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 <[email protected]> Signed-off-by: Rik van Riel <[email protected]> Acked-by: Larry Woodman <[email protected]> Cc: [email protected] Signed-off-by: Linus Torvalds <[email protected]>
mgowda · May 26, 2010 · 91803b4 · 91803b4
1 parent 63a6440
commit 91803b4
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/mm/filemap.c b/mm/filemap.c
@@ -1105,6 +1105,12 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos,
 		}
 
 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);