Commit 3c435a0f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Andrew Morton
Browse files

filemap: add a kiocb_write_and_wait helper 

Factor out a helper that does filemap_write_and_wait_range for the range
covered by a read kiocb, or returns -EAGAIN if the kiocb is marked as
nowait and there would be pages to write.

Link: https://lkml.kernel.org/r/20230601145904.1385409-5-hch@lst.de


Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Acked-by: default avatarDarrick J. Wong <djwong@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Chao Yu <chao@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 182c25e9

block/fops.c

+3 −15
Original line number Diff line number Diff line
@@ -576,21 +576,9 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 
		goto reexpand; /* skip atime */



	if (iocb->ki_flags & IOCB_DIRECT) {

		struct address_space *mapping = iocb->ki_filp->f_mapping;



		if (iocb->ki_flags & IOCB_NOWAIT) {

			if (filemap_range_needs_writeback(mapping, pos,

							  pos + count - 1)) {

				ret = -EAGAIN;

				goto reexpand;

			}

		} else {

			ret = filemap_write_and_wait_range(mapping, pos,

							   pos + count - 1);

		ret = kiocb_write_and_wait(iocb, count);

		if (ret < 0)

			goto reexpand;

		}



		file_accessed(iocb->ki_filp);



		ret = blkdev_direct_IO(iocb, to);

include/linux/pagemap.h

+2 −0
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ static inline void invalidate_remote_inode(struct inode *inode) 
int invalidate_inode_pages2(struct address_space *mapping);

int invalidate_inode_pages2_range(struct address_space *mapping,

		pgoff_t start, pgoff_t end);



int write_inode_now(struct inode *, int sync);

int filemap_fdatawrite(struct address_space *);

int filemap_flush(struct address_space *);
@@ -54,6 +55,7 @@ int filemap_check_errors(struct address_space *mapping); 
void __filemap_set_wb_err(struct address_space *mapping, int err);

int filemap_fdatawrite_wbc(struct address_space *mapping,

			   struct writeback_control *wbc);

int kiocb_write_and_wait(struct kiocb *iocb, size_t count);



static inline int filemap_write_and_wait(struct address_space *mapping)

{

mm/filemap.c

+18 −12
Original line number Diff line number Diff line
@@ -2735,6 +2735,21 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter, 
}

EXPORT_SYMBOL_GPL(filemap_read);



int kiocb_write_and_wait(struct kiocb *iocb, size_t count)

{

	struct address_space *mapping = iocb->ki_filp->f_mapping;

	loff_t pos = iocb->ki_pos;

	loff_t end = pos + count - 1;



	if (iocb->ki_flags & IOCB_NOWAIT) {

		if (filemap_range_needs_writeback(mapping, pos, end))

			return -EAGAIN;

		return 0;

	}



	return filemap_write_and_wait_range(mapping, pos, end);

}



/**

 * generic_file_read_iter - generic filesystem read routine

 * @iocb:	kernel I/O control block
@@ -2770,18 +2785,9 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) 
		struct address_space *mapping = file->f_mapping;

		struct inode *inode = mapping->host;



		if (iocb->ki_flags & IOCB_NOWAIT) {

			if (filemap_range_needs_writeback(mapping, iocb->ki_pos,

						iocb->ki_pos + count - 1))

				return -EAGAIN;

		} else {

			retval = filemap_write_and_wait_range(mapping,

						iocb->ki_pos,

					        iocb->ki_pos + count - 1);

		retval = kiocb_write_and_wait(iocb, count);

		if (retval < 0)

			return retval;

		}



		file_accessed(file);



		retval = mapping->a_ops->direct_IO(iocb, iter);