[PATCH 15/31] btrfs: don't pass a holder for non-exclusive blkdev_get_by_path

Christoph Hellwig
2023-06-06T07:42:38Z

Passing a holder to blkdev_get_by_path when FMODE_EXCL isn't set doesn't
make sense, so pass NULL instead and remove the holder argument from the
call chains the only end up in non-FMODE_EXCL blkdev_get_by_path calls.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/btrfs/super.c | 16 ++++++----------
fs/btrfs/volumes.c | 17 ++++++++---------
fs/btrfs/volumes.h | 3 +--
3 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index ec18e22106023b..1a2ee9407f5414 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -849,8 +849,7 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
* All other options will be parsed on much later in the mount process and
* only when we need to allocate a new super block.
*/
-static int btrfs_parse_device_options(const char *options, fmode_t flags,
- void *holder)
+static int btrfs_parse_device_options(const char *options, fmode_t flags)
{
substring_t args[MAX_OPT_ARGS];
char *device_name, *opts, *orig, *p;
@@ -884,8 +883,7 @@ static int btrfs_parse_device_options(const char *options, fmode_t flags,
error = -ENOMEM;
goto out;
}
- device = btrfs_scan_one_device(device_name, flags,
- holder);
+ device = btrfs_scan_one_device(device_name, flags);
kfree(device_name);
if (IS_ERR(device)) {
error = PTR_ERR(device);
@@ -1477,13 +1475,13 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
}

mutex_lock(&uuid_mutex);
- error = btrfs_parse_device_options(data, mode, fs_type);
+ error = btrfs_parse_device_options(data, mode);
if (error) {
mutex_unlock(&uuid_mutex);
goto error_fs_info;
}

- device = btrfs_scan_one_device(device_name, mode, fs_type);
+ device = btrfs_scan_one_device(device_name, mode);
if (IS_ERR(device)) {
mutex_unlock(&uuid_mutex);
error = PTR_ERR(device);
@@ -2190,8 +2188,7 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
switch (cmd) {
case BTRFS_IOC_SCAN_DEV:
mutex_lock(&uuid_mutex);
- device = btrfs_scan_one_device(vol->name, FMODE_READ,
- &btrfs_root_fs_type);
+ device = btrfs_scan_one_device(vol->name, FMODE_READ);
ret = PTR_ERR_OR_ZERO(device);
mutex_unlock(&uuid_mutex);
break;
@@ -2205,8 +2202,7 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
break;
case BTRFS_IOC_DEVICES_READY:
mutex_lock(&uuid_mutex);
- device = btrfs_scan_one_device(vol->name, FMODE_READ,
- &btrfs_root_fs_type);
+ device = btrfs_scan_one_device(vol->name, FMODE_READ);
if (IS_ERR(device)) {
mutex_unlock(&uuid_mutex);
ret = PTR_ERR(device);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 784ccc8f6c69c1..035868cee3ddc3 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1348,8 +1348,7 @@ int btrfs_forget_devices(dev_t devt)
* and we are not allowed to call set_blocksize during the scan. The superblock
* is read via pagecache
*/
-struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
- void *holder)
+struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags)
{
struct btrfs_super_block *disk_super;
bool new_device_added = false;
@@ -1368,16 +1367,16 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
*/

/*
- * Avoid using flag |= FMODE_EXCL here, as the systemd-udev may
- * initiate the device scan which may race with the user's mount
- * or mkfs command, resulting in failure.
- * Since the device scan is solely for reading purposes, there is
- * no need for FMODE_EXCL. Additionally, the devices are read again
+ * Avoid an exclusive open here, as the systemd-udev may initiate the
+ * device scan which may race with the user's mount or mkfs command,
+ * resulting in failure.
+ * Since the device scan is solely for reading purposes, there is no
+ * need for an exclusive open. Additionally, the devices are read again
* during the mount process. It is ok to get some inconsistent
* values temporarily, as the device paths of the fsid are the only
* required information for assembling the volume.
*/
- bdev = blkdev_get_by_path(path, flags, holder, NULL);
+ bdev = blkdev_get_by_path(path, flags, NULL, NULL);
if (IS_ERR(bdev))
return ERR_CAST(bdev);

@@ -2381,7 +2380,7 @@ int btrfs_get_dev_args_from_path(struct btrfs_fs_info *fs_info,
return -ENOMEM;
}

- ret = btrfs_get_bdev_and_sb(path, FMODE_READ, fs_info->bdev_holder, 0,
+ ret = btrfs_get_bdev_and_sb(path, FMODE_READ, NULL, 0,
&bdev, &disk_super);
if (ret) {
btrfs_put_dev_args_from_path(args);
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index bf47a1a70813ba..eb97a397b3c3fb 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -600,8 +600,7 @@ struct btrfs_block_group *btrfs_create_chunk(struct btrfs_trans_handle *trans,
void btrfs_mapping_tree_free(struct extent_map_tree *tree);
int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
fmode_t flags, void *holder);
-struct btrfs_device *btrfs_scan_one_device(const char *path,
- fmode_t flags, void *holder);
+struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags);
int btrfs_forget_devices(dev_t devt);
void btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices);
--
2.39.2