--- /dev/null
+From 1364a3c391aedfeb32aa025303ead3d7c91cdf9d Mon Sep 17 00:00:00 2001
+From: Sarthak Kukreti <sarthakkukreti@chromium.org>
+Date: Wed, 11 Oct 2023 13:12:30 -0700
+Subject: block: Don't invalidate pagecache for invalid falloc modes
+
+From: Sarthak Kukreti <sarthakkukreti@chromium.org>
+
+commit 1364a3c391aedfeb32aa025303ead3d7c91cdf9d upstream.
+
+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>
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
+Signed-off-by: Mike Snitzer <snitzer@kernel.org>
+Fixes: line? I've never seen those wrapped.
+Link: https://lore.kernel.org/r/20231011201230.750105-1-sarthakkukreti@chromium.org
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ block/fops.c | 21 ++++++++++++++++-----
+ 1 file changed, 16 insertions(+), 5 deletions(-)
+
+--- a/block/fops.c
++++ b/block/fops.c
+@@ -655,24 +655,35 @@ static long blkdev_fallocate(struct file
+
+ 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;