Use the new vfs API sb_want_write() to do the write protection of the label change transaction.
Signed-off-by: Qu Wenruo <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
