Move the page_done callback into a separate iomap_page_ops structure and
add a page_prepare calback to be called before a page is written to. In
gfs2, we'll want to start a transaction in page_prepare and end it in
page_done, and other filesystems that implement data journaling will
require the same kind of mechanism.
Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
fs/iomap.c | 22 ++++++++++++++++++----
include/linux/iomap.h | 18 +++++++++++++-----
2 files changed, 31 insertions(+), 9 deletions(-)
diff --git a/fs/iomap.c b/fs/iomap.c
index 97cb9d486a7d..667a822ecb7d 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -665,6 +665,7 @@ static int
iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
struct page **pagep, struct iomap *iomap)
{
+ const struct iomap_page_ops *page_ops = iomap->page_ops;
pgoff_t index = pos >> PAGE_SHIFT;
struct page *page;
int status = 0;
@@ -674,9 +675,17 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
if (fatal_signal_pending(current))
return -EINTR;
+ if (page_ops) {
+ status = page_ops->page_prepare(inode, pos, len, iomap);
+ if (status)
+ return status;
+ }
+
page = grab_cache_page_write_begin(inode->i_mapping, index, flags);
- if (!page)
- return -ENOMEM;
+ if (!page) {
+ status = -ENOMEM;
+ goto no_page;
+ }
if (iomap->type == IOMAP_INLINE)
iomap_read_inline_data(inode, page, iomap);
@@ -684,12 +693,16 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
status = __block_write_begin_int(page, pos, len, NULL, iomap);
else
status = __iomap_write_begin(inode, pos, len, page, iomap);
+
if (unlikely(status)) {
unlock_page(page);
put_page(page);
page = NULL;
iomap_write_failed(inode, pos, len);
+no_page:
+ if (page_ops)
+ page_ops->page_done(inode, pos, 0, NULL, iomap);
}
*pagep = page;
@@ -769,6 +782,7 @@ static int
iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
unsigned copied, struct page *page, struct iomap *iomap)
{
+ const struct iomap_page_ops *page_ops = iomap->page_ops;
int ret;
if (iomap->type == IOMAP_INLINE) {
@@ -780,8 +794,8 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
ret = __iomap_write_end(inode, pos, len, copied, page, iomap);
}
- if (iomap->page_done)
- iomap->page_done(inode, pos, copied, page, iomap);
+ if (page_ops)
+ page_ops->page_done(inode, pos, copied, page, iomap);
if (ret < len)
iomap_write_failed(inode, pos, len);
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 0fefb5455bda..fd65f27d300e 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -53,6 +53,8 @@ struct vm_fault;
*/
#define IOMAP_NULL_ADDR -1ULL /* addr is not valid */
+struct iomap_page_ops;
+
struct iomap {
u64 addr; /* disk offset of mapping, bytes */
loff_t offset; /* file offset of mapping, bytes */
@@ -63,12 +65,18 @@ struct iomap {
struct dax_device *dax_dev; /* dax_dev for dax operations */
void *inline_data;
void *private; /* filesystem private */
+ const struct iomap_page_ops *page_ops;
+};
- /*
- * Called when finished processing a page in the mapping returned in
- * this iomap. At least for now this is only supported in the buffered
- * write path.
- */
+/*
+ * Called before / after processing a page in the mapping returned in this
+ * iomap. At least for now, this is only supported in the buffered write path.
+ * When page_prepare returns 0, page_done is called as well
+ * (possibly with page == NULL).
+ */
+struct iomap_page_ops {
+ int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,
+ struct iomap *iomap);
void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
struct page *page, struct iomap *iomap);
};
--
2.20.1
