diff mbox series

afs: Fix afs_write_end() when called with copied == 0

Message ID 160537415141.3024088.7100009150583164795.stgit@warthog.procyon.org.uk (mailing list archive)
State New, archived
Headers show
Series afs: Fix afs_write_end() when called with copied == 0 | expand

Commit Message

David Howells Nov. 14, 2020, 5:15 p.m. UTC
When afs_write_end() is called with copied == 0, it tries to set the dirty
region, but there's no way to actually encode a 0-length region in the
encoding in page->private.  "0,0", for example, indicates a 1-byte region
at offset 0.  The maths miscalculates this and sets it incorrectly.

Fix it to just do nothing but unlock and put the page in this case.  We
don't actually need to mark the page dirty as nothing presumably changed.

Fixes: 65dd2d6072d3 ("afs: Alter dirty range encoding in page->private")
Signed-off-by: David Howells <dhowells@redhat.com>

 fs/afs/write.c |    3 +++
 1 file changed, 3 insertions(+)


David Howells Nov. 14, 2020, 5:26 p.m. UTC | #1
Oops.  I forgot to compile it after picking it from a patch series.  There's
an uninitialised warning in it.

diff mbox series


diff --git a/fs/afs/write.c b/fs/afs/write.c
index 50371207f327..f34d13d294fa 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -174,6 +174,9 @@  int afs_write_end(struct file *file, struct address_space *mapping,
 	       vnode->fid.vid, vnode->fid.vnode, page->index);
+	if (copied == 0)
+		goto out;
 	maybe_i_size = pos + copied;
 	i_size = i_size_read(&vnode->vfs_inode);