Use the new vfs API sb_want_write() to do the write protection of the
label change transaction.
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
v4:
Newly introduced.
v5:
Change to use sb_want_write().
---
fs/btrfs/sysfs.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index b2e7bb4..3218245 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -25,6 +25,7 @@
#include <linux/bug.h>
#include <linux/genhd.h>
#include <linux/debugfs.h>
+#include <linux/mount.h>
#include "ctree.h"
#include "disk-io.h"
@@ -377,8 +378,6 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
int ret;
size_t p_len;
- if (fs_info->sb->s_flags & MS_RDONLY)
- return -EROFS;
/*
* p_len is the len until the first occurrence of either
@@ -389,9 +388,15 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
if (p_len >= BTRFS_LABEL_SIZE)
return -EINVAL;
+ ret = sb_want_write(fs_info->sb);
+ if (ret)
+ return ret;
+
trans = btrfs_start_transaction(root, 0);
- if (IS_ERR(trans))
- return PTR_ERR(trans);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out;
+ }
spin_lock(&root->fs_info->super_lock);
memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
@@ -399,9 +404,10 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
spin_unlock(&root->fs_info->super_lock);
ret = btrfs_commit_transaction(trans, root);
+out:
+ sb_drop_write(fs_info->sb);
if (!ret)
return len;
-
return ret;
}
BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);
--
2.2.2
--
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