[PATCH stable 6.11.y] netfs: reset subreq->iov_iter before netfs_clear_unread() tail clean

[Christian Ebner <c.ebner@proxmox.com>]

Fixes file corruption issues when reading contents via ceph client.

Call netfs_reset_subreq_iter() to align subreq->io_iter before
calling netfs_clear_unread() to clear tail, as subreq->io_iter count
and subreq->transferred might not be aligned after incomplete I/O,
having the subreq's NETFS_SREQ_CLEAR_TAIL set.

Based on ee4cdf7b ("netfs: Speed up buffered reading"), which
introduces a fix for the issue in mainline.

Fixes: 92b6cc5d ("netfs: Add iov_iters to (sub)requests to describe various buffers")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219237
Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
---
Sending this patch in an attempt to backport the fix introduced by
commit ee4cdf7b ("netfs: Speed up buffered reading"), which however
can not be cherry picked for older kernels, as the patch is not
independent from other commits and touches a lot of unrelated (to
the fix) code.

 fs/netfs/io.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/netfs/io.c b/fs/netfs/io.c
index d6ada4eba744..500119285346 100644
--- a/fs/netfs/io.c
+++ b/fs/netfs/io.c
@@ -528,6 +528,7 @@ void netfs_subreq_terminated(struct netfs_io_subrequest *subreq,
 
 incomplete:
 	if (test_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags)) {
+		netfs_reset_subreq_iter(rreq, subreq);
 		netfs_clear_unread(subreq);
 		subreq->transferred = subreq->len;
 		goto complete;
-- 
2.39.5