[patch 1/12] misc fixes

[Andrew Morton <akpm@zip.com.au>]

- Remove the IO error warning in end_buffer_io_sync().  Failed READA
  attempts trigger it.

- Emit a warning when an ext2 is mounting an ext3 filesystem.

  We have had quite a few problem reports related to this, mainly
  arising from initrd problems.  And mount(8) tends to report the
  fstype from /etc/fstab rather than reporting what has really
  happened.

Fixes some bogosity which I added to max_block():

- `size' doesn't need to be sector_t

- `retval' should not be initialised to "~0UL" because that is
  0x00000000ffffffff with 64-bit sector_t.

- /proc/partitions shows wrong number of blocks (Badari Pulavarty)

- Allocate task_structs with GFP_KERNEL, as discussed.

- Convert the EXPORT_SYMBOL for generic_file_direct_IO() to
  EXPORT_SYMBOL_GPL.  That was only exported as a practicality for the
  raw driver.

- Make the loop thread run balance_dirty_pages() after dirtying the
  backing file.  So it will perform writeback of the backing file when
  dirty memory levels are high.  Export balance_dirty_pages to GPL
  modules for this.

  This makes loop work a lot better - I suspect it broke when callers
  of balance_dirty_pages() started writing back only their own queue.

  There are many page allocation failures under heavy loop writeout. 
  Coming from blk_queue_bounce()'s allocation from the page_pool
  mempool.  So...

- Disable page allocation warnings around the initial atomic
  allocation attempt in mempool_alloc() - the one where __GFP_WAIT and
  __GFP_IO were turned off.  That one can easily fail.

- Add some commentary in block_write_full_page()


 drivers/block/genhd.c |    2 +-
 drivers/block/loop.c  |    2 ++
 fs/block_dev.c        |    6 +++---
 fs/buffer.c           |   13 +++++++++++--
 fs/ext2/super.c       |    3 +++
 kernel/fork.c         |    5 +++--
 kernel/ksyms.c        |    2 +-
 mm/mempool.c          |    2 ++
 mm/page-writeback.c   |    1 +
 9 files changed, 27 insertions, 9 deletions

--- 2.5.30/fs/buffer.c~misc	Fri Aug  9 17:36:38 2002
+++ 2.5.30-akpm/fs/buffer.c	Fri Aug  9 17:37:02 2002
@@ -180,7 +180,10 @@ void end_buffer_io_sync(struct buffer_he
 	if (uptodate) {
 		set_buffer_uptodate(bh);
 	} else {
-		buffer_io_error(bh);
+		/*
+		 * This happens, due to failed READA attempts.
+		 * buffer_io_error(bh);
+		 */
 		clear_buffer_uptodate(bh);
 	}
 	unlock_buffer(bh);
@@ -2283,7 +2286,13 @@ int block_write_full_page(struct page *p
 		return -EIO;
 	}
 
-	/* The page straddles i_size */
+	/*
+	 * The page straddles i_size.  It must be zeroed out on each and every
+	 * writepage invokation because it may be mmapped.  "A file is mapped
+	 * in multiples of the page size.  For a file that is not a multiple of
+	 * the  page size, the remaining memory is zeroed when mapped, and
+	 * writes to that region are not written out to the file."
+	 */
 	kaddr = kmap(page);
 	memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
 	flush_dcache_page(page);
--- 2.5.30/fs/block_dev.c~misc	Fri Aug  9 17:36:38 2002
+++ 2.5.30-akpm/fs/block_dev.c	Fri Aug  9 17:37:00 2002
@@ -26,12 +26,12 @@
 
 static sector_t max_block(struct block_device *bdev)
 {
-	sector_t retval = ~0U;
+	sector_t retval = ~0;
 	loff_t sz = bdev->bd_inode->i_size;
 
