On Wed, Apr 19, 2023 at 05:48:46PM -0700, Sarthak Kukreti wrote:
> Only call truncate_bdev_range() if the fallocate mode is
> supported. This fixes a bug where data in the pagecache
> could be invalidated if the fallocate() was called on the
> block device with an invalid mode.
>
> Fixes: 25f4c41415e5 ("block: implement (some of) fallocate for block devices")
> Signed-off-by: Sarthak Kukreti <sarthakkukreti@xxxxxxxxxxxx>
> ---
> block/fops.c | 18 ++++++++++--------
> 1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/block/fops.c b/block/fops.c
> index d2e6be4e3d1c..2fd7e8b9ab48 100644
> --- a/block/fops.c
> +++ b/block/fops.c
> @@ -648,25 +648,27 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
>
> filemap_invalidate_lock(inode->i_mapping);
>
> - /* Invalidate the page cache, including dirty pages. */
> - error = truncate_bdev_range(bdev, file->f_mode, start, end);
> - if (error)
> - goto fail;
> -
> + /*
> + * Invalidate the page cache, including dirty pages, for valid
> + * de-allocate mode calls to fallocate().
> + */
> switch (mode) {
> case FALLOC_FL_ZERO_RANGE:
> case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
> - error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
> + error = truncate_bdev_range(bdev, file->f_mode, start, end) ||
> + blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
I'm pretty sure we're supposed to preserve the error codes returned by
both functions.
error = truncate_bdev_range(...);
if (!error)
error = blkdev_issue_zeroout(...);
--D
> len >> SECTOR_SHIFT, GFP_KERNEL,
> BLKDEV_ZERO_NOUNMAP);
> break;
> case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
> - error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
> + error = truncate_bdev_range(bdev, file->f_mode, start, end) ||
> + blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
> len >> SECTOR_SHIFT, GFP_KERNEL,
> BLKDEV_ZERO_NOFALLBACK);
> break;
> case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE:
> - error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
> + error = truncate_bdev_range(bdev, file->f_mode, start, end) ||
> + blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
> len >> SECTOR_SHIFT, GFP_KERNEL);
> break;
> default:
> --
> 2.40.0.634.g4ca3ef3211-goog
>
--
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