-stable review patch. If anyone has any objections, please let us know.
------------------
From: Linus Torvalds <[email protected]>
Fix up CIFS for "test_clear_page_dirty()" removal
This also adds he required page "writeback" flag handling, that cifs
hasn't been doing and that the page dirty flag changes made obvious.
Acked-by: Steve French <[email protected]>
Acked-by: Dave Kleikamp <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
This fixes a long term corruption bug when copying large files to a CIFS
mount. Thanks Linus!
---
fs/cifs/file.c | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)
--- linux-2.6.19.2.orig/fs/cifs/file.c
+++ linux-2.6.19.2/fs/cifs/file.c
@@ -1244,14 +1244,21 @@ retry:
wait_on_page_writeback(page);
if (PageWriteback(page) ||
- !test_clear_page_dirty(page)) {
+ !clear_page_dirty_for_io(page)) {
unlock_page(page);
break;
}
+ /*
+ * This actually clears the dirty bit in the radix tree.
+ * See cifs_writepage() for more commentary.
+ */
+ set_page_writeback(page);
+
if (page_offset(page) >= mapping->host->i_size) {
done = 1;
unlock_page(page);
+ end_page_writeback(page);
break;
}
@@ -1315,6 +1322,7 @@ retry:
SetPageError(page);
kunmap(page);
unlock_page(page);
+ end_page_writeback(page);
page_cache_release(page);
}
if ((wbc->nr_to_write -= n_iov) <= 0)
@@ -1351,11 +1359,23 @@ static int cifs_writepage(struct page* p
if (!PageUptodate(page)) {
cFYI(1, ("ppw - page not up to date"));
}
-
+
+ /*
+ * Set the "writeback" flag, and clear "dirty" in the radix tree.
+ *
+ * A writepage() implementation always needs to do either this,
+ * or re-dirty the page with "redirty_page_for_writepage()" in
+ * the case of a failure.
+ *
+ * Just unlocking the page will cause the radix tree tag-bits
+ * to fail to update with the state of the page correctly.
+ */
+ set_page_writeback(page);
rc = cifs_partialpagewrite(page, 0, PAGE_CACHE_SIZE);
SetPageUptodate(page); /* BB add check for error and Clearuptodate? */
unlock_page(page);
- page_cache_release(page);
+ end_page_writeback(page);
+ page_cache_release(page);
FreeXid(xid);
return rc;
}
--
-
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