From: Kazuya Mio <k-mio@sx.jp.nec.com>
Date: Thu, 20 Oct 2011 23:23:08 +0000 (-0400)
Subject: ext4: fix the deadlock in mpage_da_map_and_submit()
X-Git-Tag: v2.6.39-400.9.0~565^2~2^2~3
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=06fc8123dfac181971fa4578947cedb8d70708b1;p=users%2Fjedix%2Flinux-maple.git

ext4: fix the deadlock in mpage_da_map_and_submit()

If ext4_jbd2_file_inode() in mpage_da_map_and_submit() fails due to
journal abort, this function returns to caller without unlocking the
page.  It leads to the deadlock, and the patch fixes this issue by
calling mpage_da_submit_io().

Signed-off-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

Conflicts:

	fs/ext4/inode.c
---

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index fa805e7527e6..00523341b77a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2339,13 +2339,15 @@ static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
 
 		for (i = 0; i < map.m_len; i++)
 			unmap_underlying_metadata(bdev, map.m_pblk + i);
-	}
 
-	if (ext4_should_order_data(mpd->inode)) {
-		err = ext4_jbd2_file_inode(handle, mpd->inode);
-		if (err)
-			/* This only happens if the journal is aborted */
-			return;
+		if (ext4_should_order_data(mpd->inode)) {
+			err = ext4_jbd2_file_inode(handle, mpd->inode);
+			if (err) {
+				/* Only if the journal is aborted */
+				mpd->retval = err;
+				goto submit_io;
+			}
+		}
 	}
 
 	/*
@@ -3041,11 +3043,12 @@ retry:
 			ret = 0;
 		} else if (ret == MPAGE_DA_EXTENT_TAIL) {
 			/*
-			 * got one extent now try with
-			 * rest of the pages
+			 * Got one extent now try with rest of the pages.
+			 * If mpd.retval is set -EIO, journal is aborted.
+			 * So we don't need to write any more.
 			 */
 			pages_written += mpd.pages_written;
-			ret = 0;
+			ret = mpd.retval;
 			io_done = 1;
 		} else if (wbc->nr_to_write)
 			/*