid1c34 and raid10 can > be tuned. > > When this attribute is read, it shall show all available policies, with > active policy being with in [ ]. The read_policy attribute can be written > using one of the items listed in there. > > For example: > $cat /sys/fs/btrfs/UUID/read_policy > [pid] > $echo pid > /sys/fs/btrfs/UUID/read_policy > > Signed-off-by: Anand Jain <anand.jain@oracle.com> > --- > v9: fix C coding style, static const char* > v5: > Title rename: old: btrfs: sysfs, add read_policy attribute > Uses the btrfs_strmatch() helper (BTRFS_READ_POLICY_NAME_MAX dropped). > Use the table for the policy names. > Rename len to ret. > Use a simple logic to prefix space in btrfs_read_policy_show() > Reviewed-by: Josef Bacik <josef@toxicpanda.com> dropped. > > v4:- > v3: rename [by_pid] to [pid] > v2: v2: check input len before strip and kstrdup > > fs/btrfs/sysfs.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 49 insertions(+) > > diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c > index 5ea262d289c6..e23ae3643527 100644 > --- a/fs/btrfs/sysfs.c > +++ b/fs/btrfs/sysfs.c > @@ -883,6 +883,54 @@ static int btrfs_strmatch(const char *given, const char *golden) > return -EINVAL; > } > > +static const char * const btrfs_read_policy_name[] = { "pid" }; > + > +static ssize_t btrfs_read_policy_show(struct kobject *kobj, > + struct kobj_attribute *a, char *buf) > +{ > + int i; > + ssize_t ret = 0; > + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); > + > + for (i = 0; i < BTRFS_NR_READ_POLICY; i++) { > + if (fs_devices->read_policy == i) > + ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s[%s]", All snprintf have been upgraded to scnprintf as it does have sane behaviour when the buffer is not large enough. > + (ret == 0 ? "" : " "), > + btrfs_read_policy_name[i]); > + else > + ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s", > + (ret == 0 ? "" : " "), > + btrfs_read_policy_name[i]); > + } > + > + ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n"); > + > + return ret; > +}
On 27/10/20 1:57 am, David Sterba wrote: > On Thu, Oct 22, 2020 at 03:43:37PM +0800, Anand Jain wrote: >> Add >> >> /sys/fs/btrfs/UUID/read_policy >> >> attribute so that the read policy for the raid1, raid1c34 and raid10 can >> be tuned. >> >> When this attribute is read, it shall show all available policies, with >> active policy being with in [ ]. The read_policy attribute can be written >> using one of the items listed in there. >> >> For example: >> $cat /sys/fs/btrfs/UUID/read_policy >> [pid] >> $echo pid > /sys/fs/btrfs/UUID/read_policy >> >> Signed-off-by: Anand Jain <anand.jain@oracle.com> >> --- >> v9: fix C coding style, static const char* >> v5: >> Title rename: old: btrfs: sysfs, add read_policy attribute >> Uses the btrfs_strmatch() helper (BTRFS_READ_POLICY_NAME_MAX dropped). >> Use the table for the policy names. >> Rename len to ret. >> Use a simple logic to prefix space in btrfs_read_policy_show() >> Reviewed-by: Josef Bacik <josef@toxicpanda.com> dropped. >> >> v4:- >> v3: rename [by_pid] to [pid] >> v2: v2: check input len before strip and kstrdup >> >> fs/btrfs/sysfs.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 49 insertions(+) >> >> diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c >> index 5ea262d289c6..e23ae3643527 100644 >> --- a/fs/btrfs/sysfs.c >> +++ b/fs/btrfs/sysfs.c >> @@ -883,6 +883,54 @@ static int btrfs_strmatch(const char *given, const char *golden) >> return -EINVAL; >> } >> >> +static const char * const btrfs_read_policy_name[] = { "pid" }; >> + >> +static ssize_t btrfs_read_policy_show(struct kobject *kobj, >> + struct kobj_attribute *a, char *buf) >> +{ >> + int i; >> + ssize_t ret = 0; >> + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); >> + >> + for (i = 0; i < BTRFS_NR_READ_POLICY; i++) { >> + if (fs_devices->read_policy == i) >> + ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s[%s]", > > All snprintf have been upgraded to scnprintf as it does have sane > behaviour when the buffer is not large enough. This is taken care in v10. Thanks, Anand > >> + (ret == 0 ? "" : " "), >> + btrfs_read_policy_name[i]); >> + else >> + ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s", >> + (ret == 0 ? "" : " "), >> + btrfs_read_policy_name[i]); >> + } >> + >> + ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n"); >> + >> + return ret; >> +}
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 5ea262d289c6..e23ae3643527 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -883,6 +883,54 @@ static int btrfs_strmatch(const char *given, const char *golden) return -EINVAL; } +static const char * const btrfs_read_policy_name[] = { "pid" }; + +static ssize_t btrfs_read_policy_show(struct kobject *kobj, + struct kobj_attribute *a, char *buf) +{ + int i; + ssize_t ret = 0; + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); + + for (i = 0; i < BTRFS_NR_READ_POLICY; i++) { + if (fs_devices->read_policy == i) + ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s[%s]", + (ret == 0 ? "" : " "), + btrfs_read_policy_name[i]); + else + ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s", + (ret == 0 ? "" : " "), + btrfs_read_policy_name[i]); + } + + ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n"); + + return ret; +} + +static ssize_t btrfs_read_policy_store(struct kobject *kobj, + struct kobj_attribute *a, + const char *buf, size_t len) +{ + int i; + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); + + for (i = 0; i < BTRFS_NR_READ_POLICY; i++) { + if (btrfs_strmatch(buf, btrfs_read_policy_name[i]) == 0) { + if (i != fs_devices->read_policy) { + fs_devices->read_policy = i; + btrfs_info(fs_devices->fs_info, + "read policy set to '%s'", + btrfs_read_policy_name[i]); + } + return len; + } + } + + return -EINVAL; +} +BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store); + static const struct attribute *btrfs_attrs[] = { BTRFS_ATTR_PTR(, label), BTRFS_ATTR_PTR(, nodesize), @@ -893,6 +941,7 @@ static const struct attribute *btrfs_attrs[] = { BTRFS_ATTR_PTR(, checksum), BTRFS_ATTR_PTR(, exclusive_operation), BTRFS_ATTR_PTR(, generation), + BTRFS_ATTR_PTR(, read_policy), NULL, };