From: Yu Kuai <yukuai3@xxxxxxxxxx>
So that iomap and bffer_head can convert to use bdev_file in following
patches.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
block/bdev.c | 137 +++++++++++++++++++++++++++++---------
include/linux/blk_types.h | 1 +
2 files changed, 107 insertions(+), 31 deletions(-)
diff --git a/block/bdev.c b/block/bdev.c
index 86db97b0709e..3d300823da6b 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -846,6 +846,101 @@ static void init_bdev_file(struct file *bdev_file, struct block_device *bdev,
bdev_file->private_data = holder;
}
+/*
+ * If BLK_OPEN_WRITE_IOCTL is set then this is a historical quirk
+ * associated with the floppy driver where it has allowed ioctls if the
+ * file was opened for writing, but does not allow reads or writes.
+ * Make sure that this quirk is reflected in @f_flags.
+ *
+ * It can also happen if a block device is opened as O_RDWR | O_WRONLY.
+ */
+static unsigned blk_to_file_flags(blk_mode_t mode)
+{
+ unsigned int flags = 0;
+
+ if ((mode & (BLK_OPEN_READ | BLK_OPEN_WRITE)) ==
+ (BLK_OPEN_READ | BLK_OPEN_WRITE))
+ flags |= O_RDWR;
+ else if (mode & BLK_OPEN_WRITE_IOCTL)
+ flags |= O_RDWR | O_WRONLY;
+ else if (mode & BLK_OPEN_WRITE)
+ flags |= O_WRONLY;
+ else if (mode & BLK_OPEN_READ)
+ flags |= O_RDONLY; /* homeopathic, because O_RDONLY is 0 */
+ else
+ WARN_ON_ONCE(true);
+
+ if (mode & BLK_OPEN_NDELAY)
+ flags |= O_NDELAY;
+
+ return flags;
+}
+
+static int __stash_bdev_file(struct block_device *bdev)
+{
+ struct inode *inode = bdev_inode(bdev);
+ unsigned int flags = blk_to_file_flags(BLK_OPEN_READ | BLK_OPEN_WRITE);
+ struct file *file;
+ static struct file_operations stash_fops;
+
+ file = inode->i_private;
+ if (!file) {
+ /*
+ * This file is used for iomap/buffer_head for raw block_device
+ * read/write operations to access block_device.
+ */
+ file = alloc_file_pseudo_noaccount(bdev_inode(bdev),
+ blockdev_mnt, "", flags | O_LARGEFILE,
+ &stash_fops);
+
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+
+ ihold(inode);
+ init_bdev_file(file, bdev, 0, NULL);
+
+ inode->i_private = file;
+ WARN_ON_ONCE(bdev->stash_count != 0);
+ }
+
+ bdev->stash_count++;
+ return 0;
+}
+
+static void __unstash_bdev_file(struct block_device *bdev)
+{
+
+ WARN_ON_ONCE(bdev->stash_count <= 0);
+ if (--bdev->stash_count == 0) {
+ struct inode *inode = bdev_inode(bdev);
+ struct file *file = inode->i_private;
+
+ inode->i_private = NULL;
+ fput(file);
+ }
+}
+
+static int stash_bdev_file(struct block_device *bdev)
+{
+ int ret = __stash_bdev_file(bdev);
+
+ if (ret || !bdev_is_partition(bdev))
+ return ret;
+
+ ret = __stash_bdev_file(bdev_whole(bdev));
+ if (ret)
+ __unstash_bdev_file(bdev);
+
+ return ret;
+}
+
+static void unstash_bdev_file(struct block_device *bdev)
+{
+ __unstash_bdev_file(bdev);
+ if (bdev_is_partition(bdev))
+ __unstash_bdev_file(bdev_whole(bdev));
+}
+
/**
* bdev_open - open a block device
* @bdev: block device to open
@@ -891,12 +986,17 @@ int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
ret = -EBUSY;
if (!bdev_may_open(bdev, mode))
goto put_module;
+
+ ret = stash_bdev_file(bdev);
+ if (ret)
+ goto put_module;
+
if (bdev_is_partition(bdev))
ret = blkdev_get_part(bdev, mode);
else
ret = blkdev_get_whole(bdev, mode);
if (ret)
- goto put_module;
+ goto unstash_bdev_file;
bdev_claim_write_access(bdev, mode);
if (holder) {
bd_finish_claiming(bdev, holder, hops);
@@ -922,6 +1022,9 @@ int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
init_bdev_file(bdev_file, bdev, mode, holder);
return 0;
+
+unstash_bdev_file:
+ unstash_bdev_file(bdev);
put_module:
module_put(disk->fops->owner);
abort_claiming:
@@ -932,36 +1035,6 @@ int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
return ret;
}
-/*
- * If BLK_OPEN_WRITE_IOCTL is set then this is a historical quirk
- * associated with the floppy driver where it has allowed ioctls if the
- * file was opened for writing, but does not allow reads or writes.
- * Make sure that this quirk is reflected in @f_flags.
- *
- * It can also happen if a block device is opened as O_RDWR | O_WRONLY.
- */
-static unsigned blk_to_file_flags(blk_mode_t mode)
-{
- unsigned int flags = 0;
-
- if ((mode & (BLK_OPEN_READ | BLK_OPEN_WRITE)) ==
- (BLK_OPEN_READ | BLK_OPEN_WRITE))
- flags |= O_RDWR;
- else if (mode & BLK_OPEN_WRITE_IOCTL)
- flags |= O_RDWR | O_WRONLY;
- else if (mode & BLK_OPEN_WRITE)
- flags |= O_WRONLY;
- else if (mode & BLK_OPEN_READ)
- flags |= O_RDONLY; /* homeopathic, because O_RDONLY is 0 */
- else
- WARN_ON_ONCE(true);
-
- if (mode & BLK_OPEN_NDELAY)
- flags |= O_NDELAY;
-
- return flags;
-}
-
struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
const struct blk_holder_ops *hops)
{
@@ -1073,6 +1146,8 @@ void bdev_release(struct file *bdev_file)
blkdev_put_part(bdev);
else
blkdev_put_whole(bdev);
+
+ unstash_bdev_file(bdev);
mutex_unlock(&disk->open_mutex);
module_put(disk->fops->owner);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index cb1526ec44b5..22f736908cbe 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -70,6 +70,7 @@ struct block_device {
#endif
bool bd_ro_warned;
int bd_writers;
+ int stash_count;
/*
* keep this out-of-line as it's both big and not needed in the fast
* path
--
2.39.2
