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>

10 files changed, 28 insertions, 61 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 7866cdd9fe70..69a5b6fbee2b 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 19d8eb7fdc81..1a30db77af32 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 1064805e653b..67bef6d01484 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 739fb59bcdc2..c37adb222113 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 517f211a3bd4..80a4574028f1 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 f6d411eef1e7..5b2dbb3ba4fc 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 5b572c89e6c4..5d81e92daf83 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 35f4b0ecdeb3..7898cd688a00 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 fa2defa8afcf..1ec0493266b3 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 101b8ef901d7..f3501ef39235 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"