fs: move code out of buffer.c

Move invalidate_bdev, block_sync_page into fs/block_dev.c.  Export
kill_bdev as well, so brd doesn't have to open code it.  Reduce
buffer_head.h requirement accordingly.

Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving.  The small comment replacing it says enough.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

28 files changed, 40 insertions, 83 deletions

diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
index ba42719..1c16141 100644
--- a/arch/powerpc/sysdev/axonram.c
+++ b/arch/powerpc/sysdev/axonram.c
@@ -25,7 +25,6 @@
 
 #include <linux/bio.h>
 #include <linux/blkdev.h>
-#include <linux/buffer_head.h>
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/fs.h>
diff --git a/block/genhd.c b/block/genhd.c
index bf443a7..b7d1a0e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -15,7 +15,6 @@
 #include <linux/slab.h>
 #include <linux/kmod.h>
 #include <linux/kobj_map.h>
-#include <linux/buffer_head.h>
 #include <linux/mutex.h>
 #include <linux/idr.h>
 #include <linux/log2.h>
diff --git a/block/ioctl.c b/block/ioctl.c
index ca939fc..91e7b19c 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -5,7 +5,7 @@
 #include <linux/blkpg.h>
 #include <linux/hdreg.h>
 #include <linux/backing-dev.h>
-#include <linux/buffer_head.h>
+#include <linux/fs.h>
 #include <linux/blktrace_api.h>
 #include <asm/uaccess.h>
 
diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c
index 8eba86b..386146d 100644
--- a/drivers/block/amiflop.c
+++ b/drivers/block/amiflop.c
@@ -63,7 +63,7 @@
 #include <linux/mutex.h>
 #include <linux/amifdreg.h>
 #include <linux/amifd.h>
-#include <linux/buffer_head.h>
+#include <linux/fs.h>
 #include <linux/blkdev.h>
 #include <linux/elevator.h>
 #include <linux/interrupt.h>
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index d22119d..ec24643 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -17,7 +17,7 @@
 #include <linux/highmem.h>
 #include <linux/mutex.h>
 #include <linux/radix-tree.h>
-#include <linux/buffer_head.h> /* invalidate_bh_lrus() */
+#include <linux/fs.h>
 #include <linux/slab.h>
 
 #include <asm/uaccess.h>
@@ -402,14 +402,13 @@ static int brd_ioctl(struct block_device *bdev, fmode_t mode,
 	error = -EBUSY;
 	if (bdev->bd_openers <= 1) {
 		/*
-		 * Invalidate the cache first, so it isn't written
-		 * back to the device.
+		 * Kill the cache first, so it isn't written back to the
+		 * device.
 		 *
 		 * Another thread might instantiate more buffercache here,
 		 * but there is not much we can do to close that race.
 		 */
-		invalidate_bh_lrus();
-		truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
+		kill_bdev(bdev);
 		brd_free_pages(brd);
 		error = 0;
 	}
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 9955a53..510fb10 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -188,7 +188,6 @@ static int print_unex = 1;
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/mod_devicetable.h>
-#include <linux/buffer_head.h>	/* for invalidate_buffers() */
 #include <linux/mutex.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 1e888c9..f002577 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -69,7 +69,6 @@
 #include <linux/freezer.h>
 #include <linux/mutex.h>
 #include <linux/writeback.h>
-#include <linux/buffer_head.h>		/* for invalidate_bdev() */
 #include <linux/completion.h>
 #include <linux/highmem.h>
 #include <linux/kthread.h>
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index f997c27..2118211 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -267,7 +267,6 @@
 
