9 files changed, 50 insertions, 33 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 79b4fa3b391d..c7e4163ede87 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -152,7 +152,8 @@ blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
         struct inode *inode = file->f_mapping->host;
 
         return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset,
-                                    blkdev_get_block, NULL, NULL, 0);
+                                    blkdev_get_block, NULL, NULL,
+                                    DIO_SKIP_DIO_COUNT);
 }
 
 int __sync_blockdev(struct block_device *bdev, int wait)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 811576346a92..9b774a0c9ca6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8129,7 +8129,7 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
         if (check_direct_IO(BTRFS_I(inode)->root, iocb, iter, offset))
                 return 0;
 
-        atomic_inc(&inode->i_dio_count);
+        inode_dio_begin(inode);
         smp_mb__after_atomic();
 
         /*
@@ -8169,7 +8169,7 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
                 current->journal_info = &outstanding_extents;
         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
                                      &BTRFS_I(inode)->runtime_flags)) {
-                inode_dio_done(inode);
+                inode_dio_end(inode);
                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
                 wakeup = false;
         }
@@ -8188,7 +8188,7 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
         }
 out:
         if (wakeup)
-                inode_dio_done(inode);
+                inode_dio_end(inode);
         if (relock)
                 mutex_lock(&inode->i_mutex);
 
diff --git a/fs/dax.c b/fs/dax.c
index a27846946525..cdde2b354e47 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -209,7 +209,7 @@ ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode,
         }
 
         /* Protects against truncate */
-        atomic_inc(&inode->i_dio_count);
+        inode_dio_begin(inode);
 
         retval = dax_io(inode, iter, pos, end, get_block, &bh);
 
@@ -219,7 +219,7 @@ ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode,
         if ((retval > 0) && end_io)
                 end_io(iocb, pos, retval, bh.b_private);
 
-        inode_dio_done(inode);
+        inode_dio_end(inode);
  out:
         return retval;
 }
diff --git a/fs/direct-io.c b/fs/direct-io.c
index c3b560b24a46..745d2342651a 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -253,7 +253,9 @@ static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret,
         if (dio->end_io && dio->result)
                 dio->end_io(dio->iocb, offset, transferred, dio->private);
 
-        inode_dio_done(dio->inode);
+        if (!(dio->flags & DIO_SKIP_DIO_COUNT))
+                inode_dio_end(dio->inode);
+
         if (is_async) {
                 if (dio->rw & WRITE) {
                         int err;
@@ -1195,7 +1197,8 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
         /*
          * Will be decremented at I/O completion time.
          */
-        atomic_inc(&inode->i_dio_count);
+        if (!(dio->flags & DIO_SKIP_DIO_COUNT))
+                inode_dio_begin(inode);
 
         retval = 0;
         sdio.blkbits = blkbits;
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 3580629e42d3..958824019509 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -682,11 +682,11 @@ retry:
                  * via ext4_inode_block_unlocked_dio(). Check inode's state
                  * while holding extra i_dio_count ref.
                  */
-                atomic_inc(&inode->i_dio_count);
+                inode_dio_begin(inode);
                 smp_mb();
                 if (unlikely(ext4_test_inode_state(inode,
                                                     EXT4_STATE_DIOREAD_LOCK))) {
-                        inode_dio_done(inode);
+                        inode_dio_end(inode);
                         goto locked;
                 }
                 if (IS_DAX(inode))
@@ -697,7 +697,7 @@ retry:
                                                    inode->i_sb->s_bdev, iter,
                                                    offset, ext4_get_block, NULL,
                                                    NULL, 0);
-                inode_dio_done(inode);
+                inode_dio_end(inode);
         } else {
 locked:
                 if (IS_DAX(inode))
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 063052e4aa8b..bccec41fb94b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2977,7 +2977,7 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
          * overwrite DIO as i_dio_count needs to be incremented under i_mutex.
          */
         if (iov_iter_rw(iter) == WRITE)
-                atomic_inc(&inode->i_dio_count);
+                inode_dio_begin(inode);
 
