1 files changed, 102 insertions, 13 deletions

diff --git a/fs/iomap.c b/fs/iomap.c
index 48141b8eff5f..013d1d36fbbf 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -27,9 +27,6 @@
 #include <linux/dax.h>
 #include "internal.h"
 
-typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
-		void *data, struct iomap *iomap);
-
 /*
  * Execute a iomap write on a segment of the mapping that spans a
  * contiguous range of pages that have identical block mapping state.
@@ -41,7 +38,7 @@ typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
  * resources they require in the iomap_begin call, and release them in the
  * iomap_end call.
  */
-static loff_t
+loff_t
 iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
 		struct iomap_ops *ops, void *data, iomap_actor_t actor)
 {
@@ -84,8 +81,11 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
 	 * Now the data has been copied, commit the range we've copied.  This
 	 * should not fail unless the filesystem has had a fatal error.
 	 */
-	ret = ops->iomap_end(inode, pos, length, written > 0 ? written : 0,
-			flags, &iomap);
+	if (ops->iomap_end) {
+		ret = ops->iomap_end(inode, pos, length,
+				     written > 0 ? written : 0,
+				     flags, &iomap);
+	}
 
 	return written ? written : ret;
 }
@@ -194,12 +194,9 @@ again:
 		if (mapping_writably_mapped(inode->i_mapping))
 			flush_dcache_page(page);
 
-		pagefault_disable();
 		copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
-		pagefault_enable();
 
 		flush_dcache_page(page);
-		mark_page_accessed(page);
 
 		status = iomap_write_end(inode, pos, bytes, copied, page);
 		if (unlikely(status < 0))
@@ -252,6 +249,88 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter,
 }
 EXPORT_SYMBOL_GPL(iomap_file_buffered_write);
 
+static struct page *
+__iomap_read_page(struct inode *inode, loff_t offset)
+{
+	struct address_space *mapping = inode->i_mapping;
+	struct page *page;
+
+	page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL);
+	if (IS_ERR(page))
+		return page;
+	if (!PageUptodate(page)) {
+		put_page(page);
+		return ERR_PTR(-EIO);
+	}
+	return page;
+}
+
+static loff_t
+iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
+		struct iomap *iomap)
+{
+	long status = 0;
+	ssize_t written = 0;
+
+	do {
+		struct page *page, *rpage;
+		unsigned long offset;	/* Offset into pagecache page */
+		unsigned long bytes;	/* Bytes to write to page */
+
+		offset = (pos & (PAGE_SIZE - 1));
+		bytes = min_t(unsigned long, PAGE_SIZE - offset, length);
+
+		rpage = __iomap_read_page(inode, pos);
+		if (IS_ERR(rpage))
+			return PTR_ERR(rpage);
+
+		status = iomap_write_begin(inode, pos, bytes,
+				AOP_FLAG_NOFS | AOP_FLAG_UNINTERRUPTIBLE,
+				&page, iomap);
+		put_page(rpage);
+		if (unlikely(status))
+			return status;
+
+		WARN_ON_ONCE(!PageUptodate(page));
+
+		status = iomap_write_end(inode, pos, bytes, bytes, page);
+		if (unlikely(status <= 0)) {
+			if (WARN_ON_ONCE(status == 0))
+				return -EIO;
+			return status;
+		}
+
+		cond_resched();
+
+		pos += status;
+		written += status;
+		length -= status;
+
+		balance_dirty_pages_ratelimited(inode->i_mapping);
+	} while (length);
+
+	return written;
+}
+
+int
+iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
+		struct iomap_ops *ops)
+{
+	loff_t ret;
+
+	while (len) {
+		ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL,
+				iomap_dirty_actor);
+		if (ret <= 0)
+			return ret;
+		pos += ret;
+		len -= ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iomap_file_dirty);
+
 static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
 		unsigned bytes, struct iomap *iomap)
 {
@@ -428,9 +507,14 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi,
 		break;
 	}
 
+	if (iomap->flags & IOMAP_F_MERGED)
+		flags |= FIEMAP_EXTENT_MERGED;
+	if (iomap->flags & IOMAP_F_SHARED)
+		flags |= FIEMAP_EXTENT_SHARED;
+
 	return fiemap_fill_next_extent(fi, iomap->offset,
 			iomap->blkno != IOMAP_NULL_BLOCK ? iomap->blkno << 9: 0,
-			iomap->length, flags | FIEMAP_EXTENT_MERGED);
+			iomap->length, flags);
 
 }
 
@@ -470,13 +554,18 @@ int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,
 	if (ret)
 		return ret;
 
-	ret = filemap_write_and_wait(inode->i_mapping);
-	if (ret)
-		return ret;
+	if (fi->fi_flags & FIEMAP_FLAG_SYNC) {
+		ret = filemap_write_and_wait(inode->i_mapping);
+		if (ret)
+			return ret;
+	}
 
 	while (len > 0) {
 		ret = iomap_apply(inode, start, len, 0, ops, &ctx,
 				iomap_fiemap_actor);
+		/* inode with no (attribute) mapping will give ENOENT */
+		if (ret == -ENOENT)
+			break;
 		if (ret < 0)
 			return ret;
 		if (ret == 0)