 #include <linux/module.h>
 #include <linux/fs.h>
-#include <linux/buffer_head.h>
 #include <linux/major.h>
 #include <linux/types.h>
 #include <linux/errno.h>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 4720f68..b89c548 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -14,7 +14,6 @@
 #include <linux/moduleparam.h>
 #include <linux/blkpg.h>
 #include <linux/bio.h>
-#include <linux/buffer_head.h>
 #include <linux/mempool.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index f47f1f8..5d1b676 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -36,8 +36,7 @@
 #include <linux/blkdev.h>
 #include <linux/sysctl.h>
 #include <linux/seq_file.h>
-#include <linux/mutex.h>
-#include <linux/buffer_head.h> /* for invalidate_bdev */
+#include <linux/fs.h>
 #include <linux/poll.h>
 #include <linux/ctype.h>
 #include <linux/string.h>
diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index b78f231..ebeabc7 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -14,7 +14,6 @@
 #include <linux/list.h>
 #include <linux/init.h>
 #include <linux/mtd/mtd.h>
-#include <linux/buffer_head.h>
 #include <linux/mutex.h>
 #include <linux/mount.h>
 #include <linux/slab.h>
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 65894f0..2de5b60 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -17,7 +17,6 @@
 #include <linux/ctype.h>
 #include <linux/major.h>
 #include <linux/slab.h>
-#include <linux/buffer_head.h>
 #include <linux/hdreg.h>
 #include <linux/async.h>
 #include <linux/mutex.h>
diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
index 6803b1e..92d24d6 100644
--- a/drivers/scsi/scsicam.c
+++ b/drivers/scsi/scsicam.c
@@ -16,7 +16,6 @@
 #include <linux/genhd.h>
 #include <linux/kernel.h>
 #include <linux/blkdev.h>
-#include <linux/buffer_head.h>
 #include <asm/unaligned.h>
 
 #include <scsi/scsicam.h>
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 43db715..7867b7c 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -32,7 +32,6 @@
 #include <linux/module.h>
 #include <linux/suspend.h>
 #include <linux/writeback.h>
-#include <linux/buffer_head.h>		/* for fsync_bdev() */
 #include <linux/swap.h>
 #include <linux/spinlock.h>
 #include <linux/vt_kern.h>
@@ -41,6 +40,7 @@
 #include <linux/oom.h>
 #include <linux/slab.h>
 #include <linux/input.h>
+#include <linux/uaccess.h>
 
 #include <asm/ptrace.h>
 #include <asm/irq_regs.h>
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 7866cdd..69a5b6f 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -17,6 +17,7 @@
 #include <linux/module.h>
 #include <linux/blkpg.h>
 #include <linux/buffer_head.h>
+#include <linux/swap.h>
 #include <linux/pagevec.h>
 #include <linux/writeback.h>
 #include <linux/mpage.h>
@@ -25,6 +26,7 @@
 #include <linux/namei.h>
 #include <linux/log2.h>
 #include <linux/kmemleak.h>
+#include <linux/cleancache.h>
 #include <asm/uaccess.h>
 #include "internal.h"
 
@@ -82,13 +84,35 @@ static sector_t max_block(struct block_device *bdev)
 }
 
 /* Kill _all_ buffers and pagecache , dirty or not.. */
-static void kill_bdev(struct block_device *bdev)
+void kill_bdev(struct block_device *bdev)
 {
-	if (bdev->bd_inode->i_mapping->nrpages == 0)
+	struct address_space *mapping = bdev->bd_inode->i_mapping;
+
+	if (mapping->nrpages == 0)
 		return;
+
 	invalidate_bh_lrus();
-	truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
+	truncate_inode_pages(mapping, 0);
 }	
+EXPORT_SYMBOL(kill_bdev);
+
+/* Invalidate clean unused buffers and pagecache. */
+void invalidate_bdev(struct block_device *bdev)
+{
+	struct address_space *mapping = bdev->bd_inode->i_mapping;
+
+	if (mapping->nrpages == 0)
+		return;
+
+	invalidate_bh_lrus();
+	lru_add_drain_all();	/* make sure all lru add caches are flushed */
+	invalidate_mapping_pages(mapping, 0, -1);
+	/* 99% of the time, we don't need to flush the cleancache on the bdev.
+	 * But, for the strange corners, lets be cautious
+	 */
+	cleancache_flush_inode(mapping);
+}
+EXPORT_SYMBOL(invalidate_bdev);
 
