Changeset 0ec862d in mainline

Timestamp:

2008-10-27T13:28:29Z (16 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

9f95a80

Parents:

cb682eb

Message:

Add FAT allocation futex.

File:

• uspace/srv/fs/fat/fat_fat.c (modified) (5 diffs)

uspace/srv/fs/fat/fat_fat.c

@@ -33 +33 @@
 /**
  * @file        fat_fat.c
- * @brief       Functions that manipulate the file allocation tables.
+ * @brief       Functions that manipulate the File Allocation Tables.
  */
 
@@ -45 +45 @@
 #include <align.h>
 #include <assert.h>
+#include <futex.h>
+
+/**
+ * The fat_alloc_lock futex protects all copies of the File Allocation Table
+ * during allocation of clusters. The lock does not have to be held durring
+ * deallocation of clusters.
+ */  
+static futex_t fat_alloc_lock = FUTEX_INITIALIZER;
 
 block_t *
@@ -261 +269 @@
          * Search FAT1 for unused clusters.
          */
+        futex_down(&fat_alloc_lock);
         for (b = 0, cl = 0; b < sf; blk++) {
                 blk = block_get(dev_handle, rscnt + b, bps);
@@ -284 +293 @@
                                         *lcl = lifo[0];
                                         free(lifo);
+                                        futex_up(&fat_alloc_lock);
                                         return EOK;
                                 }
@@ -290 +300 @@
                 block_put(blk);
         }
+        futex_up(&fat_alloc_lock);
 
         /*