         /* If we do a overwrite dio, i_mutex locking can be released */
         overwrite = *((int *)iocb->private);
@@ -3079,7 +3079,7 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 
 retake_lock:
         if (iov_iter_rw(iter) == WRITE)
-                inode_dio_done(inode);
+                inode_dio_end(inode);
         /* take i_mutex locking again if we do a ovewrite dio */
         if (overwrite) {
                 up_read(&EXT4_I(inode)->i_data_sem);
diff --git a/fs/inode.c b/fs/inode.c
index 94886f9fbb06..ea37cd17b53f 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1946,20 +1946,6 @@ void inode_dio_wait(struct inode *inode)
 EXPORT_SYMBOL(inode_dio_wait);
 
 /*
- * inode_dio_done - signal finish of a direct I/O requests
- * @inode: inode the direct I/O happens on
- *
- * This is called once we've finished processing a direct I/O request,
- * and is used to wake up callers waiting for direct I/O to be quiesced.
- */
-void inode_dio_done(struct inode *inode)
-{
-        if (atomic_dec_and_test(&inode->i_dio_count))
-                wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
-}
-EXPORT_SYMBOL(inode_dio_done);
-
-/*
  * inode_set_flags - atomically set some inode flags
  *
  * Note: the caller should be holding i_mutex, or else be sure that
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index ed0e6031be88..b2cbc3a6cdd9 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -386,7 +386,7 @@ static void nfs_direct_complete(struct nfs_direct_req *dreq, bool write)
         if (write)
                 nfs_zap_mapping(inode, inode->i_mapping);
 
-        inode_dio_done(inode);
+        inode_dio_end(inode);
 
         if (dreq->iocb) {
                 long res = (long) dreq->error;
@@ -486,7 +486,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
                              &nfs_direct_read_completion_ops);
         get_dreq(dreq);
         desc.pg_dreq = dreq;
-        atomic_inc(&inode->i_dio_count);
+        inode_dio_begin(inode);
 
         while (iov_iter_count(iter)) {
                 struct page **pagevec;
@@ -538,7 +538,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
          * generic layer handle the completion.
          */
         if (requested_bytes == 0) {
-                inode_dio_done(inode);
+                inode_dio_end(inode);
                 nfs_direct_req_release(dreq);
                 return result < 0 ? result : -EIO;
         }
@@ -872,7 +872,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
                               &nfs_direct_write_completion_ops);
         desc.pg_dreq = dreq;
         get_dreq(dreq);
-        atomic_inc(&inode->i_dio_count);
+        inode_dio_begin(inode);
 
         NFS_I(inode)->write_io += iov_iter_count(iter);
         while (iov_iter_count(iter)) {
@@ -928,7 +928,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
          * generic layer handle the completion.
          */
         if (requested_bytes == 0) {
-                inode_dio_done(inode);
+                inode_dio_end(inode);
                 nfs_direct_req_release(dreq);
                 return result < 0 ? result : -EIO;
         }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b1d7db28c13c..9055eefa92c7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2635,6 +2635,9 @@ enum {
 
         /* filesystem can handle aio writes beyond i_size */
         DIO_ASYNC_EXTEND = 0x04,
+
+        /* inode/fs/bdev does not need truncate protection */
+        DIO_SKIP_DIO_COUNT = 0x08,
 };
 
 void dio_end_io(struct bio *bio, int error);
@@ -2657,7 +2660,31 @@ static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
 #endif
 
 void inode_dio_wait(struct inode *inode);
-void inode_dio_done(struct inode *inode);
+
+/*
+ * inode_dio_begin - signal start of a direct I/O requests
+ * @inode: inode the direct I/O happens on
+ *
+ * This is called once we've finished processing a direct I/O request,
+ * and is used to wake up callers waiting for direct I/O to be quiesced.
+ */
+static inline void inode_dio_begin(struct inode *inode)
+{
+        atomic_inc(&inode->i_dio_count);
+}
+
+/*
+ * inode_dio_end - signal finish of a direct I/O requests
+ * @inode: inode the direct I/O happens on
+ *
+ * This is called once we've finished processing a direct I/O request,
+ * and is used to wake up callers waiting for direct I/O to be quiesced.
+ */
+static inline void inode_dio_end(struct inode *inode)
+{
+        if (atomic_dec_and_test(&inode->i_dio_count))
+                wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
+}
 
 extern void inode_set_flags(struct inode *inode, unsigned int flags,
                             unsigned int mask);