 	if (sz) {
-		sector_t size = block_size(bdev);
-		unsigned sizebits = blksize_bits(size);
+		unsigned int size = block_size(bdev);
+		unsigned int sizebits = blksize_bits(size);
 		retval = (sz >> sizebits);
 	}
 	return retval;
--- 2.5.30/fs/ext2/super.c~misc	Fri Aug  9 17:36:38 2002
+++ 2.5.30-akpm/fs/ext2/super.c	Fri Aug  9 17:36:38 2002
@@ -698,6 +698,9 @@ static int ext2_fill_super(struct super_
 			printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 		goto failed_mount2;
 	}
+	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
+		ext2_warning(sb, __FUNCTION__,
+			"mounting ext3 filesystem as ext2\n");
 	ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 	return 0;
 failed_mount2:
--- 2.5.30/drivers/block/genhd.c~misc	Fri Aug  9 17:36:38 2002
+++ 2.5.30-akpm/drivers/block/genhd.c	Fri Aug  9 17:36:38 2002
@@ -166,7 +166,7 @@ static int show_partition(struct seq_fil
 			continue;
 		seq_printf(part, "%4d  %4d %10ld %s\n",
 			sgp->major, n + sgp->first_minor,
-			sgp->part[n].nr_sects << 1,
+			sgp->part[n].nr_sects >> 1,
 			disk_name(sgp, n + sgp->first_minor, buf));
 	}
 
--- 2.5.30/kernel/fork.c~misc	Fri Aug  9 17:36:38 2002
+++ 2.5.30-akpm/kernel/fork.c	Fri Aug  9 17:36:38 2002
@@ -106,9 +106,10 @@ static struct task_struct *dup_task_stru
 	struct thread_info *ti;
 
 	ti = alloc_thread_info();
-	if (!ti) return NULL;
+	if (!ti)
+		return NULL;
 
-	tsk = kmem_cache_alloc(task_struct_cachep,GFP_ATOMIC);
+	tsk = kmem_cache_alloc(task_struct_cachep, GFP_KERNEL);
 	if (!tsk) {
 		free_thread_info(ti);
 		return NULL;
--- 2.5.30/kernel/ksyms.c~misc	Fri Aug  9 17:36:38 2002
+++ 2.5.30-akpm/kernel/ksyms.c	Fri Aug  9 17:36:38 2002
@@ -342,7 +342,7 @@ EXPORT_SYMBOL(register_disk);
 EXPORT_SYMBOL(read_dev_sector);
 EXPORT_SYMBOL(init_buffer);
 EXPORT_SYMBOL(wipe_partitions);
-EXPORT_SYMBOL(generic_file_direct_IO);
+EXPORT_SYMBOL_GPL(generic_file_direct_IO);
 
 /* tty routines */
 EXPORT_SYMBOL(tty_hangup);
--- 2.5.30/drivers/block/loop.c~misc	Fri Aug  9 17:36:38 2002
+++ 2.5.30-akpm/drivers/block/loop.c	Fri Aug  9 17:37:02 2002
@@ -74,6 +74,7 @@
 #include <linux/slab.h>
 #include <linux/loop.h>
 #include <linux/suspend.h>
+#include <linux/writeback.h>
 #include <linux/buffer_head.h>		/* for invalidate_bdev() */
 
 #include <asm/uaccess.h>
@@ -235,6 +236,7 @@ do_lo_send(struct loop_device *lo, struc
 	up(&mapping->host->i_sem);
 out:
 	kunmap(bvec->bv_page);
+	balance_dirty_pages(mapping);
 	return ret;
 
 unlock:
--- 2.5.30/mm/page-writeback.c~misc	Fri Aug  9 17:36:38 2002
+++ 2.5.30-akpm/mm/page-writeback.c	Fri Aug  9 17:37:00 2002
@@ -133,6 +133,7 @@ void balance_dirty_pages(struct address_
 	if (!writeback_in_progress(bdi) && ps.nr_dirty > background_thresh)
 		pdflush_operation(background_writeout, 0);
 }
+EXPORT_SYMBOL_GPL(balance_dirty_pages);
 
 /**
  * balance_dirty_pages_ratelimited - balance dirty memory state
--- 2.5.30/mm/mempool.c~misc	Fri Aug  9 17:36:38 2002
+++ 2.5.30-akpm/mm/mempool.c	Fri Aug  9 17:36:38 2002
@@ -189,7 +189,9 @@ void * mempool_alloc(mempool_t *pool, in
 	int gfp_nowait = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
 
 repeat_alloc:
+	current->flags |= PF_NOWARN;
 	element = pool->alloc(gfp_nowait, pool->pool_data);
+	current->flags &= ~PF_NOWARN;
 	if (likely(element != NULL))
 		return element;
 

.