1 files changed, 91 insertions, 50 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 59c6e4956786..b5ed541fb137 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -176,6 +176,17 @@ void bdi_start_background_writeback(struct backing_dev_info *bdi)
 }
 
 /*
+ * Remove the inode from the writeback list it is on.
+ */
+void inode_wb_list_del(struct inode *inode)
+{
+        spin_lock(&inode_wb_list_lock);
+        list_del_init(&inode->i_wb_list);
+        spin_unlock(&inode_wb_list_lock);
+}
+
+
+/*
  * Redirty an inode: set its when-it-was dirtied timestamp and move it to the
  * furthest end of its superblock's dirty-inode list.
  *
@@ -188,6 +199,7 @@ static void redirty_tail(struct inode *inode)
 {
         struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
 
+        assert_spin_locked(&inode_wb_list_lock);
         if (!list_empty(&wb->b_dirty)) {
                 struct inode *tail;
 
@@ -205,14 +217,17 @@ static void requeue_io(struct inode *inode)
 {
         struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
 
+        assert_spin_locked(&inode_wb_list_lock);
         list_move(&inode->i_wb_list, &wb->b_more_io);
 }
 
 static void inode_sync_complete(struct inode *inode)
 {
         /*
-         * Prevent speculative execution through spin_unlock(&inode_lock);
+         * Prevent speculative execution through
+         * spin_unlock(&inode_wb_list_lock);
          */
+
         smp_mb();
         wake_up_bit(&inode->i_state, __I_SYNC);
 }
@@ -286,6 +301,7 @@ static void move_expired_inodes(struct list_head *delaying_queue,
  */
 static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
 {
+        assert_spin_locked(&inode_wb_list_lock);
         list_splice_init(&wb->b_more_io, &wb->b_io);
         move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
 }
@@ -306,25 +322,25 @@ static void inode_wait_for_writeback(struct inode *inode)
         wait_queue_head_t *wqh;
 
         wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
-         while (inode->i_state & I_SYNC) {
-                spin_unlock(&inode_lock);
+        while (inode->i_state & I_SYNC) {
+                spin_unlock(&inode->i_lock);
+                spin_unlock(&inode_wb_list_lock);
                 __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
-                spin_lock(&inode_lock);
+                spin_lock(&inode_wb_list_lock);
+                spin_lock(&inode->i_lock);
         }
 }
 
 /*
- * Write out an inode's dirty pages.  Called under inode_lock.  Either the
- * caller has ref on the inode (either via __iget or via syscall against an fd)
- * or the inode has I_WILL_FREE set (via generic_forget_inode)
+ * 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.
  *
  * The whole writeout design is quite complex and fragile.  We want to avoid
  * starvation of particular inodes when others are being redirtied, prevent
  * livelocks, etc.
- *
- * Called under inode_lock.
  */
 static int
 writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
@@ -333,6 +349,9 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
         unsigned dirty;
         int ret;
 
+        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
@@ -363,7 +382,8 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
         /* Set I_SYNC, reset I_DIRTY_PAGES */
         inode->i_state |= I_SYNC;
         inode->i_state &= ~I_DIRTY_PAGES;
-        spin_unlock(&inode_lock);
+        spin_unlock(&inode->i_lock);
+        spin_unlock(&inode_wb_list_lock);
 
         ret = do_writepages(mapping, wbc);
 
@@ -383,10 +403,10 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
          * due to delalloc, clear dirty metadata flags right before
          * write_inode()
          */
-        spin_lock(&inode_lock);
+        spin_lock(&inode->i_lock);
         dirty = inode->i_state & I_DIRTY;
         inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC);
-        spin_unlock(&inode_lock);
+        spin_unlock(&inode->i_lock);
         /* Don't write the inode if only I_DIRTY_PAGES was set */
         if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
                 int err = write_inode(inode, wbc);
@@ -394,7 +414,8 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
                         ret = err;
         }
 
-        spin_lock(&inode_lock);
+        spin_lock(&inode_wb_list_lock);
+        spin_lock(&inode->i_lock);
         inode->i_state &= ~I_SYNC;
         if (!(inode->i_state & I_FREEING)) {
                 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
@@ -506,7 +527,9 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
                  * kind does not need peridic writeout yet, and for the latter
                  * kind writeout is handled by the freer.
                  */
+                spin_lock(&inode->i_lock);
                 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
+                        spin_unlock(&inode->i_lock);
                         requeue_io(inode);
                         continue;
                 }
@@ -515,10 +538,13 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
                  * Was this inode dirtied after sync_sb_inodes was called?
                  * This keeps sync from extra jobs and livelock.
                  */
-                if (inode_dirtied_after(inode, wbc->wb_start))
+                if (inode_dirtied_after(inode, wbc->wb_start)) {
+                        spin_unlock(&inode->i_lock);
                         return 1;
+                }
 
