[PATCH] convert ext3's truncate_sem to a mutex

ext3's truncate_sem is always released in the same function it's taken
and it otherwise is a mutex as well..
Signed-off-by: NArjan van de Ven <arjan@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

fs/ext3/file.c

@@ -37,9 +37,9 @@ static int ext3_release_file (struct inode * inode, struct file * filp)
 	if ((filp->f_mode & FMODE_WRITE) &&
 			(atomic_read(&inode->i_writecount) == 1))
 	{
-		down(&EXT3_I(inode)->truncate_sem);
+		mutex_lock(&EXT3_I(inode)->truncate_mutex);
 		ext3_discard_reservation(inode);
-		up(&EXT3_I(inode)->truncate_sem);
+		mutex_unlock(&EXT3_I(inode)->truncate_mutex);
 	}
 	if (is_dx(inode) && filp->private_data)
 		ext3_htree_free_dir_info(filp->private_data);

fs/ext3/inode.c

@@ -702,7 +702,7 @@ ext3_get_block_handle(handle_t *handle, struct inode *inode, sector_t iblock,
 	if (!create || err == -EIO)
 		goto cleanup;
 
-	down(&ei->truncate_sem);
+	mutex_lock(&ei->truncate_mutex);
 
 	/*
 	 * If the indirect block is missing while we are reading
@@ -723,7 +723,7 @@ ext3_get_block_handle(handle_t *handle, struct inode *inode, sector_t iblock,
 		}
 		partial = ext3_get_branch(inode, depth, offsets, chain, &err);
 		if (!partial) {
-			up(&ei->truncate_sem);
+			mutex_unlock(&ei->truncate_mutex);
 			if (err)
 				goto cleanup;
 			clear_buffer_new(bh_result);
@@ -759,13 +759,13 @@ ext3_get_block_handle(handle_t *handle, struct inode *inode, sector_t iblock,
 		err = ext3_splice_branch(handle, inode, iblock, chain,
 					 partial, left);
 	/*
-	 * i_disksize growing is protected by truncate_sem.  Don't forget to
+	 * i_disksize growing is protected by truncate_mutex.  Don't forget to
 	 * protect it if you're about to implement concurrent
 	 * ext3_get_block() -bzzz
 	*/
 	if (!err && extend_disksize && inode->i_size > ei->i_disksize)
 		ei->i_disksize = inode->i_size;
-	up(&ei->truncate_sem);
+	mutex_unlock(&ei->truncate_mutex);
 	if (err)
 		goto cleanup;
 
@@ -1227,7 +1227,7 @@ static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
  *	ext3_file_write() -> generic_file_write() -> __alloc_pages() -> ...
  *
  * Same applies to ext3_get_block().  We will deadlock on various things like
- * lock_journal and i_truncate_sem.
+ * lock_journal and i_truncate_mutex.
  *
  * Setting PF_MEMALLOC here doesn't work - too many internal memory
  * allocations fail.
@@ -2161,7 +2161,7 @@ void ext3_truncate(struct inode * inode)
 	 * From here we block out all ext3_get_block() callers who want to
 	 * modify the block allocation tree.
 	 */
-	down(&ei->truncate_sem);
+	mutex_lock(&ei->truncate_mutex);
 
 	if (n == 1) {		/* direct blocks */
 		ext3_free_data(handle, inode, NULL, i_data+offsets[0],
@@ -2228,7 +2228,7 @@ void ext3_truncate(struct inode * inode)
 
 	ext3_discard_reservation(inode);
 
-	up(&ei->truncate_sem);
+	mutex_unlock(&ei->truncate_mutex);
 	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
 	ext3_mark_inode_dirty(handle, inode);
 

fs/ext3/ioctl.c

@@ -182,7 +182,7 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
 		 * need to allocate reservation structure for this inode
 		 * before set the window size
 		 */
-		down(&ei->truncate_sem);
+		mutex_lock(&ei->truncate_mutex);
 		if (!ei->i_block_alloc_info)
 			ext3_init_block_alloc_info(inode);
 
@@ -190,7 +190,7 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
 			struct ext3_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
 			rsv->rsv_goal_size = rsv_window_size;
 		}
-		up(&ei->truncate_sem);
+		mutex_unlock(&ei->truncate_mutex);
 		return 0;
 	}
 	case EXT3_IOC_GROUP_EXTEND: {

fs/ext3/super.c

@@ -472,7 +472,7 @@ static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 #ifdef CONFIG_EXT3_FS_XATTR
 		init_rwsem(&ei->xattr_sem);
 #endif
-		init_MUTEX(&ei->truncate_sem);
+		mutex_init(&ei->truncate_mutex);
 		inode_init_once(&ei->vfs_inode);
 	}
 }

include/linux/ext3_fs_i.h

@@ -19,6 +19,7 @@
 #include <linux/rwsem.h>
 #include <linux/rbtree.h>
 #include <linux/seqlock.h>
+#include <linux/mutex.h>
 
 struct ext3_reserve_window {
 	__u32			_rsv_start;	/* First byte reserved */
@@ -122,16 +123,16 @@ struct ext3_inode_info {
 	__u16 i_extra_isize;
 
 	/*
-	 * truncate_sem is for serialising ext3_truncate() against
+	 * truncate_mutex is for serialising ext3_truncate() against
 	 * ext3_getblock().  In the 2.4 ext2 design, great chunks of inode's
 	 * data tree are chopped off during truncate. We can't do that in
 	 * ext3 because whenever we perform intermediate commits during
 	 * truncate, the inode and all the metadata blocks *must* be in a
 	 * consistent state which allows truncation of the orphans to restart
 	 * during recovery.  Hence we must fix the get_block-vs-truncate race
-	 * by other means, so we have truncate_sem.
+	 * by other means, so we have truncate_mutex.
 	 */
-	struct semaphore truncate_sem;
+	struct mutex truncate_mutex;
 	struct inode vfs_inode;
 };