From: Christoph Hellwig <hch@lst.de>
Date: Fri, 3 May 2024 05:48:42 +0000 (+0200)
Subject: block: refine the EOF check in blkdev_iomap_begin
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=refs%2Fheads%2Fblkdev_iomap_begin-fix;p=users%2Fhch%2Fblock.git

block: refine the EOF check in blkdev_iomap_begin

blkdev_iomap_begin rounds down the offset to the logical block size
before stashing it in iomap->offset and checking that it still is
inside the inode size.

Check the i_size check to the raw pos value so that we don't try a
zero size write if iter->pos is unaligned.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---

diff --git a/block/fops.c b/block/fops.c
index 679d9b752fe8..df2c68d3f198 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -390,7 +390,7 @@ static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 
 	iomap->bdev = bdev;
 	iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
-	if (iomap->offset >= isize)
+	if (offset >= isize)
 		return -EIO;
 	iomap->type = IOMAP_MAPPED;
 	iomap->addr = iomap->offset;