 int set_blocksize(struct block_device *bdev, int size)
 {
diff --git a/fs/buffer.c b/fs/buffer.c
index 19d8eb7..1a30db7 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -41,7 +41,6 @@
 #include <linux/bitops.h>
 #include <linux/mpage.h>
 #include <linux/bit_spinlock.h>
-#include <linux/cleancache.h>
 
 static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
 
@@ -231,55 +230,6 @@ out:
 	return ret;
 }
 
-/* If invalidate_buffers() will trash dirty buffers, it means some kind
-   of fs corruption is going on. Trashing dirty data always imply losing
-   information that was supposed to be just stored on the physical layer
-   by the user.
-
-   Thus invalidate_buffers in general usage is not allwowed to trash
-   dirty buffers. For example ioctl(FLSBLKBUF) expects dirty data to
-   be preserved.  These buffers are simply skipped.
-  
-   We also skip buffers which are still in use.  For example this can
-   happen if a userspace program is reading the block device.
-
-   NOTE: In the case where the user removed a removable-media-disk even if
-   there's still dirty data not synced on disk (due a bug in the device driver
-   or due an error of the user), by not destroying the dirty buffers we could
-   generate corruption also on the next media inserted, thus a parameter is
-   necessary to handle this case in the most safe way possible (trying
-   to not corrupt also the new disk inserted with the data belonging to
-   the old now corrupted disk). Also for the ramdisk the natural thing
-   to do in order to release the ramdisk memory is to destroy dirty buffers.
-
-   These are two special cases. Normal usage imply the device driver
-   to issue a sync on the device (without waiting I/O completion) and
-   then an invalidate_buffers call that doesn't trash dirty buffers.
-
-   For handling cache coherency with the blkdev pagecache the 'update' case
-   is been introduced. It is needed to re-read from disk any pinned
-   buffer. NOTE: re-reading from disk is destructive so we can do it only
-   when we assume nobody is changing the buffercache under our I/O and when
-   we think the disk contains more recent information than the buffercache.
-   The update == 1 pass marks the buffers we need to update, the update == 2
-   pass does the actual I/O. */
-void invalidate_bdev(struct block_device *bdev)
-{
-	struct address_space *mapping = bdev->bd_inode->i_mapping;
-
-	if (mapping->nrpages == 0)
-		return;
-
-	invalidate_bh_lrus();
-	lru_add_drain_all();	/* make sure all lru add caches are flushed */
-	invalidate_mapping_pages(mapping, 0, -1);
-	/* 99% of the time, we don't need to flush the cleancache on the bdev.
-	 * But, for the strange corners, lets be cautious
-	 */
-	cleancache_flush_inode(mapping);
-}
-EXPORT_SYMBOL(invalidate_bdev);
-
 /*
  * Kick the writeback threads then try to free up some ZONE_NORMAL memory.
  */
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 1064805..67bef6d 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -11,7 +11,6 @@
 
 #include <linux/slab.h>
 #include <linux/mount.h>
-#include <linux/buffer_head.h>
 #include "internal.h"
 
 #define list_to_page(head) (list_entry((head)->prev, struct page, lru))
diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index 739fb59..c37adb2 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -20,7 +20,6 @@
 #include <linux/cramfs_fs.h>
 #include <linux/slab.h>
 #include <linux/cramfs_fs_sb.h>
-#include <linux/buffer_head.h>
 #include <linux/vfs.h>
 #include <linux/mutex.h>
 
