From: Jeff Moyer Date: Wed, 26 May 2010 15:49:40 +0000 (-0400) Subject: do_generic_file_read: clear page errors when issuing a fresh read of the page X-Git-Tag: v2.6.35-rc1~250 X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=91803b499cca2fe558abad709ce83dc896b80950;hp=63a6440326e4cd01d6a663069208a0e68e9b833f do_generic_file_read: clear page errors when issuing a fresh read of the page I/O errors can happen due to temporary failures, like multipath errors or losing network contact with the iSCSI server. Because of that, the VM will retry readpage on the page. However, do_generic_file_read does not clear PG_error. This causes the system to be unable to actually use the data in the page cache page, even if the subsequent readpage completes successfully! The function filemap_fault has had a ClearPageError before readpage forever. This patch simply adds the same to do_generic_file_read. Signed-off-by: Jeff Moyer Signed-off-by: Rik van Riel Acked-by: Larry Woodman Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- diff --git a/mm/filemap.c b/mm/filemap.c index 88d7196..35e12d1 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1105,6 +1105,12 @@ page_not_up_to_date_locked: } readpage: + /* + * A previous I/O error may have been due to temporary + * failures, eg. multipath errors. + * PG_error will be set again if readpage fails. + */ + ClearPageError(page); /* Start the actual read. The read will unlock the page. */ error = mapping->a_ops->readpage(filp, page);