From 7294eb6cae4b201c481b2a171d042c56b810b8b3 Mon Sep 17 00:00:00 2001
From: Nick Kralevich <nnk@google.com>
Date: Thu, 5 Feb 2015 16:02:42 -0800
Subject: [PATCH] fs_mgr: error check umount calls / add retry logic

Don't silently ignore umount errors. At a minimum, log them.

Add strerror(errno) to another umount call, to make sure we get
some actionable data.

check_fs: try 5 times umounting the filesystem. It appears that
the umount is failing, perhaps because some service is opening
the file on the device or other error. Try unmounting it multiple
times in case it's a transient problem and we can recover.

Bug: 19199624
Bug: 19156134
Change-Id: I7213eb52d55116fb2419a36494d26d5e159981a7
---
 fs_mgr/fs_mgr.c      | 16 +++++++++++++---
 fs_mgr/fs_mgr_priv.h |  1 +
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/fs_mgr/fs_mgr.c b/fs_mgr/fs_mgr.c
index fa52d1601..a1391e045 100644
--- a/fs_mgr/fs_mgr.c
+++ b/fs_mgr/fs_mgr.c
@@ -119,7 +119,17 @@ static void check_fs(char *blk_device, char *fs_type, char *target)
         ret = mount(blk_device, target, fs_type, tmpmnt_flags, tmpmnt_opts);
         INFO("%s(): mount(%s,%s,%s)=%d\n", __func__, blk_device, target, fs_type, ret);
         if (!ret) {
-            umount(target);
+            int i;
+            for (i = 0; i < 5; i++) {
+                // Try to umount 5 times before continuing on.
+                // Should we try rebooting if all attempts fail?
+                int result = umount(target);
+                if (result == 0) {
+                    break;
+                }
+                ERROR("%s(): umount(%s)=%d: %s\n", __func__, target, result, strerror(errno));
+                sleep(1);
+            }
         }
 
         /*
@@ -488,8 +498,8 @@ int fs_mgr_mount_all(struct fstab *fstab)
                         encryptable = FS_MGR_MNTALL_DEV_MIGHT_BE_ENCRYPTED;
                     }
                 } else {
-                    INFO("Could not umount %s - allow continue unencrypted\n",
-                         fstab->recs[attempted_idx].mount_point);
+                    WARNING("Could not umount %s (%s) - allow continue unencrypted\n",
+                            fstab->recs[attempted_idx].mount_point, strerror(errno));
                     continue;
                 }
             }
diff --git a/fs_mgr/fs_mgr_priv.h b/fs_mgr/fs_mgr_priv.h
index 34938fad7..4ba6f92bc 100644
--- a/fs_mgr/fs_mgr_priv.h
+++ b/fs_mgr/fs_mgr_priv.h
@@ -21,6 +21,7 @@
 #include <fs_mgr.h>
 
 #define INFO(x...)    KLOG_INFO("fs_mgr", x)
+#define WARNING(x...) KLOG_WARNING("fs_mgr", x)
 #define ERROR(x...)   KLOG_ERROR("fs_mgr", x)
 
 #define CRYPTO_TMPFS_OPTIONS "size=256m,mode=0771,uid=1000,gid=1000"