fs: pull inode->i_lock up out of writeback_single_inode
First thing we do in writeback_single_inode() is take the i_lock and
the last thing we do is drop it. A caller already holds the i_lock,
so pull the i_lock out of writeback_single_inode() to reduce the
round trips on this lock during inode writeback.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index ed80065..b5ed541 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -332,9 +332,9 @@
}
/*
- * Write out an inode's dirty pages. Called under inode_wb_list_lock. Either
- * the caller has an active reference on the inode or the inode has I_WILL_FREE
- * set.
+ * Write out an inode's dirty pages. Called under inode_wb_list_lock and
+ * inode->i_lock. Either the caller has an active reference on the inode or
+ * the inode has I_WILL_FREE set.
*
* If `wait' is set, wait on the writeout.
*
@@ -349,7 +349,9 @@
unsigned dirty;
int ret;
- spin_lock(&inode->i_lock);
+ assert_spin_locked(&inode_wb_list_lock);
+ assert_spin_locked(&inode->i_lock);
+
if (!atomic_read(&inode->i_count))
WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
else
@@ -365,7 +367,6 @@
* completed a full scan of b_io.
*/
if (wbc->sync_mode != WB_SYNC_ALL) {
- spin_unlock(&inode->i_lock);
requeue_io(inode);
return 0;
}
@@ -456,7 +457,6 @@
}
}
inode_sync_complete(inode);
- spin_unlock(&inode->i_lock);
return ret;
}
@@ -544,7 +544,6 @@
}
__iget(inode);
- spin_unlock(&inode->i_lock);
pages_skipped = wbc->pages_skipped;
writeback_single_inode(inode, wbc);
@@ -555,6 +554,7 @@
*/
redirty_tail(inode);
}
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_wb_list_lock);
iput(inode);
cond_resched();
@@ -1309,7 +1309,9 @@
might_sleep();
spin_lock(&inode_wb_list_lock);
+ spin_lock(&inode->i_lock);
ret = writeback_single_inode(inode, &wbc);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_wb_list_lock);
if (sync)
inode_sync_wait(inode);
@@ -1333,7 +1335,9 @@
int ret;
spin_lock(&inode_wb_list_lock);
+ spin_lock(&inode->i_lock);
ret = writeback_single_inode(inode, wbc);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_wb_list_lock);
return ret;
}