Commit a40759fb authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Theodore Ts'o
Browse files

ext4: remove array of buffer_heads from mext_page_mkuptodate() 



Iterate the folio's list of buffer_heads twice instead of keeping
an array of pointers.  This solves a too-large-array-for-stack problem
on architectures with a ridiculoously large PAGE_SIZE and prepares
ext4 to support larger folios.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20240718223005.568869-3-willy@infradead.org


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 368a83ce

fs/ext4/move_extent.c

+12 −10
Original line number Diff line number Diff line
@@ -166,15 +166,14 @@ mext_folio_double_lock(struct inode *inode1, struct inode *inode2, 
	return 0;

}



/* Force page buffers uptodate w/o dropping page's lock */

static int

mext_page_mkuptodate(struct folio *folio, unsigned from, unsigned to)

/* Force folio buffers uptodate w/o dropping folio's lock */

static int mext_page_mkuptodate(struct folio *folio, size_t from, size_t to)

{

	struct inode *inode = folio->mapping->host;

	sector_t block;

	struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];

	struct buffer_head *bh, *head;

	unsigned int blocksize, block_start, block_end;

	int i, nr = 0;

	int nr = 0;

	bool partial = false;



	BUG_ON(!folio_test_locked(folio));
@@ -215,20 +214,23 @@ mext_page_mkuptodate(struct folio *folio, unsigned from, unsigned to) 
			continue;

		}

		ext4_read_bh_nowait(bh, 0, NULL);

		BUG_ON(nr >= MAX_BUF_PER_PAGE);

		arr[nr++] = bh;

		nr++;

	}

	/* No io required */

	if (!nr)

		goto out;



	for (i = 0; i < nr; i++) {

		bh = arr[i];

	bh = head;

	do {

		if (bh_offset(bh) + blocksize <= from)

			continue;

		if (bh_offset(bh) > to)

			break;

		wait_on_buffer(bh);

		if (buffer_uptodate(bh))

			continue;

		return -EIO;

	}

	} while ((bh = bh->b_this_page) != head);

out:

	if (!partial)

		folio_mark_uptodate(folio);