btrfs: use proper endianness accessors for super_copy

asj · kdave · commit 3c181c12c431 · 2018-03-01T16:17:27.000+01:00
The fs_info::super_copy is a byte copy of the on-disk structure and all members must use the accessor macros/functions to obtain the right value. This was missing in update_super_roots and in sysfs readers. Moving between opposite endianness hosts will report bogus numbers in sysfs, and mount may fail as the root will not be restored correctly. If the filesystem is always used on a same endian host, this will not be a problem. Fix this by using the btrfs_set_super...() functions to set fs_info::super_copy values, and for the sysfs, use the cached fs_info::nodesize/sectorsize values. CC: stable@vger.kernel.org Fixes: df93589 ("btrfs: export more from FS_INFO to sysfs") Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
@@ -423,7 +423,7 @@ static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
+	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->nodesize);
 }
 
 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
@@ -433,8 +433,7 @@ static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n",
-			fs_info->super_copy->sectorsize);
+	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->sectorsize);
 }
 
 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
@@ -444,8 +443,7 @@ static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n",
-			fs_info->super_copy->sectorsize);
+	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->sectorsize);
 }
 
 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
@@ -1722,19 +1722,23 @@ static void update_super_roots(struct btrfs_fs_info *fs_info)
 
 	super = fs_info->super_copy;
 
+	/* update latest btrfs_super_block::chunk_root refs */
 	root_item = &fs_info->chunk_root->root_item;
-	super->chunk_root = root_item->bytenr;
-	super->chunk_root_generation = root_item->generation;
-	super->chunk_root_level = root_item->level;
+	btrfs_set_super_chunk_root(super, root_item->bytenr);
+	btrfs_set_super_chunk_root_generation(super, root_item->generation);
+	btrfs_set_super_chunk_root_level(super, root_item->level);
 
+	/* update latest btrfs_super_block::root refs */
 	root_item = &fs_info->tree_root->root_item;
-	super->root = root_item->bytenr;
-	super->generation = root_item->generation;
-	super->root_level = root_item->level;
+	btrfs_set_super_root(super, root_item->bytenr);
+	btrfs_set_super_generation(super, root_item->generation);
+	btrfs_set_super_root_level(super, root_item->level);
+
 	if (btrfs_test_opt(fs_info, SPACE_CACHE))
-		super->cache_generation = root_item->generation;
+		btrfs_set_super_cache_generation(super, root_item->generation);
 	if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
-		super->uuid_tree_generation = root_item->generation;
+		btrfs_set_super_uuid_tree_generation(super,
+						     root_item->generation);
 }
 
 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)

Original file line number	Diff line number	Diff line change
`@@ -423,7 +423,7 @@ static ssize_t btrfs_nodesize_show(struct kobject *kobj,`
`423`	`423`	`{`
`424`	`424`	`struct btrfs_fs_info *fs_info = to_fs_info(kobj);`
`425`	`425`
`426`		`- return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);`
	`426`	`+ return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->nodesize);`
`427`	`427`	`}`
`428`	`428`
`429`	`429`	`BTRFS_ATTR(, nodesize, btrfs_nodesize_show);`
`@@ -433,8 +433,7 @@ static ssize_t btrfs_sectorsize_show(struct kobject *kobj,`
`433`	`433`	`{`
`434`	`434`	`struct btrfs_fs_info *fs_info = to_fs_info(kobj);`
`435`	`435`
`436`		`- return snprintf(buf, PAGE_SIZE, "%u\n",`
`437`		`- fs_info->super_copy->sectorsize);`
	`436`	`+ return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->sectorsize);`
`438`	`437`	`}`
`439`	`438`
`440`	`439`	`BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);`
`@@ -444,8 +443,7 @@ static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,`
`444`	`443`	`{`
`445`	`444`	`struct btrfs_fs_info *fs_info = to_fs_info(kobj);`
`446`	`445`
`447`		`- return snprintf(buf, PAGE_SIZE, "%u\n",`
`448`		`- fs_info->super_copy->sectorsize);`
	`446`	`+ return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->sectorsize);`
`449`	`447`	`}`
`450`	`448`
`451`	`449`	`BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);`