X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=fs%2Fdirect-io.c;h=30dbbd1df51191a68d536ca430fad8001a80c39f;hb=a255a7456d4051e804fd6efff9a7c0f43483a7fc;hp=5a674a0c71461d4b5c5bcf05f42e867f196e4984;hpb=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2;p=powerpc.git

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 5a674a0c71..30dbbd1df5 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -56,7 +56,7 @@
  * lock_type is DIO_LOCKING for regular files on direct-IO-naive filesystems.
  * This determines whether we need to do the fancy locking which prevents
  * direct-IO from being able to read uninitialised disk blocks.  If its zero
- * (blockdev) this locking is not done, and if it is DIO_OWN_LOCKING i_sem is
+ * (blockdev) this locking is not done, and if it is DIO_OWN_LOCKING i_mutex is
  * not held for the entire direct write (taken briefly, initially, during a
  * direct read though, but its never held for the duration of a direct-IO).
  */
@@ -66,6 +66,7 @@ struct dio {
 	struct bio *bio;		/* bio under assembly */
 	struct inode *inode;
 	int rw;
+	loff_t i_size;			/* i_size when submitted */
 	int lock_type;			/* doesn't change */
 	unsigned blkbits;		/* doesn't change */
 	unsigned blkfactor;		/* When we're using an alignment which
@@ -161,6 +162,7 @@ static int dio_refill_pages(struct dio *dio)
 	up_read(&current->mm->mmap_sem);
 
 	if (ret < 0 && dio->blocks_available && (dio->rw == WRITE)) {
+		struct page *page = ZERO_PAGE(dio->curr_user_address);
 		/*
 		 * A memory fault, but the filesystem has some outstanding
 		 * mapped blocks.  We need to use those blocks up to avoid
@@ -168,7 +170,8 @@ static int dio_refill_pages(struct dio *dio)
 		 */
 		if (dio->page_errors == 0)
 			dio->page_errors = ret;
-		dio->pages[0] = ZERO_PAGE(dio->curr_user_address);
+		page_cache_get(page);
+		dio->pages[0] = page;
 		dio->head = 0;
 		dio->tail = 1;
 		ret = 0;
@@ -214,7 +217,7 @@ static struct page *dio_get_page(struct dio *dio)
 static void dio_complete(struct dio *dio, loff_t offset, ssize_t bytes)
 {
 	if (dio->end_io && dio->result)
-		dio->end_io(dio->inode, offset, bytes, dio->map_bh.b_private);
+		dio->end_io(dio->iocb, offset, bytes, dio->map_bh.b_private);
 	if (dio->lock_type == DIO_LOCKING)
 		up_read(&dio->inode->i_alloc_sem);
 }
@@ -230,17 +233,29 @@ static void finished_one_bio(struct dio *dio)
 	spin_lock_irqsave(&dio->bio_lock, flags);
 	if (dio->bio_count == 1) {
 		if (dio->is_async) {
+			ssize_t transferred;
+			loff_t offset;
+
 			/*
 			 * Last reference to the dio is going away.
 			 * Drop spinlock and complete the DIO.
 			 */
 			spin_unlock_irqrestore(&dio->bio_lock, flags);
-			dio_complete(dio, dio->block_in_file << dio->blkbits,
-					dio->result);
+
+			/* Check for short read case */
+			transferred = dio->result;
+			offset = dio->iocb->ki_pos;
+
+			if ((dio->rw == READ) &&
+			    ((offset + transferred) > dio->i_size))
+				transferred = dio->i_size - offset;
+
+			dio_complete(dio, offset, transferred);
+
 			/* Complete AIO later if falling back to buffered i/o */
 			if (dio->result == dio->size ||
 				((dio->rw == READ) && dio->result)) {
-				aio_complete(dio->iocb, dio->result, 0);
+				aio_complete(dio->iocb, transferred, 0);
 				kfree(dio);
 				return;
 			} else {
@@ -915,7 +930,7 @@ out:
 }
 
