[PATCH 17/31] block: add a sb_open_mode helper

Christoph Hellwig
2023-06-06T07:43:16Z

Add a helper to return the open flags for blkdev_get_by* for passed in
super block flags instead of open coding the logic in many places.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/btrfs/super.c | 5 +----
fs/nilfs2/super.c | 7 ++-----
fs/super.c | 15 ++++-----------
include/linux/blkdev.h | 7 +++++++
4 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 1a2ee9407f5414..fd02b92e39106a 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1440,12 +1440,9 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
struct btrfs_fs_devices *fs_devices = NULL;
struct btrfs_fs_info *fs_info = NULL;
void *new_sec_opts = NULL;
- fmode_t mode = FMODE_READ;
+ fmode_t mode = sb_open_mode(flags);
int error = 0;

- if (!(flags & SB_RDONLY))
- mode |= FMODE_WRITE;
-
if (data) {
error = security_sb_eat_lsm_opts(data, &new_sec_opts);
if (error)
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 61d5e79a5e81df..a41fd84d4e28ab 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -1278,14 +1278,11 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
{
struct nilfs_super_data sd;
struct super_block *s;
- fmode_t mode = FMODE_READ;
struct dentry *root_dentry;
int err, s_new = false;

- if (!(flags & SB_RDONLY))
- mode |= FMODE_WRITE;
-
- sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type, NULL);
+ sd.bdev = blkdev_get_by_path(dev_name, sb_open_mode(flags), fs_type,
+ NULL);
if (IS_ERR(sd.bdev))
return ERR_CAST(sd.bdev);

diff --git a/fs/super.c b/fs/super.c
index 8563794a8bc462..dc7f328398339d 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1255,17 +1255,13 @@ int get_tree_bdev(struct fs_context *fc,
{
struct block_device *bdev;
struct super_block *s;
- fmode_t mode = FMODE_READ;
int error = 0;

- if (!(fc->sb_flags & SB_RDONLY))
- mode |= FMODE_WRITE;
-
if (!fc->source)
return invalf(fc, "No source specified");

- bdev = blkdev_get_by_path(fc->source, mode, fc->fs_type,
- &fs_holder_ops);
+ bdev = blkdev_get_by_path(fc->source, sb_open_mode(fc->sb_flags),
+ fc->fs_type, &fs_holder_ops);
if (IS_ERR(bdev)) {
errorf(fc, "%s: Can't open blockdev", fc->source);
return PTR_ERR(bdev);
@@ -1344,13 +1340,10 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
{
struct block_device *bdev;
struct super_block *s;
- fmode_t mode = FMODE_READ;
int error = 0;

- if (!(flags & SB_RDONLY))
- mode |= FMODE_WRITE;
-
- bdev = blkdev_get_by_path(dev_name, mode, fs_type, &fs_holder_ops);
+ bdev = blkdev_get_by_path(dev_name, sb_open_mode(flags), fs_type,
+ &fs_holder_ops);
if (IS_ERR(bdev))
return ERR_CAST(bdev);

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d5b99796f12c11..97803603902076 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1473,6 +1473,13 @@ struct blk_holder_ops {
void (*mark_dead)(struct block_device *bdev);
};

+/*
+ * Return the correct open flags for blkdev_get_by_* for super block flags
+ * as stored in sb->s_flags.
+ */
+#define sb_open_mode(flags) \
+ (FMODE_READ | (((flags) & SB_RDONLY) ? 0 : FMODE_WRITE))
+
struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
const struct blk_holder_ops *hops);
struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
--
2.39.2