Commit 75f1dc0d authored by Tejun Heo's avatar Tejun Heo
Browse files

block: check bdev_read_only() from blkdev_get() 



bdev read-only status can be queried using bdev_read_only() and may
change while the device is being opened.  Enforce it by checking it
from blkdev_get() after open succeeds.

This makes bdev_read_only() check in open_bdev_exclusive() and
fsg_lun_open() unnecessary.  Drop them.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: linux-usb@vger.kernel.org
parent 6a027eff

drivers/usb/gadget/storage_common.c

+2 −5
Original line number Diff line number Diff line
@@ -543,7 +543,7 @@ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename) 
	ro = curlun->initially_ro;

	if (!ro) {

		filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);

		if (-EROFS == PTR_ERR(filp))

		if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)

			ro = 1;

	}

	if (ro)
@@ -558,10 +558,7 @@ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename) 


	if (filp->f_path.dentry)

		inode = filp->f_path.dentry->d_inode;

	if (inode && S_ISBLK(inode->i_mode)) {

		if (bdev_read_only(inode->i_bdev))

			ro = 1;

	} else if (!inode || !S_ISREG(inode->i_mode)) {

	if (!inode || (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {

		LINFO(curlun, "invalid file type: %s\n", filename);

		goto out;

	}

fs/block_dev.c

+6 −5
Original line number Diff line number Diff line
@@ -1149,6 +1149,12 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) 


	res = __blkdev_get(bdev, mode, 0);



	/* __blkdev_get() may alter read only status, check it afterwards */

	if (!res && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {

		__blkdev_put(bdev, mode, 0);

		res = -EACCES;

	}



	if (whole) {

		/* finish claiming */

		spin_lock(&bdev_lock);
@@ -1453,11 +1459,6 @@ struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *h 
	if (error)

		return ERR_PTR(error);



	if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {

		blkdev_put(bdev, mode);

		return ERR_PTR(-EACCES);

	}



	return bdev;

}

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