@@ -21,6 +21,7 @@
#include "space-info.h"
#include "block-group.h"
#include "qgroup.h"
+#include "misc.h"
/*
* Structure name Path
@@ -92,6 +93,7 @@ static struct btrfs_feature_attr btrfs_attr_features_##_name = { \
static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
+static inline struct kobject *get_btrfs_kobj(struct kobject *kobj);
static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
{
@@ -708,6 +710,81 @@ static ssize_t btrfs_space_info_show_##field(struct kobject *kobj, \
} \
BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
+/*
+ * Return space info chunk size.
+ */
+static ssize_t btrfs_chunk_size_show(struct kobject *kobj,
+ struct kobj_attribute *a, char *buf)
+{
+ struct btrfs_space_info *sinfo = to_space_info(kobj);
+
+ return sysfs_emit(buf, "%llu\n", atomic64_read(&sinfo->chunk_size));
+}
+
+/*
+ * Store new user supplied chunk size in space info.
+ *
+ * Note: If the new chunk size value is larger than 10% of free space it is
+ * reduced to match that limit.
+ */
+static ssize_t btrfs_chunk_size_store(struct kobject *kobj,
+ struct kobj_attribute *a,
+ const char *buf, size_t len)
+{
+ struct btrfs_space_info *space_info = to_space_info(kobj);
+ struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
+ u64 val;
+ int ret;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (!fs_info) {
+ pr_err("couldn't get fs_info\n");
+ return -EPERM;
+ }
+
+ if (sb_rdonly(fs_info->sb))
+ return -EROFS;
+
+ if (!fs_info->fs_devices)
+ return -EINVAL;
+
+ if (btrfs_is_zoned(fs_info))
+ return -EINVAL;
+
+ if (!space_info) {
+ btrfs_err(fs_info, "couldn't get space_info\n");
+ return -EPERM;
+ }
+
+ /* System block type must not be changed. */
+ if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
+ return -EINVAL;
+
+ ret = kstrtoull(buf, 10, &val);
+ if (ret)
+ return ret;
+
+ val = min(val, BTRFS_MAX_DATA_CHUNK_SIZE);
+
+ /*
+ * Limit stripe size to 10% of available space.
+ */
+ val = min(div_factor(fs_info->fs_devices->total_rw_bytes, 1), val);
+
+ /* Must be multiple of 256M. */
+ val &= ~(SZ_256M - 1);
+
+ /* Must be at least 256M. */
+ if (val < SZ_256M)
+ return -EINVAL;
+
+ btrfs_update_space_info_chunk_size(space_info, val);
+
+ return val;
+}
+
SPACE_INFO_ATTR(flags);
SPACE_INFO_ATTR(total_bytes);
SPACE_INFO_ATTR(bytes_used);
@@ -718,6 +795,8 @@ SPACE_INFO_ATTR(bytes_readonly);
SPACE_INFO_ATTR(bytes_zone_unusable);
SPACE_INFO_ATTR(disk_used);
SPACE_INFO_ATTR(disk_total);
+BTRFS_ATTR_RW(space_info, chunk_size, btrfs_chunk_size_show,
+ btrfs_chunk_size_store);
/*
* Allocation information about block group types.
@@ -735,6 +814,7 @@ static struct attribute *space_info_attrs[] = {
BTRFS_ATTR_PTR(space_info, bytes_zone_unusable),
BTRFS_ATTR_PTR(space_info, disk_used),
BTRFS_ATTR_PTR(space_info, disk_total),
+ BTRFS_ATTR_PTR(space_info, chunk_size),
NULL,
};
ATTRIBUTE_GROUPS(space_info);
@@ -1099,6 +1179,20 @@ static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
return to_fs_devs(kobj)->fs_info;
}
+/*
+ * Get btrfs sysfs kobject.
+ */
+static inline struct kobject *get_btrfs_kobj(struct kobject *kobj)
+{
+ while (kobj) {
+ if (kobj->ktype == &btrfs_ktype)
+ return kobj;
+ kobj = kobj->parent;
+ }
+
+ return NULL;
+}
+
#define NUM_FEATURE_BITS 64
#define BTRFS_FEATURE_NAME_MAX 13
static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
This adds a new sysfs entry in /sys/fs/btrfs/<uuid>/allocation/<block type>/chunk_size. This allows to query the chunk size and also set the chunk size. Signed-off-by: Stefan Roesch <shr@fb.com> --- fs/btrfs/sysfs.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+)