Commit 6d840a18 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

buffer: return bool from grow_dev_folio() 

Patch series "More buffer_head cleanups", v2.

The first patch is a left-over from last cycle.  The rest fix "obvious"
block size > PAGE_SIZE problems.  I haven't tested with a large block size
setup (but I have done an ext4 xfstests run).


This patch (of 7):

Rename grow_dev_page() to grow_dev_folio() and make it return a bool. 
Document what that bool means; it's more subtle than it first appears. 
Also rename the 'failed' label to 'unlock' beacuse it's not exactly
'failed'.  It just hasn't succeeded.

Link: https://lkml.kernel.org/r/20231109210608.2252323-2-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ffda6556

fs/buffer.c

+25 −25
Original line number Diff line number Diff line
@@ -1024,40 +1024,43 @@ static sector_t folio_init_buffers(struct folio *folio, 
}



/*

 * Create the page-cache page that contains the requested block.

 * Create the page-cache folio that contains the requested block.

 *

 * This is used purely for blockdev mappings.

 *

 * Returns false if we have a 'permanent' failure.  Returns true if

 * we succeeded, or the caller should retry.

 */

static int

grow_dev_page(struct block_device *bdev, sector_t block,

	      pgoff_t index, int size, int sizebits, gfp_t gfp)

static bool grow_dev_folio(struct block_device *bdev, sector_t block,

		pgoff_t index, unsigned size, int sizebits, gfp_t gfp)

{

	struct inode *inode = bdev->bd_inode;

	struct folio *folio;

	struct buffer_head *bh;

	sector_t end_block;

	int ret = 0;

	sector_t end_block = 0;



	folio = __filemap_get_folio(inode->i_mapping, index,

			FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);

	if (IS_ERR(folio))

		return PTR_ERR(folio);

		return false;



	bh = folio_buffers(folio);

	if (bh) {

		if (bh->b_size == size) {

			end_block = folio_init_buffers(folio, bdev,

					(sector_t)index << sizebits, size);

			goto done;

			goto unlock;

		}



		/* Caller should retry if this call fails */

		end_block = ~0ULL;

		if (!try_to_free_buffers(folio))

			goto failed;

			goto unlock;

	}



	ret = -ENOMEM;

	bh = folio_alloc_buffers(folio, size, gfp | __GFP_ACCOUNT);

	if (!bh)

		goto failed;

		goto unlock;



	/*

	 * Link the folio to the buffers and initialise them.  Take the
@@ -1069,20 +1072,19 @@ grow_dev_page(struct block_device *bdev, sector_t block, 
	end_block = folio_init_buffers(folio, bdev,

			(sector_t)index << sizebits, size);

	spin_unlock(&inode->i_mapping->private_lock);

done:

	ret = (block < end_block) ? 1 : -ENXIO;

failed:

unlock:

	folio_unlock(folio);

	folio_put(folio);

	return ret;

	return block < end_block;

}



/*

 * Create buffers for the specified block device block's page.  If

 * that page was dirty, the buffers are set dirty also.

 * Create buffers for the specified block device block's folio.  If

 * that folio was dirty, the buffers are set dirty also.  Returns false

 * if we've hit a permanent error.

 */

static int

grow_buffers(struct block_device *bdev, sector_t block, int size, gfp_t gfp)

static bool grow_buffers(struct block_device *bdev, sector_t block,

		unsigned size, gfp_t gfp)

{

	pgoff_t index;

	int sizebits;
@@ -1099,11 +1101,11 @@ grow_buffers(struct block_device *bdev, sector_t block, int size, gfp_t gfp) 
			"device %pg\n",

			__func__, (unsigned long long)block,

			bdev);

		return -EIO;

		return false;

	}



	/* Create a page with the proper size buffers.. */

	return grow_dev_page(bdev, block, index, size, sizebits, gfp);

	/* Create a folio with the proper size buffers */

	return grow_dev_folio(bdev, block, index, size, sizebits, gfp);

}



static struct buffer_head *
@@ -1124,14 +1126,12 @@ __getblk_slow(struct block_device *bdev, sector_t block, 


	for (;;) {

		struct buffer_head *bh;

		int ret;



		bh = __find_get_block(bdev, block, size);

		if (bh)

			return bh;



		ret = grow_buffers(bdev, block, size, gfp);

		if (ret < 0)

		if (!grow_buffers(bdev, block, size, gfp))

			return NULL;

	}

}