                 __iget(inode);
+
                 pages_skipped = wbc->pages_skipped;
                 writeback_single_inode(inode, wbc);
                 if (wbc->pages_skipped != pages_skipped) {
@@ -528,10 +554,11 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
                          */
                         redirty_tail(inode);
                 }
-                spin_unlock(&inode_lock);
+                spin_unlock(&inode->i_lock);
+                spin_unlock(&inode_wb_list_lock);
                 iput(inode);
                 cond_resched();
-                spin_lock(&inode_lock);
+                spin_lock(&inode_wb_list_lock);
                 if (wbc->nr_to_write <= 0) {
                         wbc->more_io = 1;
                         return 1;
@@ -550,7 +577,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
 
         if (!wbc->wb_start)
                 wbc->wb_start = jiffies; /* livelock avoidance */
-        spin_lock(&inode_lock);
+        spin_lock(&inode_wb_list_lock);
         if (!wbc->for_kupdate || list_empty(&wb->b_io))
                 queue_io(wb, wbc->older_than_this);
 
@@ -568,7 +595,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
                 if (ret)
                         break;
         }
-        spin_unlock(&inode_lock);
+        spin_unlock(&inode_wb_list_lock);
         /* Leave any unwritten inodes on b_io */
 }
 
@@ -577,11 +604,11 @@ static void __writeback_inodes_sb(struct super_block *sb,
 {
         WARN_ON(!rwsem_is_locked(&sb->s_umount));
 
-        spin_lock(&inode_lock);
+        spin_lock(&inode_wb_list_lock);
         if (!wbc->for_kupdate || list_empty(&wb->b_io))
                 queue_io(wb, wbc->older_than_this);
         writeback_sb_inodes(sb, wb, wbc, true);
-        spin_unlock(&inode_lock);
+        spin_unlock(&inode_wb_list_lock);
 }
 
 /*
@@ -720,13 +747,15 @@ static long wb_writeback(struct bdi_writeback *wb,
                  * become available for writeback. Otherwise
                  * we'll just busyloop.
                  */
-                spin_lock(&inode_lock);
+                spin_lock(&inode_wb_list_lock);
                 if (!list_empty(&wb->b_more_io))  {
                         inode = wb_inode(wb->b_more_io.prev);
                         trace_wbc_writeback_wait(&wbc, wb->bdi);
+                        spin_lock(&inode->i_lock);
                         inode_wait_for_writeback(inode);
+                        spin_unlock(&inode->i_lock);
                 }
-                spin_unlock(&inode_lock);
+                spin_unlock(&inode_wb_list_lock);
         }
 
         return wrote;
@@ -992,7 +1021,6 @@ void __mark_inode_dirty(struct inode *inode, int flags)
 {
         struct super_block *sb = inode->i_sb;
         struct backing_dev_info *bdi = NULL;
-        bool wakeup_bdi = false;
 
         /*
          * Don't do this for I_DIRTY_PAGES - that doesn't actually
@@ -1016,7 +1044,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
         if (unlikely(block_dump))
                 block_dump___mark_inode_dirty(inode);
 
-        spin_lock(&inode_lock);
+        spin_lock(&inode->i_lock);
         if ((inode->i_state & flags) != flags) {
                 const int was_dirty = inode->i_state & I_DIRTY;
 
@@ -1028,7 +1056,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
                  * superblock list, based upon its state.
                  */
                 if (inode->i_state & I_SYNC)
-                        goto out;
+                        goto out_unlock_inode;
 
                 /*
                  * Only add valid (hashed) inodes to the superblock's
@@ -1036,16 +1064,17 @@ void __mark_inode_dirty(struct inode *inode, int flags)
                  */
                 if (!S_ISBLK(inode->i_mode)) {
                         if (inode_unhashed(inode))
-                                goto out;
+                                goto out_unlock_inode;
                 }
                 if (inode->i_state & I_FREEING)
-                        goto out;
+                        goto out_unlock_inode;
 
