[PATCH v13 101/137] iomap: Convert iomap_write_begin and iomap_write_end to folios

Matthew Wilcox (Oracle)
2021-07-12T04:01:58Z

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

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
fs/iomap/buffered-io.c | 68 ++++++++++++++++++++++--------------------
1 file changed, 36 insertions(+), 32 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 2ecfebdd1f4f..1df401c6e55a 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -541,9 +541,8 @@ static int iomap_read_folio_sync(loff_t block_start, struct folio *folio,

static int
__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
- struct page *page, struct iomap *srcmap)
+ struct folio *folio, struct iomap *srcmap)
{
- struct folio *folio = page_folio(page);
struct iomap_page *iop = iomap_page_create(inode, folio);
loff_t block_size = i_blocksize(inode);
loff_t block_start = round_down(pos, block_size);
@@ -583,12 +582,14 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
return 0;
}

-static int
-iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
- struct page **pagep, struct iomap *iomap, struct iomap *srcmap)
+static int iomap_write_begin(struct inode *inode, loff_t pos, size_t len,
+ unsigned flags, struct folio **foliop, struct iomap *iomap,
+ struct iomap *srcmap)
{
const struct iomap_page_ops *page_ops = iomap->page_ops;
+ 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 > iomap->offset + iomap->length);
@@ -604,30 +605,31 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
return status;
}

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

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

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(inode, pos, len);

out_no_page:
@@ -637,11 +639,10 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
}

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
@@ -654,10 +655,10 @@ static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
* 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_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;
}

@@ -680,9 +681,10 @@ static size_t iomap_write_end_inline(struct inode *inode, struct page *page,

/* Returns the number of bytes copied. May be 0. Cannot be an errno. */
static size_t iomap_write_end(struct inode *inode, loff_t pos, size_t len,
- size_t copied, struct page *page, struct iomap *iomap,
+ size_t copied, struct folio *folio, struct iomap *iomap,
struct iomap *srcmap)
{
+ struct page *page = folio_file_page(folio, pos / PAGE_SIZE);
const struct iomap_page_ops *page_ops = iomap->page_ops;
loff_t old_size = inode->i_size;
size_t ret;
@@ -693,7 +695,7 @@ static size_t iomap_write_end(struct inode *inode, loff_t pos, size_t len,
ret = block_write_end(NULL, inode->i_mapping, pos, len, copied,
page, NULL);
} else {
- ret = __iomap_write_end(inode, pos, len, copied, page);
+ ret = __iomap_write_end(inode, pos, len, copied, folio);
}

/*
@@ -705,13 +707,13 @@ static size_t iomap_write_end(struct inode *inode, loff_t pos, size_t len,
i_size_write(inode, pos + ret);
iomap->flags |= IOMAP_F_SIZE_CHANGED;
}
- unlock_page(page);
+ folio_unlock(folio);

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

if (ret < len)
iomap_write_failed(inode, pos, len);
@@ -727,6 +729,7 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
ssize_t written = 0;

do {
+ struct folio *folio;
struct page *page;
unsigned long offset; /* Offset into pagecache page */
unsigned long bytes; /* Bytes to write to page */
@@ -750,18 +753,19 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
break;
}

- status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap,
+ status = iomap_write_begin(inode, pos, bytes, 0, &folio, iomap,
srcmap);
if (unlikely(status))
break;

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

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

- status = iomap_write_end(inode, pos, bytes, copied, page, iomap,
- srcmap);
+ status = iomap_write_end(inode, pos, bytes, copied, folio,
+ iomap, srcmap);

if (unlikely(copied != status))
iov_iter_revert(i, copied - status);
@@ -825,14 +829,14 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
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(inode, pos, bytes,
- IOMAP_WRITE_F_UNSHARE, &page, iomap, srcmap);
+ IOMAP_WRITE_F_UNSHARE, &folio, iomap, srcmap);
if (unlikely(status))
return status;

- status = iomap_write_end(inode, pos, bytes, bytes, page, iomap,
+ status = iomap_write_end(inode, pos, bytes, bytes, folio, iomap,
srcmap);
if (WARN_ON_ONCE(status == 0))
return -EIO;
@@ -871,19 +875,19 @@ EXPORT_SYMBOL_GPL(iomap_file_unshare);
static s64 iomap_zero(struct inode *inode, loff_t pos, u64 length,
struct iomap *iomap, struct iomap *srcmap)
{
- 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(inode, pos, bytes, 0, &page, iomap, srcmap);
+ status = iomap_write_begin(inode, pos, bytes, 0, &folio, iomap, srcmap);
if (status)
return status;

- zero_user(page, offset, bytes);
- mark_page_accessed(page);
+ zero_user(folio_file_page(folio, pos / PAGE_SIZE), offset, bytes);
+ folio_mark_accessed(folio);

- return iomap_write_end(inode, pos, bytes, bytes, page, iomap, srcmap);
+ return iomap_write_end(inode, pos, bytes, bytes, folio, iomap, srcmap);
}

static loff_t iomap_zero_range_actor(struct inode *inode, loff_t pos,
--
2.30.2