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 517f211..80a4574 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -25,7 +25,6 @@
 #include <linux/writeback.h>
 #include <linux/blkdev.h>
 #include <linux/backing-dev.h>
-#include <linux/buffer_head.h>
 #include <linux/tracepoint.h>
 #include "internal.h"
 
diff --git a/fs/libfs.c b/fs/libfs.c
index f6d411e..5b2dbb3 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -12,7 +12,7 @@
 #include <linux/mutex.h>
 #include <linux/exportfs.h>
 #include <linux/writeback.h>
-#include <linux/buffer_head.h>
+#include <linux/buffer_head.h> /* sync_mapping_buffers */
 
 #include <asm/uaccess.h>
 
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 5b572c8..5d81e92 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -73,7 +73,6 @@
 #include <linux/security.h>
 #include <linux/kmod.h>
 #include <linux/namei.h>
-#include <linux/buffer_head.h>
 #include <linux/capability.h>
 #include <linux/quotaops.h>
 #include "../internal.h" /* ugh */
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 35f4b0e..7898cd6 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -13,7 +13,6 @@
 #include <linux/kernel.h>
 #include <linux/security.h>
 #include <linux/syscalls.h>
-#include <linux/buffer_head.h>
 #include <linux/capability.h>
 #include <linux/quotaops.h>
 #include <linux/types.h>
diff --git a/fs/splice.c b/fs/splice.c
index fa2defa..1ec0493 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -25,7 +25,6 @@
 #include <linux/mm_inline.h>
 #include <linux/swap.h>
 #include <linux/writeback.h>
-#include <linux/buffer_head.h>
 #include <linux/module.h>
 #include <linux/syscalls.h>
 #include <linux/uio.h>
diff --git a/fs/sync.c b/fs/sync.c
index 101b8ef..f3501ef 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -14,7 +14,6 @@
 #include <linux/linkage.h>
 #include <linux/pagemap.h>
 #include <linux/quotaops.h>
-#include <linux/buffer_head.h>
 #include <linux/backing-dev.h>
 #include "internal.h"
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cec429d7..e853ba5 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2092,6 +2092,7 @@ extern void bd_forget(struct inode *inode);
 extern void bdput(struct block_device *);
 extern void invalidate_bdev(struct block_device *);
 extern int sync_blockdev(struct block_device *bdev);
+extern void kill_bdev(struct block_device *);
 extern struct super_block *freeze_bdev(struct block_device *);
 extern void emergency_thaw_all(void);
 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
@@ -2099,6 +2100,7 @@ extern int fsync_bdev(struct block_device *);
 #else
 static inline void bd_forget(struct inode *inode) {}
 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
+static inline void kill_bdev(struct block_device *bdev) {}
 static inline void invalidate_bdev(struct block_device *bdev) {}
 
 static inline struct super_block *freeze_bdev(struct block_device *sb)
@@ -2415,6 +2417,7 @@ extern ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
 				unsigned long nr_segs, loff_t pos);
 extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
 			int datasync);
+extern void block_sync_page(struct page *page);
 
 /* fs/splice.c */
 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 11a594c..3739ecc 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -18,7 +18,6 @@
 #include <linux/bitops.h>
 #include <linux/genhd.h>
 #include <linux/device.h>
-#include <linux/buffer_head.h>
 #include <linux/bio.h>
 #include <linux/blkdev.h>
 #include <linux/swap.h>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 50f0824..8616ef3 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -32,7 +32,7 @@
 #include <linux/sysctl.h>
 #include <linux/cpu.h>
 #include <linux/syscalls.h>
-#include <linux/buffer_head.h>
+#include <linux/buffer_head.h> /* __set_page_dirty_buffers */
 #include <linux/pagevec.h>
 #include <trace/events/writeback.h>
 
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 78cc4d1..ea6b32d 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -13,7 +13,6 @@
 #include <linux/swapops.h>
 #include <linux/init.h>
 #include <linux/pagemap.h>
-#include <linux/buffer_head.h>
 #include <linux/backing-dev.h>
 #include <linux/pagevec.h>
 #include <linux/migrate.h>