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authorDavid Sterba <dsterba@suse.com>2019-10-07 11:11:03 +0200
committerDavid Sterba <dsterba@suse.com>2019-11-18 17:51:43 +0100
commitf7cea56c0fff95bd5a6cd21b9fa299f66193b604 (patch)
treee59752010527d9314d500aec9542f17c98279092
parent3831bf0094abed51e71cbeca8b6edf8b88c2644b (diff)
btrfs: sysfs: export supported checksums
Export supported checksum algorithms via sysfs in the list of static features: /sys/fs/btrfs/features/supported_checksums Space spearated list of checksum algorithm names. Co-developed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/ctree.c5
-rw-r--r--fs/btrfs/ctree.h2
-rw-r--r--fs/btrfs/sysfs.c22
3 files changed, 29 insertions, 0 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index bd6ea433ed65..c1561097e5a3 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -53,6 +53,11 @@ const char *btrfs_super_csum_name(u16 csum_type)
return btrfs_csums[csum_type].name;
}
+size_t __const btrfs_get_num_csums(void)
+{
+ return ARRAY_SIZE(btrfs_csums);
+}
+
struct btrfs_path *btrfs_alloc_path(void)
{
return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d5c9fbe32c0c..b17944995e09 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2163,6 +2163,8 @@ BTRFS_SETGET_STACK_FUNCS(super_uuid_tree_generation, struct btrfs_super_block,
int btrfs_super_csum_size(const struct btrfs_super_block *s);
const char *btrfs_super_csum_name(u16 csum_type);
+size_t __const btrfs_get_num_csums(void);
+
/*
* The leaf data grows from end-to-front in the node.
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index f6d3c80f2e28..41eb6a313bf8 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -295,8 +295,30 @@ static ssize_t rmdir_subvol_show(struct kobject *kobj,
}
BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
+static ssize_t supported_checksums_show(struct kobject *kobj,
+ struct kobj_attribute *a, char *buf)
+{
+ ssize_t ret = 0;
+ int i;
+
+ for (i = 0; i < btrfs_get_num_csums(); i++) {
+ /*
+ * This "trick" only works as long as 'enum btrfs_csum_type' has
+ * no holes in it
+ */
+ ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
+ (i == 0 ? "" : " "), btrfs_super_csum_name(i));
+
+ }
+
+ ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n");
+ return ret;
+}
+BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);
+
static struct attribute *btrfs_supported_static_feature_attrs[] = {
BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
+ BTRFS_ATTR_PTR(static_feature, supported_checksums),
NULL
};