[PATCH v1 07/14] fs: Add aop_flags parameter to create_page_buffers()

Stefan Roesch
2022-02-14T17:44:38Z

This adds the aop_flags parameter to the create_page_buffers function.
When AOP_FLAGS_NOWAIT parameter is set, the atomic allocation flag is
set. The AOP_FLAGS_NOWAIT flag is set, when async buffered writes are
enabled.

Signed-off-by: Stefan Roesch <shr@fb.com>
---
fs/buffer.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 948505480b43..5e3067173580 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1682,13 +1682,27 @@ static inline int block_size_bits(unsigned int blocksize)
return ilog2(blocksize);
}

-static struct buffer_head *create_page_buffers(struct page *page, struct inode *inode, unsigned int b_state)
+static struct buffer_head *create_page_buffers(struct page *page,
+ struct inode *inode,
+ unsigned int b_state,
+ unsigned int aop_flags)
{
BUG_ON(!PageLocked(page));

- if (!page_has_buffers(page))
- create_empty_buffers(page, 1 << READ_ONCE(inode->i_blkbits),
- b_state);
+ if (!page_has_buffers(page)) {
+ gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT;
+
+ if (aop_flags & AOP_FLAGS_NOWAIT) {
+ gfp |= GFP_ATOMIC | __GFP_NOWARN;
+ gfp &= ~__GFP_DIRECT_RECLAIM;
+ } else {
+ gfp |= __GFP_NOFAIL;
+ }
+
+ __create_empty_buffers(page, 1 << READ_ONCE(inode->i_blkbits),
+ b_state, gfp);
+ }
+
return page_buffers(page);
}

@@ -1734,7 +1748,7 @@ int __block_write_full_page(struct inode *inode, struct page *page,
int write_flags = wbc_to_write_flags(wbc);

head = create_page_buffers(page, inode,
- (1 << BH_Dirty)|(1 << BH_Uptodate));
+ (1 << BH_Dirty)|(1 << BH_Uptodate), 0);

/*
* Be very careful. We have no exclusion from __set_page_dirty_buffers
@@ -2000,7 +2014,7 @@ int __block_write_begin_int(struct folio *folio, loff_t pos, unsigned len,
BUG_ON(to > PAGE_SIZE);
BUG_ON(from > to);

- head = create_page_buffers(&folio->page, inode, 0);
+ head = create_page_buffers(&folio->page, inode, 0, flags);
blocksize = head->b_size;
bbits = block_size_bits(blocksize);

@@ -2280,7 +2294,7 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
int nr, i;
int fully_mapped = 1;

- head = create_page_buffers(page, inode, 0);
+ head = create_page_buffers(page, inode, 0, 0);
blocksize = head->b_size;
bbits = block_size_bits(blocksize);

--
2.30.2