xfs: cleanup uuid handling

The uuid table handling should not be part of a semi-generic uuid library
but in the XFS code using it, so move those bits to xfs_mount.c and
refactor the whole glob to make it a proper abstraction.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Felix Blyakher <felixb@sgi.com>

1 files changed, 83 insertions, 41 deletions

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 92fedfcc879..b101990df02 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -45,7 +45,6 @@
 #include "xfs_fsops.h"
 #include "xfs_utils.h"
 
-STATIC int	xfs_uuid_mount(xfs_mount_t *);
 STATIC void	xfs_unmountfs_wait(xfs_mount_t *);
 
 
@@ -121,6 +120,84 @@ static const struct {
     { sizeof(xfs_sb_t),			 0 }
 };
 
+static DEFINE_MUTEX(xfs_uuid_table_mutex);
+static int xfs_uuid_table_size;
+static uuid_t *xfs_uuid_table;
+
+/*
+ * See if the UUID is unique among mounted XFS filesystems.
+ * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
+ */
+STATIC int
+xfs_uuid_mount(
+	struct xfs_mount	*mp)
+{
+	uuid_t			*uuid = &mp->m_sb.sb_uuid;
+	int			hole, i;
+
+	if (mp->m_flags & XFS_MOUNT_NOUUID)
+		return 0;
+
+	if (uuid_is_nil(uuid)) {
+		cmn_err(CE_WARN,
+			"XFS: Filesystem %s has nil UUID - can't mount",
+			mp->m_fsname);
+		return XFS_ERROR(EINVAL);
+	}
+
+	mutex_lock(&xfs_uuid_table_mutex);
+	for (i = 0, hole = -1; i < xfs_uuid_table_size; i++) {
+		if (uuid_is_nil(&xfs_uuid_table[i])) {
+			hole = i;
+			continue;
+		}
+		if (uuid_equal(uuid, &xfs_uuid_table[i]))
+			goto out_duplicate;
+	}
+
+	if (hole < 0) {
+		xfs_uuid_table = kmem_realloc(xfs_uuid_table,
+			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
+			xfs_uuid_table_size  * sizeof(*xfs_uuid_table),
+			KM_SLEEP);
+		hole = xfs_uuid_table_size++;
+	}
+	xfs_uuid_table[hole] = *uuid;
+	mutex_unlock(&xfs_uuid_table_mutex);
+
+	return 0;
+
+ out_duplicate:
+	mutex_unlock(&xfs_uuid_table_mutex);
+	cmn_err(CE_WARN, "XFS: Filesystem %s has duplicate UUID - can't mount",
+			 mp->m_fsname);
+	return XFS_ERROR(EINVAL);
+}
+
+STATIC void
+xfs_uuid_unmount(
+	struct xfs_mount	*mp)
+{
+	uuid_t			*uuid = &mp->m_sb.sb_uuid;
+	int			i;
+
+	if (mp->m_flags & XFS_MOUNT_NOUUID)
+		return;
+
+	mutex_lock(&xfs_uuid_table_mutex);
+	for (i = 0; i < xfs_uuid_table_size; i++) {
+		if (uuid_is_nil(&xfs_uuid_table[i]))
+			continue;
+		if (!uuid_equal(uuid, &xfs_uuid_table[i]))
+			continue;
+		memset(&xfs_uuid_table[i], 0, sizeof(uuid_t));
+		break;
+	}
+	ASSERT(i < xfs_uuid_table_size);
+	mutex_unlock(&xfs_uuid_table_mutex);
+}
+
+
 /*
  * Free up the resources associated with a mount structure.  Assume that
  * the structure was initially zeroed, so we can tell which fields got
@@ -962,18 +1039,9 @@ xfs_mountfs(
 
 	mp->m_maxioffset = xfs_max_file_offset(sbp->sb_blocklog);
 
-	/*
-	 * XFS uses the uuid from the superblock as the unique
-	 * identifier for fsid.  We can not use the uuid from the volume
-	 * since a single partition filesystem is identical to a single
-	 * partition volume/filesystem.
-	 */
-	if (!(mp->m_flags & XFS_MOUNT_NOUUID)) {
-		if (xfs_uuid_mount(mp)) {
-			error = XFS_ERROR(EINVAL);
-			goto out;
-		}
-	}
+	error = xfs_uuid_mount(mp);
+	if (error)
+		goto out;
 
 	/*
 	 * Set the minimum read and write sizes
@@ -1192,8 +1260,7 @@ xfs_mountfs(
  out_free_perag:
 	xfs_free_perag(mp);
  out_remove_uuid:
-	if (!(mp->m_flags & XFS_MOUNT_NOUUID))
-		uuid_table_remove(&mp->m_sb.sb_uuid);
+	xfs_uuid_unmount(mp);
  out:
 	return error;
 }
@@ -1276,9 +1343,7 @@ xfs_unmountfs(
 	xfs_unmountfs_wait(mp); 		/* wait for async bufs */
 	xfs_log_unmount_write(mp);
 	xfs_log_unmount(mp);
-
-	if ((mp->m_flags & XFS_MOUNT_NOUUID) == 0)
-		uuid_table_remove(&mp->m_sb.sb_uuid);
+	xfs_uuid_unmount(mp);
 
 #if defined(DEBUG)
 	xfs_errortag_clearall(mp, 0);
@@ -1780,29 +1845,6 @@ xfs_freesb(
 }
 
 /*
- * See if the UUID is unique among mounted XFS filesystems.
- * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
- */
-STATIC int
-xfs_uuid_mount(
-	xfs_mount_t	*mp)
-{
-	if (uuid_is_nil(&mp->m_sb.sb_uuid)) {
-		cmn_err(CE_WARN,
-			"XFS: Filesystem %s has nil UUID - can't mount",
-			mp->m_fsname);
-		return -1;
-	}
-	if (!uuid_table_insert(&mp->m_sb.sb_uuid)) {
-		cmn_err(CE_WARN,
-			"XFS: Filesystem %s has duplicate UUID - can't mount",
-			mp->m_fsname);
-		return -1;
-	}
-	return 0;
-}
-
-/*
  * Used to log changes to the superblock unit and width fields which could
  * be altered by the mount options, as well as any potential sb_features2
  * fixup. Only the first superblock is updated.