[PATCH 15/21] iomap: Convert iomap_write_begin and iomap_write_end to folios

Matthew Wilcox (Oracle)
2021-11-01T21:08:09Z

These functions still only work in PAGE_SIZE chunks, but there are
fewer conversions from tail to head pages as a result of this patch.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
fs/iomap/buffered-io.c | 67 ++++++++++++++++++++++--------------------
1 file changed, 35 insertions(+), 32 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index b55d947867b1..6df8fdbb1951 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -539,9 +539,8 @@ static int iomap_read_folio_sync(loff_t block_start, struct folio *folio,
}

static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
- unsigned len, struct page *page)
+ size_t len, struct folio *folio)
{
- struct folio *folio = page_folio(page);
const struct iomap *srcmap = iomap_iter_srcmap(iter);
struct iomap_page *iop = iomap_page_create(iter->inode, folio);
loff_t block_size = i_blocksize(iter->inode);
@@ -583,9 +582,8 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
}

static int iomap_write_begin_inline(const struct iomap_iter *iter,
- struct page *page)
+ struct folio *folio)
{
- struct folio *folio = page_folio(page);
int ret;

/* needs more work for the tailpacking case; disable for now */
@@ -598,11 +596,13 @@ static int iomap_write_begin_inline(const struct iomap_iter *iter,
}

static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
- unsigned len, struct page **pagep)
+ size_t len, struct folio **foliop)
{
const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
+ struct folio *folio;
struct page *page;
+ unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS;
int status = 0;

BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length);
@@ -618,29 +618,30 @@ static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
return status;
}

- page = grab_cache_page_write_begin(iter->inode->i_mapping,
- pos >> PAGE_SHIFT, AOP_FLAG_NOFS);
- if (!page) {
+ folio = __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,
+ fgp, mapping_gfp_mask(iter->inode->i_mapping));
+ if (!folio) {
status = -ENOMEM;
goto out_no_page;
}

+ page = folio_file_page(folio, pos >> PAGE_SHIFT);
if (srcmap->type == IOMAP_INLINE)
- status = iomap_write_begin_inline(iter, page);
+ status = iomap_write_begin_inline(iter, folio);
else if (srcmap->flags & IOMAP_F_BUFFER_HEAD)
status = __block_write_begin_int(page, pos, len, NULL, srcmap);
else
- status = __iomap_write_begin(iter, pos, len, page);
+ status = __iomap_write_begin(iter, pos, len, folio);

if (unlikely(status))
goto out_unlock;

- *pagep = page;
+ *foliop = folio;
return 0;

out_unlock:
- unlock_page(page);
- put_page(page);
+ folio_unlock(folio);
+ folio_put(folio);
iomap_write_failed(iter->inode, pos, len);

out_no_page:
@@ -650,11 +651,10 @@ static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
}

static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
- size_t copied, struct page *page)
+ size_t copied, struct folio *folio)
{
- struct folio *folio = page_folio(page);
struct iomap_page *iop = to_iomap_page(folio);
- flush_dcache_page(page);
+ flush_dcache_folio(folio);

/*
* The blocks that were entirely written will now be uptodate, so we
@@ -667,10 +667,10 @@ static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
* non-uptodate page as a zero-length write, and force the caller to
* redo the whole thing.
*/
- if (unlikely(copied < len && !PageUptodate(page)))
+ if (unlikely(copied < len && !folio_test_uptodate(folio)))
return 0;
iomap_set_range_uptodate(folio, iop, offset_in_folio(folio, pos), len);
- __set_page_dirty_nobuffers(page);
+ filemap_dirty_folio(inode->i_mapping, folio);
return copied;
}

@@ -694,8 +694,9 @@ static size_t iomap_write_end_inline(const struct iomap_iter *iter,

/* Returns the number of bytes copied. May be 0. Cannot be an errno. */
static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
- size_t copied, struct page *page)
+ size_t copied, struct folio *folio)
{
+ struct page *page = folio_file_page(folio, pos >> PAGE_SHIFT);
const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
loff_t old_size = iter->inode->i_size;
@@ -707,7 +708,7 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
ret = block_write_end(NULL, iter->inode->i_mapping, pos, len,
copied, page, NULL);
} else {
- ret = __iomap_write_end(iter->inode, pos, len, copied, page);
+ ret = __iomap_write_end(iter->inode, pos, len, copied, folio);
}

/*
@@ -719,13 +720,13 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
i_size_write(iter->inode, pos + ret);
iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
}
- unlock_page(page);
+ folio_unlock(folio);

if (old_size < pos)
pagecache_isize_extended(iter->inode, old_size, pos);
if (page_ops && page_ops->page_done)
page_ops->page_done(iter->inode, pos, ret, page);
- put_page(page);
+ folio_put(folio);

if (ret < len)
iomap_write_failed(iter->inode, pos, len);
@@ -740,6 +741,7 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
long status = 0;

do {
+ struct folio *folio;
struct page *page;
unsigned long offset; /* Offset into pagecache page */
unsigned long bytes; /* Bytes to write to page */
@@ -763,16 +765,17 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
break;
}

- status = iomap_write_begin(iter, pos, bytes, &page);
+ status = iomap_write_begin(iter, pos, bytes, &folio);
if (unlikely(status))
break;

+ page = folio_file_page(folio, pos >> PAGE_SHIFT);
if (mapping_writably_mapped(iter->inode->i_mapping))
flush_dcache_page(page);

copied = copy_page_from_iter_atomic(page, offset, bytes, i);

- status = iomap_write_end(iter, pos, bytes, copied, page);
+ status = iomap_write_end(iter, pos, bytes, copied, folio);

if (unlikely(copied != status))
iov_iter_revert(i, copied - status);
@@ -838,13 +841,13 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
do {
unsigned long offset = offset_in_page(pos);
unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length);
- struct page *page;
+ struct folio *folio;

- status = iomap_write_begin(iter, pos, bytes, &page);
+ status = iomap_write_begin(iter, pos, bytes, &folio);
if (unlikely(status))
return status;

- status = iomap_write_end(iter, pos, bytes, bytes, page);
+ status = iomap_write_end(iter, pos, bytes, bytes, folio);
if (WARN_ON_ONCE(status == 0))
return -EIO;

@@ -880,19 +883,19 @@ EXPORT_SYMBOL_GPL(iomap_file_unshare);

static s64 __iomap_zero_iter(struct iomap_iter *iter, loff_t pos, u64 length)
{
- struct page *page;
+ struct folio *folio;
int status;
unsigned offset = offset_in_page(pos);
unsigned bytes = min_t(u64, PAGE_SIZE - offset, length);

- status = iomap_write_begin(iter, pos, bytes, &page);
+ status = iomap_write_begin(iter, pos, bytes, &folio);
if (status)
return status;

- zero_user(page, offset, bytes);
- mark_page_accessed(page);
+ zero_user(folio_file_page(folio, pos >> PAGE_SHIFT), offset, bytes);
+ folio_mark_accessed(folio);

- return iomap_write_end(iter, pos, bytes, bytes, page);
+ return iomap_write_end(iter, pos, bytes, bytes, folio);
}

static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
--
2.33.0