xfs: Use xarray to track SB UUIDs instead of plain array.

Removing the plain array to track the UUIDs and switch
to xarray makes it more readable.

Signed-off-by: Lukas Herbolt <lukas@herbolt.com>
[cem: remove unneeded return from xfs_uuid_unmount]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 9c295abd0a0acf66090ce54889c839b0a73f1fd7..265011333904d2155c8aa606d815bbe4e2fb78d0 100644 (file)
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -44,17 +44,36 @@
 #include "xfs_healthmon.h"
 
 static DEFINE_MUTEX(xfs_uuid_table_mutex);
-static int xfs_uuid_table_size;
-static uuid_t *xfs_uuid_table;
+static DEFINE_XARRAY_ALLOC(xfs_uuid_table);
+
+static uuid_t *
+xfs_uuid_search(
+       uuid_t          *new_uuid)
+{
+       unsigned long   index = 0;
+       uuid_t          *uuid;
+
+       xa_for_each(&xfs_uuid_table, index, uuid) {
+               if (uuid_equal(uuid, new_uuid))
+                       return uuid;
+       }
+       return NULL;
+}
+
+static void
+xfs_uuid_delete(
+       uuid_t          *uuid,
+       unsigned int    index)
+{
+       ASSERT(uuid_equal(xa_load(&xfs_uuid_table, index), uuid));
+       xa_erase(&xfs_uuid_table, index);
+}
 
 void
 xfs_uuid_table_free(void)
 {
-       if (xfs_uuid_table_size == 0)
-               return;
-       kfree(xfs_uuid_table);
-       xfs_uuid_table = NULL;
-       xfs_uuid_table_size = 0;
+       ASSERT(xa_empty(&xfs_uuid_table));
+       xa_destroy(&xfs_uuid_table);
 }
 
 /*
@@ -66,7 +85,7 @@ xfs_uuid_mount(
        struct xfs_mount        *mp)
 {
        uuid_t                  *uuid = &mp->m_sb.sb_uuid;
-       int                     hole, i;
+       int                     ret;
 
        /* Publish UUID in struct super_block */
        super_set_uuid(mp->m_super, uuid->b, sizeof(*uuid));
@@ -80,30 +99,17 @@ xfs_uuid_mount(
        }
 
        mutex_lock(&xfs_uuid_table_mutex);
-       for (i = 0, hole = -1; i < xfs_uuid_table_size; i++) {
-               if (uuid_is_null(&xfs_uuid_table[i])) {
-                       hole = i;
-                       continue;
-               }
-               if (uuid_equal(uuid, &xfs_uuid_table[i]))
-                       goto out_duplicate;
-       }
-
-       if (hole < 0) {
-               xfs_uuid_table = krealloc(xfs_uuid_table,
-                       (xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
-                       GFP_KERNEL | __GFP_NOFAIL);
-               hole = xfs_uuid_table_size++;
+       if (unlikely(xfs_uuid_search(uuid))) {
+               xfs_warn(mp, "Filesystem has duplicate UUID %pU - can't mount",
+                               uuid);
+               mutex_unlock(&xfs_uuid_table_mutex);
+               return -EINVAL;
        }
-       xfs_uuid_table[hole] = *uuid;
-       mutex_unlock(&xfs_uuid_table_mutex);
 
-       return 0;
-
- out_duplicate:
+       ret = xa_alloc(&xfs_uuid_table, &mp->m_uuid_table_index, uuid,
+                               xa_limit_32b, GFP_KERNEL);
        mutex_unlock(&xfs_uuid_table_mutex);
-       xfs_warn(mp, "Filesystem has duplicate UUID %pU - can't mount", uuid);
-       return -EINVAL;
+       return ret;
 }
 
 STATIC void
@@ -111,21 +117,12 @@ xfs_uuid_unmount(
        struct xfs_mount        *mp)
 {
        uuid_t                  *uuid = &mp->m_sb.sb_uuid;
-       int                     i;
 
        if (xfs_has_nouuid(mp))
                return;
 
        mutex_lock(&xfs_uuid_table_mutex);
-       for (i = 0; i < xfs_uuid_table_size; i++) {
-               if (uuid_is_null(&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);
+       xfs_uuid_delete(uuid, mp->m_uuid_table_index);
        mutex_unlock(&xfs_uuid_table_mutex);
 }
 

diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index ddd4028be8d6bac3e4fae48e036b50387917cbe5..d964bae096ef6fc5893fdc4511901e63a160ded1 100644 (file)
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -346,6 +346,9 @@ typedef struct xfs_mount {
 
        /* Private data referring to a health monitor object. */
        struct xfs_healthmon __rcu      *m_healthmon;
+
+       /* Index of uuid record in the uuid xarray. */
+       unsigned int            m_uuid_table_index;
 } xfs_mount_t;
 
 #define M_IGEO(mp)             (&(mp)->m_ino_geo)