This is a note to let you know that I've just added the patch titled afs: Fix where page->private is set during write to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: afs-fix-where-page-private-is-set-during-write.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit e383edb03ba16ca346eabbd4a20efa730f291530 Author: David Howells <dhowells@xxxxxxxxxx> Date: Mon Oct 26 14:05:33 2020 +0000 afs: Fix where page->private is set during write [ Upstream commit f792e3ac82fe2c6c863e93187eb7ddfccab68fa7 ] In afs, page->private is set to indicate the dirty region of a page. This is done in afs_write_begin(), but that can't take account of whether the copy into the page actually worked. Fix this by moving the change of page->private into afs_write_end(). Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/afs/write.c b/fs/afs/write.c index 7fae9f8b38eb3..f28d85c38cd89 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -135,23 +135,8 @@ try_again: if (!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags) && (to < f || from > t)) goto flush_conflicting_write; - if (from < f) - f = from; - if (to > t) - t = to; - } else { - f = from; - t = to; } - priv = (unsigned long)t << AFS_PRIV_SHIFT; - priv |= f; - trace_afs_page_dirty(vnode, tracepoint_string("begin"), - page->index, priv); - if (PagePrivate(page)) - set_page_private(page, priv); - else - attach_page_private(page, (void *)priv); *_page = page; _leave(" = 0"); return 0; @@ -185,6 +170,9 @@ int afs_write_end(struct file *file, struct address_space *mapping, { struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); struct key *key = afs_file_key(file); + unsigned long priv; + unsigned int f, from = pos & (PAGE_SIZE - 1); + unsigned int t, to = from + copied; loff_t i_size, maybe_i_size; int ret; @@ -216,6 +204,29 @@ int afs_write_end(struct file *file, struct address_space *mapping, SetPageUptodate(page); } + if (PagePrivate(page)) { + priv = page_private(page); + f = priv & AFS_PRIV_MAX; + t = priv >> AFS_PRIV_SHIFT; + if (from < f) + f = from; + if (to > t) + t = to; + priv = (unsigned long)t << AFS_PRIV_SHIFT; + priv |= f; + set_page_private(page, priv); + trace_afs_page_dirty(vnode, tracepoint_string("dirty+"), + page->index, priv); + } else { + f = from; + t = to; + priv = (unsigned long)t << AFS_PRIV_SHIFT; + priv |= f; + attach_page_private(page, (void *)priv); + trace_afs_page_dirty(vnode, tracepoint_string("dirty"), + page->index, priv); + } + set_page_dirty(page); if (PageDirty(page)) _debug("dirtied");