                 /*
                  * If the inode was already on b_dirty/b_io/b_more_io, don't
                  * reposition it (that would break b_dirty time-ordering).
                  */
                 if (!was_dirty) {
+                        bool wakeup_bdi = false;
                         bdi = inode_to_bdi(inode);
 
                         if (bdi_cap_writeback_dirty(bdi)) {
@@ -1062,15 +1091,20 @@ void __mark_inode_dirty(struct inode *inode, int flags)
                                         wakeup_bdi = true;
                         }
 
+                        spin_unlock(&inode->i_lock);
+                        spin_lock(&inode_wb_list_lock);
                         inode->dirtied_when = jiffies;
                         list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
+                        spin_unlock(&inode_wb_list_lock);
+
+                        if (wakeup_bdi)
+                                bdi_wakeup_thread_delayed(bdi);
+                        return;
                 }
         }
-out:
-        spin_unlock(&inode_lock);
+out_unlock_inode:
+        spin_unlock(&inode->i_lock);
 
-        if (wakeup_bdi)
-                bdi_wakeup_thread_delayed(bdi);
 }
 EXPORT_SYMBOL(__mark_inode_dirty);
 
@@ -1101,7 +1135,7 @@ static void wait_sb_inodes(struct super_block *sb)
          */
         WARN_ON(!rwsem_is_locked(&sb->s_umount));
 
-        spin_lock(&inode_lock);
+        spin_lock(&inode_sb_list_lock);
 
         /*
          * Data integrity sync. Must wait for all pages under writeback,
@@ -1111,22 +1145,25 @@ static void wait_sb_inodes(struct super_block *sb)
          * we still have to wait for that writeout.
          */
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-                struct address_space *mapping;
+                struct address_space *mapping = inode->i_mapping;
 
-                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
-                        continue;
-                mapping = inode->i_mapping;
-                if (mapping->nrpages == 0)
+                spin_lock(&inode->i_lock);
+                if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+                    (mapping->nrpages == 0)) {
+                        spin_unlock(&inode->i_lock);
                         continue;
+                }
                 __iget(inode);
-                spin_unlock(&inode_lock);
+                spin_unlock(&inode->i_lock);
+                spin_unlock(&inode_sb_list_lock);
+
                 /*
-                 * We hold a reference to 'inode' so it couldn't have
-                 * been removed from s_inodes list while we dropped the
-                 * inode_lock.  We cannot iput the inode now as we can
-                 * be holding the last reference and we cannot iput it
-                 * under inode_lock. So we keep the reference and iput
-                 * it later.
+                 * We hold a reference to 'inode' so it couldn't have been
+                 * removed from s_inodes list while we dropped the
+                 * inode_sb_list_lock.  We cannot iput the inode now as we can
+                 * be holding the last reference and we cannot iput it under
+                 * inode_sb_list_lock. So we keep the reference and iput it
+                 * later.
                  */
                 iput(old_inode);
                 old_inode = inode;
@@ -1135,9 +1172,9 @@ static void wait_sb_inodes(struct super_block *sb)
 
                 cond_resched();
 
-                spin_lock(&inode_lock);
+                spin_lock(&inode_sb_list_lock);
         }
-        spin_unlock(&inode_lock);
+        spin_unlock(&inode_sb_list_lock);
         iput(old_inode);
 }
 
@@ -1271,9 +1308,11 @@ int write_inode_now(struct inode *inode, int sync)
                 wbc.nr_to_write = 0;
 
         might_sleep();
-        spin_lock(&inode_lock);
+        spin_lock(&inode_wb_list_lock);
+        spin_lock(&inode->i_lock);
         ret = writeback_single_inode(inode, &wbc);
-        spin_unlock(&inode_lock);
+        spin_unlock(&inode->i_lock);
+        spin_unlock(&inode_wb_list_lock);
         if (sync)
                 inode_sync_wait(inode);
         return ret;
@@ -1295,9 +1334,11 @@ int sync_inode(struct inode *inode, struct writeback_control *wbc)
 {
         int ret;
 
-        spin_lock(&inode_lock);
+        spin_lock(&inode_wb_list_lock);
+        spin_lock(&inode->i_lock);
         ret = writeback_single_inode(inode, wbc);
-        spin_unlock(&inode_lock);
+        spin_unlock(&inode->i_lock);
+        spin_unlock(&inode_wb_list_lock);
         return ret;
 }
 EXPORT_SYMBOL(sync_inode);