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-rw-r--r--fs/block_dev.c62
1 files changed, 60 insertions, 2 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 38e721b..cdfb625 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -116,6 +116,8 @@ EXPORT_SYMBOL(invalidate_bdev);
int set_blocksize(struct block_device *bdev, int size)
{
+ struct address_space *mapping;
+
/* Size must be a power of two, and between 512 and PAGE_SIZE */
if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
return -EINVAL;
@@ -124,6 +126,20 @@ int set_blocksize(struct block_device *bdev, int size)
if (size < bdev_logical_block_size(bdev))
return -EINVAL;
+ /* Prevent starting I/O or mapping the device */
+ down_write(&bdev->bd_block_size_semaphore);
+
+ /* Check that the block device is not memory mapped */
+ mapping = bdev->bd_inode->i_mapping;
+ mutex_lock(&mapping->i_mmap_mutex);
+ if (!prio_tree_empty(&mapping->i_mmap) ||
+ !list_empty(&mapping->i_mmap_nonlinear)) {
+ mutex_unlock(&mapping->i_mmap_mutex);
+ up_write(&bdev->bd_block_size_semaphore);
+ return -EBUSY;
+ }
+ mutex_unlock(&mapping->i_mmap_mutex);
+
/* Don't change the size if it is same as current */
if (bdev->bd_block_size != size) {
sync_blockdev(bdev);
@@ -131,6 +147,9 @@ int set_blocksize(struct block_device *bdev, int size)
bdev->bd_inode->i_blkbits = blksize_bits(size);
kill_bdev(bdev);
}
+
+ up_write(&bdev->bd_block_size_semaphore);
+
return 0;
}
@@ -472,6 +491,7 @@ static void init_once(void *foo)
inode_init_once(&ei->vfs_inode);
/* Initialize mutex for freeze. */
mutex_init(&bdev->bd_fsfreeze_mutex);
+ init_rwsem(&bdev->bd_block_size_semaphore);
}
static inline void __bd_forget(struct inode *inode)
@@ -1567,6 +1587,22 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
return blkdev_ioctl(bdev, mode, cmd, arg);
}
+ssize_t blkdev_aio_read(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ ssize_t ret;
+ struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
+
+ down_read(&bdev->bd_block_size_semaphore);
+
+ ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
+
+ up_read(&bdev->bd_block_size_semaphore);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(blkdev_aio_read);
+
/*
* Write data to the block device. Only intended for the block device itself
* and the raw driver which basically is a fake block device.
@@ -1578,12 +1614,16 @@ ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
+ struct block_device *bdev = I_BDEV(file->f_mapping->host);
struct blk_plug plug;
ssize_t ret;
BUG_ON(iocb->ki_pos != pos);
blk_start_plug(&plug);
+
+ down_read(&bdev->bd_block_size_semaphore);
+
ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
if (ret > 0 || ret == -EIOCBQUEUED) {
ssize_t err;
@@ -1592,11 +1632,29 @@ ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
if (err < 0 && ret > 0)
ret = err;
}
+
+ up_read(&bdev->bd_block_size_semaphore);
+
blk_finish_plug(&plug);
+
return ret;
}
EXPORT_SYMBOL_GPL(blkdev_aio_write);
+int blkdev_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ int ret;
+ struct block_device *bdev = I_BDEV(file->f_mapping->host);
+
+ down_read(&bdev->bd_block_size_semaphore);
+
+ ret = generic_file_mmap(file, vma);
+
+ up_read(&bdev->bd_block_size_semaphore);
+
+ return ret;
+}
+
/*
* Try to release a page associated with block device when the system
* is under memory pressure.
@@ -1627,9 +1685,9 @@ const struct file_operations def_blk_fops = {
.llseek = block_llseek,
.read = do_sync_read,
.write = do_sync_write,
- .aio_read = generic_file_aio_read,
+ .aio_read = blkdev_aio_read,
.aio_write = blkdev_aio_write,
- .mmap = generic_file_mmap,
+ .mmap = blkdev_mmap,
.fsync = blkdev_fsync,
.unlocked_ioctl = block_ioctl,
#ifdef CONFIG_COMPAT
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