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afs: Fix to take ref on page when PG_private is set

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Fix afs to take a ref on a page when it sets PG_private on it and to drop
the ref when removing the flag.

Note that in afs_write_begin(), a lot of the time, PG_private is already
set on a page to which we're going to add some data.  In such a case, we
leave the bit set and mustn't increment the page count.

As suggested by Matthew Wilcox, use attach/detach_page_private() where
possible.

Fixes: 31143d5d51 ("AFS: implement basic file write support")
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
This commit is contained in:
David Howells
2020-10-21 13:22:19 +01:00
parent d383e346f9
commit fa04a40b16
4 changed files with 18 additions and 26 deletions
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8
fs/afs/file.c
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@@ -627,11 +627,9 @@ static void afs_invalidatepage(struct page *page, unsigned int offset,
#endif
if (PagePrivate(page)) {
priv = page_private(page);
priv = (unsigned long)detach_page_private(page);
trace_afs_page_dirty(vnode, tracepoint_string("inval"),
page->index, priv);
set_page_private(page, 0);
ClearPagePrivate(page);
}
}
@@ -661,11 +659,9 @@ static int afs_releasepage(struct page *page, gfp_t gfp_flags)
#endif
if (PagePrivate(page)) {
priv = page_private(page);
priv = (unsigned long)detach_page_private(page);
trace_afs_page_dirty(vnode, tracepoint_string("rel"),
page->index, priv);
set_page_private(page, 0);
ClearPagePrivate(page);
}
/* indicate that the page can be released */