From: John Garry Date: Wed, 27 Nov 2024 09:23:18 +0000 (+0000) Subject: block: Don't allow an atomic write be truncated in blkdev_write_iter() X-Git-Tag: v6.11.11~17 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7ef523e499ef95f43da8285998b7914f6a3ca2c6;p=thirdparty%2Fkernel%2Fstable.git block: Don't allow an atomic write be truncated in blkdev_write_iter() [ Upstream commit 2cbd51f1f8739fd2fdf4bae1386bcf75ce0176ba ] A write which goes past the end of the bdev in blkdev_write_iter() will be truncated. Truncating cannot tolerated for an atomic write, so error that condition. Fixes: caf336f81b3a ("block: Add fops atomic write support") Signed-off-by: John Garry Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20241127092318.632790-1-john.g.garry@oracle.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- diff --git a/block/fops.c b/block/fops.c index 56db751bba49b..16bb5ae702379 100644 --- a/block/fops.c +++ b/block/fops.c @@ -676,6 +676,7 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) struct file *file = iocb->ki_filp; struct inode *bd_inode = bdev_file_inode(file); struct block_device *bdev = I_BDEV(bd_inode); + bool atomic = iocb->ki_flags & IOCB_ATOMIC; loff_t size = bdev_nr_bytes(bdev); size_t shorted = 0; ssize_t ret; @@ -695,7 +696,7 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) return -EOPNOTSUPP; - if (iocb->ki_flags & IOCB_ATOMIC) { + if (atomic) { ret = generic_atomic_write_valid(iocb, from); if (ret) return ret; @@ -703,6 +704,8 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) size -= iocb->ki_pos; if (iov_iter_count(from) > size) { + if (atomic) + return -EINVAL; shorted = iov_iter_count(from) - size; iov_iter_truncate(from, size); }