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: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20240718223005.568869-3-willy@infradead.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Matthew Wilcox (Oracle) 2024-07-18 23:30:01 +01:00 committed by Theodore Ts'o
parent 368a83cebb
commit a40759fb16

View file

@ -166,15 +166,14 @@ mext_folio_double_lock(struct inode *inode1, struct inode *inode2,
return 0; return 0;
} }
/* Force page buffers uptodate w/o dropping page's lock */ /* Force folio buffers uptodate w/o dropping folio's lock */
static int static int mext_page_mkuptodate(struct folio *folio, size_t from, size_t to)
mext_page_mkuptodate(struct folio *folio, unsigned from, unsigned to)
{ {
struct inode *inode = folio->mapping->host; struct inode *inode = folio->mapping->host;
sector_t block; 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; unsigned int blocksize, block_start, block_end;
int i, nr = 0; int nr = 0;
bool partial = false; bool partial = false;
BUG_ON(!folio_test_locked(folio)); BUG_ON(!folio_test_locked(folio));
@ -215,20 +214,23 @@ mext_page_mkuptodate(struct folio *folio, unsigned from, unsigned to)
continue; continue;
} }
ext4_read_bh_nowait(bh, 0, NULL); ext4_read_bh_nowait(bh, 0, NULL);
BUG_ON(nr >= MAX_BUF_PER_PAGE); nr++;
arr[nr++] = bh;
} }
/* No io required */ /* No io required */
if (!nr) if (!nr)
goto out; goto out;
for (i = 0; i < nr; i++) { bh = head;
bh = arr[i]; do {
if (bh_offset(bh) + blocksize <= from)
continue;
if (bh_offset(bh) > to)
break;
wait_on_buffer(bh); wait_on_buffer(bh);
if (buffer_uptodate(bh)) if (buffer_uptodate(bh))
continue; continue;
return -EIO; return -EIO;
} } while ((bh = bh->b_this_page) != head);
out: out:
if (!partial) if (!partial)
folio_mark_uptodate(folio); folio_mark_uptodate(folio);