| Message ID | 20200105151402.1440-3-anand.jain@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | readmirror feature (sysfs and in-memory only approach) | expand |
On 1/5/20 10:14 AM, Anand Jain wrote: > Add > > /sys/fs/btrfs/UUID/read_policy > > attribute so that the read policy for the raid1 and raid10 chunks can be > tuned. > > When this attribute is read, it shall show all available policies, and > the active policy is with in [ ], read_policy attribute can be written > using one of the items showed in the read. > > For example: > cat /sys/fs/btrfs/UUID/read_policy > [by_pid] > echo by_pid > /sys/fs/btrfs/UUID/read_policy > echo -n by_pid > /sys/fs/btrfs/UUID/read_policy > > Signed-off-by: Anand Jain <anand.jain@oracle.com> > --- > fs/btrfs/sysfs.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++ > fs/btrfs/volumes.h | 1 + > 2 files changed, 68 insertions(+) > > diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c > index d414b98fb27f..ae2935184d75 100644 > --- a/fs/btrfs/sysfs.c > +++ b/fs/btrfs/sysfs.c > @@ -642,6 +642,72 @@ static ssize_t btrfs_checksum_show(struct kobject *kobj, > > BTRFS_ATTR(, checksum, btrfs_checksum_show); > > +static const inline char *btrfs_read_policy_name(enum btrfs_read_policy_type type) > +{ > + switch (type) { > + case BTRFS_READ_BY_PID: > + return "by_pid"; > + default: > + return "null"; > + } > +} > + > +static ssize_t btrfs_read_policy_show(struct kobject *kobj, > + struct kobj_attribute *a, char *buf) > +{ > + int i; > + ssize_t len = 0; > + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); > + > + for (i = 0; i < BTRFS_NR_READ_POLICY_TYPE; i++) { > + if (len) > + len += snprintf(buf + len, PAGE_SIZE, " "); > + if (fs_devices->read_policy == i) > + len += snprintf(buf + len, PAGE_SIZE, "[%s]", > + btrfs_read_policy_name(i)); > + else > + len += snprintf(buf + len, PAGE_SIZE, "%s", > + btrfs_read_policy_name(i)); > + } > + > + len += snprintf(buf + len, PAGE_SIZE, "\n"); > + > + return len; > +} > + > +static ssize_t btrfs_read_policy_store(struct kobject *kobj, > + struct kobj_attribute *a, > + const char *buf, size_t len) > +{ > + int i; > + char *stripped; > + char *policy_name; > + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); > + > + policy_name = kstrdup(buf, GFP_KERNEL); > + if (!policy_name) > + return -ENOMEM; > + > + stripped = strstrip(policy_name); > + if (strlen(stripped) > BTRFS_READ_POLICY_NAME_MAX) { > + kfree(policy_name); > + return -EINVAL; > + } We have the len passed to us, let's do the length check _before_ we arbitrarily kstrdup(). Thanks, Josef
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index d414b98fb27f..ae2935184d75 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -642,6 +642,72 @@ static ssize_t btrfs_checksum_show(struct kobject *kobj, BTRFS_ATTR(, checksum, btrfs_checksum_show); +static const inline char *btrfs_read_policy_name(enum btrfs_read_policy_type type) +{ + switch (type) { + case BTRFS_READ_BY_PID: + return "by_pid"; + default: + return "null"; + } +} + +static ssize_t btrfs_read_policy_show(struct kobject *kobj, + struct kobj_attribute *a, char *buf) +{ + int i; + ssize_t len = 0; + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); + + for (i = 0; i < BTRFS_NR_READ_POLICY_TYPE; i++) { + if (len) + len += snprintf(buf + len, PAGE_SIZE, " "); + if (fs_devices->read_policy == i) + len += snprintf(buf + len, PAGE_SIZE, "[%s]", + btrfs_read_policy_name(i)); + else + len += snprintf(buf + len, PAGE_SIZE, "%s", + btrfs_read_policy_name(i)); + } + + len += snprintf(buf + len, PAGE_SIZE, "\n"); + + return len; +} + +static ssize_t btrfs_read_policy_store(struct kobject *kobj, + struct kobj_attribute *a, + const char *buf, size_t len) +{ + int i; + char *stripped; + char *policy_name; + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); + + policy_name = kstrdup(buf, GFP_KERNEL); + if (!policy_name) + return -ENOMEM; + + stripped = strstrip(policy_name); + if (strlen(stripped) > BTRFS_READ_POLICY_NAME_MAX) { + kfree(policy_name); + return -EINVAL; + } + + for (i = 0; i < BTRFS_NR_READ_POLICY_TYPE; i++) { + if (strncmp(stripped, btrfs_read_policy_name(i), + strlen(stripped)) == 0) { + fs_devices->read_policy = i; + kfree(policy_name); + return len; + } + } + + kfree(policy_name); + 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), @@ -650,6 +716,7 @@ static const struct attribute *btrfs_attrs[] = { BTRFS_ATTR_PTR(, quota_override), BTRFS_ATTR_PTR(, metadata_uuid), BTRFS_ATTR_PTR(, checksum), + BTRFS_ATTR_PTR(, read_policy), NULL, }; diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 3bbf0e51433f..dd8a8d2fbbe1 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -210,6 +210,7 @@ BTRFS_DEVICE_GETSET_FUNCS(disk_total_bytes); BTRFS_DEVICE_GETSET_FUNCS(bytes_used); /* read_policy types */ +#define BTRFS_READ_POLICY_NAME_MAX 12 #define BTRFS_READ_POLICY_DEFAULT BTRFS_READ_BY_PID enum btrfs_read_policy_type { BTRFS_READ_BY_PID,
Add /sys/fs/btrfs/UUID/read_policy attribute so that the read policy for the raid1 and raid10 chunks can be tuned. When this attribute is read, it shall show all available policies, and the active policy is with in [ ], read_policy attribute can be written using one of the items showed in the read. For example: cat /sys/fs/btrfs/UUID/read_policy [by_pid] echo by_pid > /sys/fs/btrfs/UUID/read_policy echo -n by_pid > /sys/fs/btrfs/UUID/read_policy Signed-off-by: Anand Jain <anand.jain@oracle.com> --- fs/btrfs/sysfs.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++ fs/btrfs/volumes.h | 1 + 2 files changed, 68 insertions(+)