Changeset a93d79a in mainline

Timestamp:

2010-10-19T21:11:11Z (14 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

8fb1bf82, e0e568ff

Parents:

f14291b

Message:

Do not hold the parent→idx→lock in when calling fat_idx_get_by_pos() as it
both is not necessary and violates the natural locking order used by
fat_idx_get_by_pos() and fat_idx_get_by_index().

File:

• uspace/srv/fs/fat/fat_ops.c (modified) (4 diffs)

uspace/srv/fs/fat/fat_ops.c

@@ -369 +369 @@
         unsigned blocks;
         fat_dentry_t *d;
+        dev_handle_t dev_handle;
         block_t *b;
         int rc;
 
         fibril_mutex_lock(&parentp->idx->lock);
-        bs = block_bb_get(parentp->idx->dev_handle);
+        dev_handle = parentp->idx->dev_handle;
+        fibril_mutex_unlock(&parentp->idx->lock);
+
+        bs = block_bb_get(dev_handle);
         blocks = parentp->size / BPS(bs);
         for (i = 0; i < blocks; i++) {
                 rc = fat_block_get(&b, bs, parentp, i, BLOCK_FLAGS_NONE);
-                if (rc != EOK) {
-                        fibril_mutex_unlock(&parentp->idx->lock);
+                if (rc != EOK)
                         return rc;
-                }
                 for (j = 0; j < DPS(bs); j++) { 
                         d = ((fat_dentry_t *)b->data) + j;
@@ -390 +392 @@
                                 /* miss */
                                 rc = block_put(b);
-                                fibril_mutex_unlock(&parentp->idx->lock);
                                 *rfn = NULL;
                                 return rc;
@@ -401 +402 @@
                                 /* hit */
                                 fat_node_t *nodep;
-                                /*
-                                 * Assume tree hierarchy for locking.  We
-                                 * already have the parent and now we are going
-                                 * to lock the child.  Never lock in the oposite
-                                 * order.
-                                 */
-                                fat_idx_t *idx = fat_idx_get_by_pos(
-                                    parentp->idx->dev_handle, parentp->firstc,
-                                    i * DPS(bs) + j);
-                                fibril_mutex_unlock(&parentp->idx->lock);
+                                fat_idx_t *idx = fat_idx_get_by_pos(dev_handle,
+                                    parentp->firstc, i * DPS(bs) + j);
                                 if (!idx) {
                                         /*
@@ -433 +426 @@
                 }
                 rc = block_put(b);
-                if (rc != EOK) {
-                        fibril_mutex_unlock(&parentp->idx->lock);
+                if (rc != EOK)
                         return rc;
-                }
-        }
-
-        fibril_mutex_unlock(&parentp->idx->lock);
+        }
+
         *rfn = NULL;
         return EOK;