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: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
fs/ext4/move_extent.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 6d651ad788ac..660bf34a5c4b 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -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);
--
2.43.0
