netfs: Merge i_size update functions

Netfslib has two functions for updating the i_size after a write: one for
buffered writes into the pagecache and one for direct/unbuffered writes.
However, what needs to be done is much the same in both cases, so merge
them together.

This does raise one question, though: should updating the i_size after a
direct write do the same estimated update of i_blocks as is done for
buffered writes.

Also get rid of the cleanup function pointer from netfs_io_request as it's
only used for direct write to update i_size; instead do the i_size setting
directly from write collection.

Signed-off-by: David Howells <[e-mail]>
Link: https://lore.kernel.org/[e-mail]
cc: Steve French <[e-mail]>
cc: Paulo Alcantara <[e-mail]>
cc: [e-mail]
cc: [e-mail]
cc: [e-mail]
Signed-off-by: Christian Brauner <[e-mail]>

fs/netfs/buffered_write.c

···
  * data written into the pagecache until we can find out from the server what
  * the values actually are.
  */
-static void netfs_update_i_size(struct netfs_inode *ctx, struct inode *inode,
-				loff_t i_size, loff_t pos, size_t copied)
+void netfs_update_i_size(struct netfs_inode *ctx, struct inode *inode,
+			 loff_t pos, size_t copied)
 {
+	loff_t i_size, end = pos + copied;
 	blkcnt_t add;
 	size_t gap;
 
+	if (end <= i_size_read(inode))
+		return;
+
 	if (ctx->ops->update_i_size) {
-		ctx->ops->update_i_size(inode, pos);
+		ctx->ops->update_i_size(inode, end);
 		return;
 	}
 
 	spin_lock(&inode->i_lock);
-	i_size_write(inode, pos);
+
+	i_size = i_size_read(inode);
+	if (end > i_size) {
+		i_size_write(inode, end);
 #if IS_ENABLED(CONFIG_FSCACHE)
-	fscache_update_cookie(ctx->cache, NULL, &pos);
+		fscache_update_cookie(ctx->cache, NULL, &end);
 #endif
 
-	gap = SECTOR_SIZE - (i_size & (SECTOR_SIZE - 1));
-	if (copied > gap) {
-		add = DIV_ROUND_UP(copied - gap, SECTOR_SIZE);
+		gap = SECTOR_SIZE - (i_size & (SECTOR_SIZE - 1));
+		if (copied > gap) {
+			add = DIV_ROUND_UP(copied - gap, SECTOR_SIZE);
 
-		inode->i_blocks = min_t(blkcnt_t,
-					DIV_ROUND_UP(pos, SECTOR_SIZE),
-					inode->i_blocks + add);
+			inode->i_blocks = min_t(blkcnt_t,
+						DIV_ROUND_UP(end, SECTOR_SIZE),
+						inode->i_blocks + add);
+		}
 	}
 	spin_unlock(&inode->i_lock);
 }
···
 	struct folio *folio = NULL, *writethrough = NULL;
 	unsigned int bdp_flags = (iocb->ki_flags & IOCB_NOWAIT) ? BDP_ASYNC : 0;
 	ssize_t written = 0, ret, ret2;
-	loff_t i_size, pos = iocb->ki_pos;
+	loff_t pos = iocb->ki_pos;
 	size_t max_chunk = mapping_max_folio_size(mapping);
 	bool maybe_trouble = false;
 
···
 		flush_dcache_folio(folio);
 
 		/* Update the inode size if we moved the EOF marker */
+		netfs_update_i_size(ctx, inode, pos, copied);
 		pos += copied;
-		i_size = i_size_read(inode);
-		if (pos > i_size)
-			netfs_update_i_size(ctx, inode, i_size, pos, copied);
 		written += copied;
 
 		if (likely(!wreq)) {

fs/netfs/direct_write.c

···
 #include <linux/uio.h>
 #include "internal.h"
 
-static void netfs_cleanup_dio_write(struct netfs_io_request *wreq)
-{
-	struct inode *inode = wreq->inode;
-	unsigned long long end = wreq->start + wreq->transferred;
-
-	if (wreq->error || end <= i_size_read(inode))
-		return;
-
-	spin_lock(&inode->i_lock);
-	if (end > i_size_read(inode)) {
-		if (wreq->netfs_ops->update_i_size)
-			wreq->netfs_ops->update_i_size(inode, end);
-		else
-			i_size_write(inode, end);
-	}
-	spin_unlock(&inode->i_lock);
-}
-
 /*
  * Perform an unbuffered write where we may have to do an RMW operation on an
  * encrypted file.  This can also be used for direct I/O writes.
···
 	if (async)
 		wreq->iocb = iocb;
 	wreq->len = iov_iter_count(&wreq->buffer.iter);
-	wreq->cleanup = netfs_cleanup_dio_write;
 	ret = netfs_unbuffered_write(wreq, is_sync_kiocb(iocb), wreq->len);
 	if (ret < 0) {
 		_debug("begin = %zd", ret);

fs/netfs/internal.h

···
 			     size_t offset, size_t len);
 
 /*
+ * buffered_write.c
+ */
+void netfs_update_i_size(struct netfs_inode *ctx, struct inode *inode,
+			 loff_t pos, size_t copied);
+
+/*
  * main.c
  */
 extern unsigned int netfs_debug;

fs/netfs/write_collect.c

···
 		ictx->ops->invalidate_cache(wreq);
 	}
 
-	if (wreq->cleanup)
-		wreq->cleanup(wreq);
+	if ((wreq->origin == NETFS_UNBUFFERED_WRITE ||
+	     wreq->origin == NETFS_DIO_WRITE) &&
+	    !wreq->error)
+		netfs_update_i_size(ictx, &ictx->inode, wreq->start, wreq->transferred);
 
 	if (wreq->origin == NETFS_DIO_WRITE &&
 	    wreq->mapping->nrpages) {

include/linux/netfs.h

···
 #define NETFS_RREQ_USE_PGPRIV2		31	/* [DEPRECATED] Use PG_private_2 to mark
 						 * write to cache on read */
 	const struct netfs_request_ops *netfs_ops;
-	void (*cleanup)(struct netfs_io_request *req);
 };
 
 /*