[PATCH v3 3/4] btrfs: add force_chunk_alloc sysfs entry to force allocation
From: Stefan Roesch <hidden>
Date: 2021-10-29 18:28:35
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
This adds the force_chunk_alloc sysfs entry to be able to force a storage allocation. This is a debugging and test feature and is enabled with the CONFIG_BTRFS_DEBUG configuration option. It is stored at /sys/fs/btrfs/<uuid>/allocation/<block_type>/force_chunk_alloc. --- fs/btrfs/sysfs.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+)
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 3b0bcbc2ed2e..983c53b76aa6 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c@@ -771,6 +771,64 @@ static ssize_t btrfs_chunk_size_store(struct kobject *kobj, return val; } +#ifdef CONFIG_BTRFS_DEBUG +/* + * Return if space info force allocation chunk flag is set. + */ +static ssize_t btrfs_force_chunk_alloc_show(struct kobject *kobj, + struct kobj_attribute *a, + char *buf) +{ + return snprintf(buf, PAGE_SIZE, "0\n"); +} + +/* + * Request chunk allocation with current chunk size. + */ +static ssize_t btrfs_force_chunk_alloc_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)); + struct btrfs_trans_handle *trans; + unsigned long val; + int ret; + + if (!fs_info) { + pr_err("couldn't get fs_info\n"); + return -EPERM; + } + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (sb_rdonly(fs_info->sb)) + return -EROFS; + + ret = kstrtoul(buf, 10, &val); + if (ret) + return ret; + + if (val == 0) + return -EINVAL; + + /* + * Allocate new chunk. + */ + trans = btrfs_start_transaction(fs_info->extent_root, 0); + if (!trans) + return PTR_ERR(trans); + ret = btrfs_force_chunk_alloc(trans, space_info->flags); + btrfs_end_transaction(trans); + + if (ret == 1) + return len; + + return -ENOSPC; +} +#endif + SPACE_INFO_ATTR(flags); SPACE_INFO_ATTR(total_bytes); SPACE_INFO_ATTR(bytes_used);
@@ -783,6 +841,10 @@ 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); +#ifdef CONFIG_BTRFS_DEBUG +BTRFS_ATTR_RW(space_info, force_chunk_alloc, btrfs_force_chunk_alloc_show, + btrfs_force_chunk_alloc_store); +#endif /* * Allocation information about block group types.
@@ -801,6 +863,9 @@ static struct attribute *space_info_attrs[] = { BTRFS_ATTR_PTR(space_info, disk_used), BTRFS_ATTR_PTR(space_info, disk_total), BTRFS_ATTR_PTR(space_info, chunk_size), +#ifdef CONFIG_BTRFS_DEBUG + BTRFS_ATTR_PTR(space_info, force_chunk_alloc), +#endif NULL, }; ATTRIBUTE_GROUPS(space_info);
--
2.30.2