From 6560987b25a88f78ed53d37525d363c126a07b79 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Wed, 27 Jul 2011 17:26:12 +1000
Subject: [PATCH] Grow: ensure clean abort if we cannot read the 'completed'
 file.

If a read of 'completed' returns an error, select will never fail, so
this loop would never exit.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 Grow.c  | 10 ++++++++--
 sysfs.c |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/Grow.c b/Grow.c
index e4fc222..1aab113 100644
--- a/Grow.c
+++ b/Grow.c
@@ -2725,15 +2725,21 @@ check_progress:
 		int rv = -2;
 		tv.tv_sec = 10;
 		tv.tv_usec = 0;
-		while (fd >= 0 && rv < 0) {
+		while (fd >= 0 && rv < 0 && tv.tv_sec > 0) {
 			fd_set rfds;
 			FD_ZERO(&rfds);
 			FD_SET(fd, &rfds);
 			if (select(fd+1, NULL, NULL, &rfds, &tv) != 1)
 				break;
-			if (sysfs_fd_get_ll(fd, &completed) >= 0)
+			switch (sysfs_fd_get_ll(fd, &completed)) {
+			case 0:
 				/* all good again */
 				rv = 1;
+				break;
+			case -2: /* read error - abort */
+				tv.tv_sec = 0;
+				break;
+			}
 		}
 		if (fd >= 0)
 			close(fd);
diff --git a/sysfs.c b/sysfs.c
index 44314ba..56813b7 100644
--- a/sysfs.c
+++ b/sysfs.c
@@ -470,7 +470,7 @@ int sysfs_fd_get_ll(int fd, unsigned long long *val)
 	lseek(fd, 0, 0);
 	n = read(fd, buf, sizeof(buf));
 	if (n <= 0)
-		return -1;
+		return -2;
 	buf[n] = 0;
 	*val = strtoull(buf, &ep, 0);
 	if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))