[PATCH] recover from iclog allocation failures

[Eric Sandeen <sandeen@redhat.com>]

A user in #xfs had some strange thing hogging up vmalloc
space, and after mounting several xfs filesystems with 
aggressive log memory usage, started hitting vmalloc failures 
which led to an oops.

I inserted a fake failure at i=3 in the iclog alloc loop, and 
this patch let me exit with a graceful "ENOMEM" instead of an 
oops.

Also, somehow the use of "uuid_mounted" has gone stale; after
the graceful mount failure, I got dup uuid errors on the next
mount.  This patch fixes that problem as well.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

---

Index: linux-2.6.24.noarch/fs/xfs/xfs_log.c
===================================================================
--- linux-2.6.24.noarch.orig/fs/xfs/xfs_log.c
+++ linux-2.6.24.noarch/fs/xfs/xfs_log.c
@@ -513,6 +513,8 @@ xfs_log_mount(xfs_mount_t	*mp,
 	}
 
 	mp->m_log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
+	if (!mp->m_log)
+		return ENOMEM;
 
 	/*
 	 * skip log recovery on a norecovery mount.  pretend it all
@@ -1219,6 +1221,13 @@ xlog_alloc_log(xfs_mount_t	*mp,
 		prev_iclog = iclog;
 
 		bp = xfs_buf_get_noaddr(log->l_iclog_size, mp->m_logdev_targp);
+		if (!iclog || !bp) {
+			if (iclog)
+				kmem_free(iclog, sizeof(xlog_in_core_t));
+			log->l_iclog_bufs = i;
+			xlog_dealloc_log(log);
+			return NULL;
+		}
 		if (!XFS_BUF_CPSEMA(bp))
 			ASSERT(0);
 		XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
Index: linux-2.6.24.noarch/fs/xfs/xfs_mount.c
===================================================================
--- linux-2.6.24.noarch.orig/fs/xfs/xfs_mount.c
+++ linux-2.6.24.noarch/fs/xfs/xfs_mount.c
@@ -1007,6 +1007,7 @@ xfs_mountfs(
 			error = XFS_ERROR(EINVAL);
 			goto error1;
 		}
+		uuid_mounted = 1;
 	}
 
 	/*