From d5db0f97fbbeff11c88dec1aaf1536a975afbaeb Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@sandeen.net>
Date: Fri, 5 Feb 2010 22:59:53 +0000
Subject: xfs: more reserved blocks fixups

This mangles the reserved blocks counts a little more.

1) add a helper function for the default reserved count
2) add helper functions to save/restore counts on ro/rw
3) save/restore reserved blocks on freeze/thaw
4) disallow changing reserved count while readonly

V2: changed field name to match Dave's changes

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Alex Elder <aelder@sgi.com>
---
 fs/xfs/linux-2.6/xfs_ioctl.c |  3 +++
 fs/xfs/linux-2.6/xfs_super.c | 51 ++++++++++++++++++++++++++++++++------------
 2 files changed, 40 insertions(+), 14 deletions(-)

(limited to 'fs/xfs/linux-2.6')

diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
index 3906e85abfdc..4ea1ee18aded 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl.c
@@ -1431,6 +1431,9 @@ xfs_file_ioctl(
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 
+		if (mp->m_flags & XFS_MOUNT_RDONLY)
+			return -XFS_ERROR(EROFS);
+
 		if (copy_from_user(&inout, arg, sizeof(inout)))
 			return -XFS_ERROR(EFAULT);
 
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index e9c21454b9e2..6ce828e0e17b 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1256,6 +1256,29 @@ xfs_fs_statfs(
 	return 0;
 }
 
+STATIC void
+xfs_save_resvblks(struct xfs_mount *mp)
+{
+	__uint64_t resblks = 0;
+
+	mp->m_resblks_save = mp->m_resblks;
+	xfs_reserve_blocks(mp, &resblks, NULL);
+}
+
+STATIC void
+xfs_restore_resvblks(struct xfs_mount *mp)
+{
+	__uint64_t resblks;
+
+	if (mp->m_resblks_save) {
+		resblks = mp->m_resblks_save;
+		mp->m_resblks_save = 0;
+	} else
+		resblks = xfs_default_resblks(mp);
+
+	xfs_reserve_blocks(mp, &resblks, NULL);
+}
+
 STATIC int
 xfs_fs_remount(
 	struct super_block	*sb,
@@ -1318,8 +1341,6 @@ xfs_fs_remount(
 
 	/* ro -> rw */
 	if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(*flags & MS_RDONLY)) {
-		__uint64_t resblks;
-
 		mp->m_flags &= ~XFS_MOUNT_RDONLY;
 		if (mp->m_flags & XFS_MOUNT_BARRIER)
 			xfs_mountfs_check_barriers(mp);
@@ -1342,15 +1363,7 @@ xfs_fs_remount(
 		 * Fill out the reserve pool if it is empty. Use the stashed
 		 * value if it is non-zero, otherwise go with the default.
 		 */
-		if (mp->m_resblks_save) {
-			resblks = mp->m_resblks_save;
-			mp->m_resblks_save = 0;
-		} else {
-			resblks = mp->m_sb.sb_dblocks;
-			do_div(resblks, 20);
-			resblks = min_t(__uint64_t, resblks, 1024);
-		}
-		xfs_reserve_blocks(mp, &resblks, NULL);
+		xfs_restore_resvblks(mp);
 	}
 
 	/* rw -> ro */
@@ -1363,11 +1376,9 @@ xfs_fs_remount(
 		 * so that if we get remounted rw, we can return it to the same
 		 * size.
 		 */
-		__uint64_t resblks = 0;
 
 		xfs_quiesce_data(mp);
-		mp->m_resblks_save = mp->m_resblks;
-		xfs_reserve_blocks(mp, &resblks, NULL);
+		xfs_save_resvblks(mp);
 		xfs_quiesce_attr(mp);
 		mp->m_flags |= XFS_MOUNT_RDONLY;
 	}
@@ -1386,10 +1397,21 @@ xfs_fs_freeze(
 {
 	struct xfs_mount	*mp = XFS_M(sb);
 
+	xfs_save_resvblks(mp);
 	xfs_quiesce_attr(mp);
 	return -xfs_fs_log_dummy(mp);
 }
 
+STATIC int
+xfs_fs_unfreeze(
+	struct super_block	*sb)
+{
+	struct xfs_mount	*mp = XFS_M(sb);
+
+	xfs_restore_resvblks(mp);
+	return 0;
+}
+
 STATIC int
 xfs_fs_show_options(
 	struct seq_file		*m,
@@ -1612,6 +1634,7 @@ static const struct super_operations xfs_super_operations = {
 	.put_super		= xfs_fs_put_super,
 	.sync_fs		= xfs_fs_sync_fs,
 	.freeze_fs		= xfs_fs_freeze,
+	.unfreeze_fs		= xfs_fs_unfreeze,
 	.statfs			= xfs_fs_statfs,
 	.remount_fs		= xfs_fs_remount,
 	.show_options		= xfs_fs_show_options,
-- 
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