1 files changed, 72 insertions, 37 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d3a25b027ff9..edbaac6c0573 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -40,8 +40,7 @@
  * Heinz Mauelshagen <mge@sistina.com>, Feb 2002
  *
  * Support for falling back on the write file operation when the address space
- * operations prepare_write and/or commit_write are not available on the
- * backing filesystem.
+ * operations write_begin is not available on the backing filesystem.
  * Anton Altaparmakov, 16 Feb 2005
  *
  * Still To Fix:
@@ -210,7 +209,7 @@ lo_do_transfer(struct loop_device *lo, int cmd,
  * space operations write_begin and write_end.
  */
 static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
-		int bsize, loff_t pos, struct page *unused)
+		loff_t pos, struct page *unused)
 {
 	struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */
 	struct address_space *mapping = file->f_mapping;
@@ -302,7 +301,7 @@ static int __do_lo_send_write(struct file *file,
  * filesystems.
  */
 static int do_lo_send_direct_write(struct loop_device *lo,
-		struct bio_vec *bvec, int bsize, loff_t pos, struct page *page)
+		struct bio_vec *bvec, loff_t pos, struct page *page)
 {
 	ssize_t bw = __do_lo_send_write(lo->lo_backing_file,
 			kmap(bvec->bv_page) + bvec->bv_offset,
@@ -326,7 +325,7 @@ static int do_lo_send_direct_write(struct loop_device *lo,
  * destination pages of the backing file.
  */
 static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,
-		int bsize, loff_t pos, struct page *page)
+		loff_t pos, struct page *page)
 {
 	int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page,
 			bvec->bv_offset, bvec->bv_len, pos >> 9);
@@ -341,10 +340,9 @@ static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,
 	return ret;
 }
 
-static int lo_send(struct loop_device *lo, struct bio *bio, int bsize,
-		loff_t pos)
+static int lo_send(struct loop_device *lo, struct bio *bio, loff_t pos)
 {
-	int (*do_lo_send)(struct loop_device *, struct bio_vec *, int, loff_t,
+	int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t,
 			struct page *page);
 	struct bio_vec *bvec;
 	struct page *page = NULL;
@@ -362,7 +360,7 @@ static int lo_send(struct loop_device *lo, struct bio *bio, int bsize,
 		}
 	}
 	bio_for_each_segment(bvec, bio, i) {
-		ret = do_lo_send(lo, bvec, bsize, pos, page);
+		ret = do_lo_send(lo, bvec, pos, page);
 		if (ret < 0)
 			break;
 		pos += bvec->bv_len;
@@ -478,7 +476,7 @@ static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
 
 	pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset;
 	if (bio_rw(bio) == WRITE)
-		ret = lo_send(lo, bio, lo->lo_blocksize, pos);
+		ret = lo_send(lo, bio, pos);
 	else
 		ret = lo_receive(lo, bio, lo->lo_blocksize, pos);
 	return ret;
@@ -626,20 +624,38 @@ static int loop_switch(struct loop_device *lo, struct file *file)
 }
 
 /*
+ * Helper to flush the IOs in loop, but keeping loop thread running
+ */
+static int loop_flush(struct loop_device *lo)
+{
+	/* loop not yet configured, no running thread, nothing to flush */
+	if (!lo->lo_thread)
+		return 0;
+
+	return loop_switch(lo, NULL);
+}
+
+/*
  * Do the actual switch; called from the BIO completion routine
  */
 static void do_loop_switch(struct loop_device *lo, struct switch_request *p)
 {
 	struct file *file = p->file;
 	struct file *old_file = lo->lo_backing_file;
-	struct address_space *mapping = file->f_mapping;
+	struct address_space *mapping;
+
+	/* if no new file, only flush of queued bios requested */
+	if (!file)
+		goto out;
 
+	mapping = file->f_mapping;
 	mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
 	lo->lo_backing_file = file;
 	lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ?
 		mapping->host->i_bdev->bd_block_size : PAGE_SIZE;
 	lo->old_gfp_mask = mapping_gfp_mask(mapping);
 	mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
+out:
 	complete(&p->wait);
 }
 
@@ -652,8 +668,8 @@ static void do_loop_switch(struct loop_device *lo, struct switch_request *p)
  * This can only work if the loop device is used read-only, and if the
  * new backing store is the same size and type as the old backing store.
  */
-static int loop_change_fd(struct loop_device *lo, struct file *lo_file,
-		       struct block_device *bdev, unsigned int arg)
+static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
+			  unsigned int arg)
 {
 	struct file	*file, *old_file;
 	struct inode	*inode;
@@ -712,7 +728,7 @@ static inline int is_loop_device(struct file *file)
 	return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR;
 }
 
-static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
+static int loop_set_fd(struct loop_device *lo, fmode_t mode,
 		       struct block_device *bdev, unsigned int arg)
 {
 	struct file	*file, *f;
@@ -740,7 +756,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
 	while (is_loop_device(f)) {
 		struct loop_device *l;
 
-		if (f->f_mapping->host->i_rdev == lo_file->f_mapping->host->i_rdev)
+		if (f->f_mapping->host->i_bdev == bdev)
 			goto out_putf;
 
 		l = f->f_mapping->host->i_bdev->bd_disk->private_data;
@@ -766,7 +782,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
 		 */
 		if (!file->f_op->splice_read)
 			goto out_putf;
-		if (aops->prepare_write || aops->write_begin)
+		if (aops->write_begin)
 			lo_flags |= LO_FLAGS_USE_AOPS;
 		if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write)
 			lo_flags |= LO_FLAGS_READ_ONLY;
@@ -786,7 +802,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
 		goto out_putf;
 	}
 
