writeback: Move clearing of I_SYNC into inode_sync_complete()

Move clearing of I_SYNC into inode_sync_complete().  It is more logical to have
clearing of I_SYNC bit and waking of waiters in one place. Also later we will
have two places needing to clear I_SYNC and wake up waiters so this allows them
to use the common helper. Moving of I_SYNC clearing to a later stage of
writeback_single_inode() is safe since we hold i_lock all the time.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 539f36c..dd41437 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -231,11 +231,8 @@ static void requeue_io(struct inode *inode, struct bdi_writeback *wb)
 
 static void inode_sync_complete(struct inode *inode)
 {
-       /*
-        * Prevent speculative execution through
-        * spin_unlock(&wb->list_lock);
-        */
-
+       inode->i_state &= ~I_SYNC;
+       /* Waiters must see I_SYNC cleared before being woken up */
        smp_mb();
        wake_up_bit(&inode->i_state, __I_SYNC);
 }
@@ -436,7 +433,6 @@ writeback_single_inode(struct inode *inode, struct bdi_writeback *wb,
 
        spin_lock(&wb->list_lock);
        spin_lock(&inode->i_lock);
-       inode->i_state &= ~I_SYNC;
        if (!(inode->i_state & I_FREEING)) {
                /*
                 * Sync livelock prevention. Each inode is tagged and synced in