From d5b8145455c629e7f157d2da46a9b2fba483f235 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Tue, 1 Jun 2021 22:53:27 +0200 Subject: [PATCH] Revert "gfs2: Fix mmap locking for write faults" This reverts commit b7f55d928e75557295c1ac280c291b738905b6fb. As explained by Linus in [*], write faults on a mmap region are reads from a filesysten point of view, so taking the inode glock exclusively on write faults is incorrect. Instead, when a page is marked writable, the .page_mkwrite vm operation will be called, which is where the exclusive lock taking needs to happen. I got this wrong because of a broken test case that made me believe .page_mkwrite isn't getting called when it actually is. [*] https://lore.kernel.org/lkml/CAHk-=wj8EWr_D65i4oRSj2FTbrc6RdNydNNCGxeabRnwtoU=3Q@mail.gmail.com/ Signed-off-by: Andreas Gruenbacher --- fs/gfs2/file.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 8a35a0196b6d..493a83e3f590 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -540,11 +540,9 @@ static vm_fault_t gfs2_fault(struct vm_fault *vmf) struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_holder gh; vm_fault_t ret; - u16 state; int err; - state = (vmf->flags & FAULT_FLAG_WRITE) ? LM_ST_EXCLUSIVE : LM_ST_SHARED; - gfs2_holder_init(ip->i_gl, state, 0, &gh); + gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh); err = gfs2_glock_nq(&gh); if (err) { ret = block_page_mkwrite_return(err);