This patch had a slight typo; fixed in the most recent patch.

- Sarthak

On Thu, Apr 20, 2023 at 10:28 AM Sarthak Kukreti sarthakkukreti@chromium.org 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") Cc: stable@vger.kernel.org Reported-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Sarthak Kukreti sarthakkukreti@chromium.org

---

block/fops.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/block/fops.c b/block/fops.c index d2e6be4e3d1c..20b1eddcbe25 100644 --- a/block/fops.c +++ b/block/fops.c @@ -648,24 +648,35 @@ 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 = truncate_bdev_range(bdev, file->f_mode, start, end);
  

•           if (error)
  

•                   goto fail;
  

•           error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
                                         len >> SECTOR_SHIFT, GFP_KERNEL,
                                         BLKDEV_ZERO_NOUNMAP);
            break;
    case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
  

•           error = truncate_bdev_range(bdev, file->f_mode, start, end);
  

•           if (error)
  

•                   goto fail;
  

•           error = 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 = truncate_bdev_range(bdev, file->f_mode, start, end);
  

•           if (!error)
  

•                   goto fail;
  

•           error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
                                         len >> SECTOR_SHIFT, GFP_KERNEL);
            break;
  

-- 2.40.0.396.gfff15efe05-goog