diff options
| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2023-11-09 21:06:04 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-12-29 11:58:22 -0800 |
| commit | 5f3bd90d9b98855c2e811aa3b4823d583b0020df (patch) | |
| tree | 9273918c69f3432602cd2cbccd2a27ca0583ed32 /fs/buffer.c | |
| parent | 382497ada051a6fc79612aba5e30cdfa26364374 (diff) | |
buffer: fix grow_buffers() for block size > PAGE_SIZE
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>
Signed-off-by: Nathan Chancellor <nathan@kernel.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>
[nathan@kernel.org: add cast in grow_buffers() to avoid a multiplication libcall]
Link: https://lkml.kernel.org/r/20231128-avoid-muloti4-grow_buffers-v1-1-bc3d0f0ec483@kernel.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/buffer.c')
| -rw-r--r-- | fs/buffer.c | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index 44e0c0b7f71f..f765a95034cf 100644 --- a/fs/buffer.c +++ b/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, (sector_t)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 * |