btrfs: publish unknown feature bits in sysfs (79da4fa4) · Commits · 戴 / test

fs/btrfs/sysfs.c

+107 −1

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@
		#include <linux/completion.h>
		#include <linux/buffer_head.h>
		#include <linux/kobject.h>
		#include <linux/bug.h>

		#include "ctree.h"
		#include "disk-io.h"
		@@ -131,6 +132,101 @@ void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
		wait_for_completion(&fs_info->kobj_unregister);
		}

		const char * const btrfs_feature_set_names[3] = {
		[FEAT_COMPAT] = "compat",
		[FEAT_COMPAT_RO] = "compat_ro",
		[FEAT_INCOMPAT] = "incompat",
		};

		#define NUM_FEATURE_BITS 64
		static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
		static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];

		static void init_feature_attrs(void)
		{
		struct btrfs_feature_attr *fa;
		int set, i;

		BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
		ARRAY_SIZE(btrfs_feature_attrs));
		BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
		ARRAY_SIZE(btrfs_feature_attrs[0]));

		for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
		struct btrfs_feature_attr *sfa;
		struct attribute *a = btrfs_supported_feature_attrs[i];
		sfa = attr_to_btrfs_feature_attr(a);
		fa = &btrfs_feature_attrs[sfa->feature_set][sfa->feature_bit];

		fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
		}

		for (set = 0; set < FEAT_MAX; set++) {
		for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
		char *name = btrfs_unknown_feature_names[set][i];
		fa = &btrfs_feature_attrs[set][i];

		if (fa->kobj_attr.attr.name)
		continue;

		snprintf(name, 13, "%s:%u",
		btrfs_feature_set_names[set], i);

		fa->kobj_attr.attr.name = name;
		fa->kobj_attr.attr.mode = S_IRUGO;
		fa->feature_set = set;
		fa->feature_bit = 1ULL << i;
		}
		}
		}

		static u64 supported_feature_masks[3] = {
		[FEAT_COMPAT] = BTRFS_FEATURE_COMPAT_SUPP,
		[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
		[FEAT_INCOMPAT] = BTRFS_FEATURE_INCOMPAT_SUPP,
		};

		static int add_unknown_feature_attrs(struct btrfs_fs_info *fs_info)
		{
		int set;

		for (set = 0; set < FEAT_MAX; set++) {
		int i, count, ret, index = 0;
		struct attribute **attrs;
		struct attribute_group agroup = {
		.name = "features",
		};
		u64 features = get_features(fs_info, set);
		features &= ~supported_feature_masks[set];

		count = hweight64(features);

		if (!count)
		continue;

		attrs = kcalloc(count + 1, sizeof(void *), GFP_KERNEL);

		for (i = 0; i < NUM_FEATURE_BITS; i++) {
		struct btrfs_feature_attr *fa;

		if (!(features & (1ULL << i)))
		continue;

		fa = &btrfs_feature_attrs[set][i];
		attrs[index++] = &fa->kobj_attr.attr;
		}

		attrs[index] = NULL;
		agroup.attrs = attrs;

		ret = sysfs_merge_group(&fs_info->super_kobj, &agroup);
		kfree(attrs);
		if (ret)
		return ret;
		}
		return 0;
		}

		/* /sys/fs/btrfs/ entry */
		static struct kset *btrfs_kset;

		@@ -146,6 +242,14 @@ int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
		error = sysfs_create_group(&fs_info->super_kobj,
		&btrfs_feature_attr_group);
		if (error)
		goto failure;

		error = add_unknown_feature_attrs(fs_info);
		if (error)
		goto failure;

		return 0;
		failure:
		btrfs_sysfs_remove_one(fs_info);
		return error;
		}
		@@ -157,6 +261,8 @@ int btrfs_init_sysfs(void)
		if (!btrfs_kset)
		return -ENOMEM;

		init_feature_attrs();

		ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
		if (ret) {
		kset_unregister(btrfs_kset);

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