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authorAndreas Gruenbacher <agruenba@redhat.com>2021-06-01 22:53:27 +0200
committerAndreas Gruenbacher <agruenba@redhat.com>2021-06-01 23:16:42 +0200
commitd5b8145455c629e7f157d2da46a9b2fba483f235 (patch)
treea940ad03fdaffc9b7914cfb6e466d01f37861713 /fs/gfs2
parentc2131f7e73c9e9365613e323d65c7b9e5b910f56 (diff)
downloadlinux-d5b8145455c629e7f157d2da46a9b2fba483f235.tar.gz
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 <agruenba@redhat.com>
Diffstat (limited to 'fs/gfs2')
-rw-r--r--fs/gfs2/file.c4
1 files changed, 1 insertions, 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);