+ buffer-fix-grow_buffers-for-block-size-page_size.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: buffer: fix grow_buffers() for block size > PAGE_SIZE
has been added to the -mm mm-unstable branch.  Its filename is
     buffer-fix-grow_buffers-for-block-size-page_size.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/buffer-fix-grow_buffers-for-block-size-page_size.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: buffer: fix grow_buffers() for block size > PAGE_SIZE
Date: Thu, 9 Nov 2023 21:06:04 +0000

We must not shift by a negative number so work in terms of a byte offset
to avoid the awkward shift left-or-right-depending-on-sign option.  This
means we need to use check_mul_overflow() to ensure that a large block
number does not result in a wrap.

Link: https://lkml.kernel.org/r/20231109210608.2252323-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/buffer.c |   17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

--- a/fs/buffer.c~buffer-fix-grow_buffers-for-block-size-page_size
+++ a/fs/buffer.c
@@ -1085,26 +1085,21 @@ unlock:
 static bool grow_buffers(struct block_device *bdev, sector_t block,
 		unsigned size, gfp_t gfp)
 {
-	pgoff_t index;
-	int sizebits;
-
-	sizebits = PAGE_SHIFT - __ffs(size);
-	index = block >> sizebits;
+	loff_t pos;
 
 	/*
-	 * Check for a block which wants to lie outside our maximum possible
-	 * pagecache index.  (this comparison is done using sector_t types).
+	 * Check for a block which lies outside our maximum possible
+	 * pagecache index.
 	 */
-	if (unlikely(index != block >> sizebits)) {
-		printk(KERN_ERR "%s: requested out-of-range block %llu for "
-			"device %pg\n",
+	if (check_mul_overflow(block, size, &pos) || pos > MAX_LFS_FILESIZE) {
+		printk(KERN_ERR "%s: requested out-of-range block %llu for device %pg\n",
 			__func__, (unsigned long long)block,
 			bdev);
 		return false;
 	}
 
 	/* Create a folio with the proper size buffers */
-	return grow_dev_folio(bdev, block, index, size, gfp);
+	return grow_dev_folio(bdev, block, pos / PAGE_SIZE, size, gfp);
 }
 
 static struct buffer_head *
_

Patches currently in -mm which might be from willy@infradead.org are

mm-add-folio_zero_tail-and-use-it-in-ext4.patch
mm-add-folio_fill_tail-and-use-it-in-iomap.patch
gfs2-convert-stuffed_readpage-to-stuffed_read_folio.patch
mm-remove-test_set_page_writeback.patch
afs-do-not-test-the-return-value-of-folio_start_writeback.patch
smb-do-not-test-the-return-value-of-folio_start_writeback.patch
mm-return-void-from-folio_start_writeback-and-related-functions.patch
mm-make-mapping_evict_folio-the-preferred-way-to-evict-clean-folios.patch
mm-convert-__do_fault-to-use-a-folio.patch
mm-use-mapping_evict_folio-in-truncate_error_page.patch
mm-convert-soft_offline_in_use_page-to-use-a-folio.patch
mm-convert-isolate_page-to-mf_isolate_folio.patch
mm-remove-invalidate_inode_page.patch
buffer-return-bool-from-grow_dev_folio.patch
buffer-calculate-block-number-inside-folio_init_buffers.patch
buffer-fix-grow_buffers-for-block-size-page_size.patch
buffer-cast-block-to-loff_t-before-shifting-it.patch
buffer-fix-various-functions-for-block-size-page_size.patch
buffer-handle-large-folios-in-__block_write_begin_int.patch
buffer-fix-more-functions-for-block-size-page_size.patch