6.6-stable review patch. If anyone has any objections, please let me know.
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From: Matthew Wilcox (Oracle) willy@infradead.org
[ Upstream commit a40759fb16ae839f8c769174fde017564ea564ff ]
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 Stable-dep-of: 2f3d93e210b9 ("ext4: fix race in buffer_head read fault injection") Signed-off-by: Sasha Levin sashal@kernel.org --- 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 28d59548770d7..f082bccdb01ad 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -165,15 +165,14 @@ 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)); @@ -216,20 +215,23 @@ 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);