 /*
- * Releases both i_sem and i_alloc_sem
+ * Releases both i_mutex and i_alloc_sem
  */
 static ssize_t
 direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, 
@@ -951,6 +966,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
 	dio->page_errors = 0;
 	dio->result = 0;
 	dio->iocb = iocb;
+	dio->i_size = i_size_read(inode);
 
 	/*
 	 * BIO completion state.
@@ -1046,11 +1062,11 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
 
 	/*
 	 * All block lookups have been performed. For READ requests
-	 * we can let i_sem go now that its achieved its purpose
+	 * we can let i_mutex go now that its achieved its purpose
 	 * of protecting us from looking up uninitialized blocks.
 	 */
 	if ((rw == READ) && (dio->lock_type == DIO_LOCKING))
-		up(&dio->inode->i_sem);
+		mutex_unlock(&dio->inode->i_mutex);
 
 	/*
 	 * OK, all BIOs are submitted, so we can decrement bio_count to truly
@@ -1129,18 +1145,18 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
  * The locking rules are governed by the dio_lock_type parameter.
  *
  * DIO_NO_LOCKING (no locking, for raw block device access)
- * For writes, i_sem is not held on entry; it is never taken.
+ * For writes, i_mutex is not held on entry; it is never taken.
  *
  * DIO_LOCKING (simple locking for regular files)
- * For writes we are called under i_sem and return with i_sem held, even though
+ * For writes we are called under i_mutex and return with i_mutex held, even though
  * it is internally dropped.
- * For reads, i_sem is not held on entry, but it is taken and dropped before
+ * For reads, i_mutex is not held on entry, but it is taken and dropped before
  * returning.
  *
  * DIO_OWN_LOCKING (filesystem provides synchronisation and handling of
  *	uninitialised data, allowing parallel direct readers and writers)
- * For writes we are called without i_sem, return without it, never touch it.
- * For reads, i_sem is held on entry and will be released before returning.
+ * For writes we are called without i_mutex, return without it, never touch it.
+ * For reads, i_mutex is held on entry and will be released before returning.
  *
  * Additional i_alloc_sem locking requirements described inline below.
  */
@@ -1198,11 +1214,11 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	 * For block device access DIO_NO_LOCKING is used,
 	 *	neither readers nor writers do any locking at all
 	 * For regular files using DIO_LOCKING,
-	 *	readers need to grab i_sem and i_alloc_sem
-	 *	writers need to grab i_alloc_sem only (i_sem is already held)
+	 *	readers need to grab i_mutex and i_alloc_sem
+	 *	writers need to grab i_alloc_sem only (i_mutex is already held)
 	 * For regular files using DIO_OWN_LOCKING,
 	 *	neither readers nor writers take any locks here
-	 *	(i_sem is already held and release for writers here)
+	 *	(i_mutex is already held and release for writers here)
 	 */
 	dio->lock_type = dio_lock_type;
 	if (dio_lock_type != DIO_NO_LOCKING) {
@@ -1212,7 +1228,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 
 			mapping = iocb->ki_filp->f_mapping;
 			if (dio_lock_type != DIO_OWN_LOCKING) {
-				down(&inode->i_sem);
+				mutex_lock(&inode->i_mutex);
 				reader_with_isem = 1;
 			}
 
@@ -1224,7 +1240,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 			}
 
 			if (dio_lock_type == DIO_OWN_LOCKING) {
-				up(&inode->i_sem);
+				mutex_unlock(&inode->i_mutex);
 				reader_with_isem = 0;
 			}
 		}
@@ -1250,7 +1266,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 
 out:
 	if (reader_with_isem)
-		up(&inode->i_sem);
+		mutex_unlock(&inode->i_mutex);
 	if (rw & WRITE)
 		current->flags &= ~PF_SYNCWRITE;
 	return retval;