-	if (!(lo_file->f_mode & FMODE_WRITE))
+	if (!(mode & FMODE_WRITE))
 		lo_flags |= LO_FLAGS_READ_ONLY;
 
 	set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
@@ -903,6 +919,7 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
 
 	kthread_stop(lo->lo_thread);
 
+	lo->lo_queue->unplug_fn = NULL;
 	lo->lo_backing_file = NULL;
 
 	loop_release_xfer(lo);
@@ -918,9 +935,11 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
 	memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
 	memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
 	memset(lo->lo_file_name, 0, LO_NAME_SIZE);
-	invalidate_bdev(bdev);
+	if (bdev)
+		invalidate_bdev(bdev);
 	set_capacity(lo->lo_disk, 0);
-	bd_set_size(bdev, 0);
+	if (bdev)
+		bd_set_size(bdev, 0);
 	mapping_set_gfp_mask(filp->f_mapping, gfp);
 	lo->lo_state = Lo_unbound;
 	fput(filp);
@@ -936,8 +955,10 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 {
 	int err;
 	struct loop_func_table *xfer;
+	uid_t uid = current_uid();
 
-	if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid &&
+	if (lo->lo_encrypt_key_size &&
+	    lo->lo_key_owner != uid &&
 	    !capable(CAP_SYS_ADMIN))
 		return -EPERM;
 	if (lo->lo_state != Lo_bound)
@@ -992,7 +1013,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 	if (info->lo_encrypt_key_size) {
 		memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
 		       info->lo_encrypt_key_size);
-		lo->lo_key_owner = current->uid;
+		lo->lo_key_owner = uid;
 	}	
 
 	return 0;
@@ -1137,22 +1158,22 @@ loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) {
 	return err;
 }
 
-static int lo_ioctl(struct inode * inode, struct file * file,
+static int lo_ioctl(struct block_device *bdev, fmode_t mode,
 	unsigned int cmd, unsigned long arg)
 {
-	struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
+	struct loop_device *lo = bdev->bd_disk->private_data;
 	int err;
 
 	mutex_lock(&lo->lo_ctl_mutex);
 	switch (cmd) {
 	case LOOP_SET_FD:
-		err = loop_set_fd(lo, file, inode->i_bdev, arg);
+		err = loop_set_fd(lo, mode, bdev, arg);
 		break;
 	case LOOP_CHANGE_FD:
-		err = loop_change_fd(lo, file, inode->i_bdev, arg);
+		err = loop_change_fd(lo, bdev, arg);
 		break;
 	case LOOP_CLR_FD:
-		err = loop_clr_fd(lo, inode->i_bdev);
+		err = loop_clr_fd(lo, bdev);
 		break;
 	case LOOP_SET_STATUS:
 		err = loop_set_status_old(lo, (struct loop_info __user *) arg);
@@ -1292,10 +1313,10 @@ loop_get_status_compat(struct loop_device *lo,
 	return err;
 }
 
-static long lo_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
+			   unsigned int cmd, unsigned long arg)
 {
-	struct inode *inode = file->f_path.dentry->d_inode;
-	struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
+	struct loop_device *lo = bdev->bd_disk->private_data;
 	int err;
 
 	switch(cmd) {
@@ -1317,7 +1338,7 @@ static long lo_compat_ioctl(struct file *file, unsigned int cmd, unsigned long a
 		arg = (unsigned long) compat_ptr(arg);
 	case LOOP_SET_FD:
 	case LOOP_CHANGE_FD:
-		err = lo_ioctl(inode, file, cmd, arg);
+		err = lo_ioctl(bdev, mode, cmd, arg);
 		break;
 	default:
 		err = -ENOIOCTLCMD;
@@ -1327,9 +1348,9 @@ static long lo_compat_ioctl(struct file *file, unsigned int cmd, unsigned long a
 }
 #endif
 
-static int lo_open(struct inode *inode, struct file *file)
+static int lo_open(struct block_device *bdev, fmode_t mode)
 {
-	struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
+	struct loop_device *lo = bdev->bd_disk->private_data;
 
 	mutex_lock(&lo->lo_ctl_mutex);
 	lo->lo_refcnt++;
@@ -1338,16 +1359,30 @@ static int lo_open(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static int lo_release(struct inode *inode, struct file *file)
+static int lo_release(struct gendisk *disk, fmode_t mode)
 {
-	struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
+	struct loop_device *lo = disk->private_data;
 
 	mutex_lock(&lo->lo_ctl_mutex);
-	--lo->lo_refcnt;
 
-	if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) && !lo->lo_refcnt)
-		loop_clr_fd(lo, inode->i_bdev);
+	if (--lo->lo_refcnt)
+		goto out;
 
+	if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
+		/*
+		 * In autoclear mode, stop the loop thread
+		 * and remove configuration after last close.
+		 */
+		loop_clr_fd(lo, NULL);
+	} else {
+		/*
+		 * Otherwise keep thread (if running) and config,
+		 * but flush possible ongoing bios in thread.
+		 */
+		loop_flush(lo);
+	}
+
+out:
 	mutex_unlock(&lo->lo_ctl_mutex);
 
 	return 0;