clean up lafs_erase_dblock

- remove some dead code
- make it work for blocks that don't have a parent
- simplify the call from lafs_invalidate_page
- general clean up

diff --git a/block.c b/block.c
index 69f46d1748a4d4e6689196826079ba87e9da591a..45a20291ced244603d1fdc8974b357a48eb02159 100644 (file)
--- a/block.c
+++ b/block.c
@@ -170,13 +170,11 @@ void lafs_invalidate_page(struct page *page, unsigned long offset)
                 *   wait for any pending IO to complete (so page can be freed)
                 */
                for (i=0; i<(1<<bits); i++) {
-                       if (start >= size) {
-                               if (test_bit(B_Dirty, &b[i].b.flags) ||
-                                   test_bit(B_Realloc, &b[i].b.flags) ||
-                                   test_bit(B_Uninc, &b[i].b.flags) ||
-                                   test_bit(B_PinPending, &b[i].b.flags))
-                                       lafs_erase_dblock(&b[i]);
-                       } else if (b_start >= offset) {
+                       if (start >= size)
+                               /* Remove block from mapping and file */
+                               lafs_erase_dblock(&b[i]);
+                       else if (b_start >= offset) {
+                               /* Just remove block from mapping */
                                lafs_iolock_block(&b[i].b);
                                BUG_ON(test_bit(B_Dirty, &b[i].b.flags));
                                BUG_ON(test_bit(B_Realloc, &b[i].b.flags));
@@ -480,41 +478,24 @@ void
 lafs_erase_dblock(struct datablock *b)
 {
        struct fs *fs = fs_from_inode(b->b.inode);
-       if (!b->b.parent) {
-               printk("erase with no parent: %s\n", strblk(&b->b));
-               BUG();
-               /* We have indirect ref on ->iblock so it can be de-refed */
-       }
+
        dprintk("Eraseblock for %s\n", strblk(&b->b));
        if (b->b.physaddr == 0 &&
            b->b.fileaddr == 0 &&
            LAFSI(b->b.inode)->depth == 0) {
-#if 0
-               /* This lives in the inode, so we cannot drop the
-                * block, we have to zero it.
-                */
-               char *buf = map_dblock(b);
-               memset(buf, 0, (1<<b->b.inode->i_blkbits));
-               unmap_dblock(b, buf);
-               return;
-#else
                /* We need to clear out the index block that this
                 * block lives in.
+                * Need private_lock to be allowed to dereference ->iblock
                 */
-               BUG_ON(LAFSI(b->b.inode)->depth != LAFSI(b->b.inode)->iblock->depth);
-               lafs_clear_index(LAFSI(b->b.inode)->iblock);
-               clear_bit(B_PhysValid, &b->b.flags);
-#endif
+               spin_lock(&b->b.inode->i_data.private_lock);
+               if (LAFSI(b->b.inode)->iblock) {
+                       BUG_ON(LAFSI(b->b.inode)->depth !=
+                              LAFSI(b->b.inode)->iblock->depth);
+                       lafs_clear_index(LAFSI(b->b.inode)->iblock);
+                       clear_bit(B_PhysValid, &b->b.flags);
+               }
+               spin_unlock(&b->b.inode->i_data.private_lock);
        }
-#if 0
-       /* We aren't dirtying the block, but we do need to write it,
-        * so moving ICredit to UnincCredit for consistency.
-        * It won't be needed, so maybe I shouldn't need to bother?
-        */
-       if (!test_and_set_bit(B_UnincCredit, &b->b.flags))
-               if (!test_and_clear_bit(B_ICredit, &b->b.flags))
-                       BUG(); // ICredit should be set before we dirty a block.
-#endif
        lafs_iolock_block(&b->b);
 
        if (LAFSI(b->b.inode)->type == TypeInodeFile &&
@@ -549,12 +530,21 @@ lafs_erase_dblock(struct datablock *b)
        } else
                spin_unlock(&fs->lock);
 
-       if (b->b.physaddr)
+       if (b->b.parent == NULL)
+               /* Erasing a block that isn't in the indexing tree only
+                * happens when truncating and lafs_invalidate_page is called
+                * on some clean page.
+                * So we don't clear out physaddr here, but instead leave that
+                * to the core truncate code.
+                * Just remove B_PhysValid to avoid confusion.
+                */
+               clear_bit(B_PhysValid, &b->b.flags);
+       else if (b->b.physaddr)
                lafs_allocated_block(fs, &b->b, 0);
-       else {
+       else
                if (test_and_clear_bit(B_UnincCredit, &b->b.flags))
                        lafs_space_return(fs, 1);
-       }
+
        lafs_iounlock_block(&b->b, 0);
 }