cachefiles: Delete the cachefiles driver pending rewrite

Delete the code from the cachefiles driver to make it easier to rewrite and
resubmit in a logical manner.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819577641.215744.12718114397770666596.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906883770.143852.4149714614981373410.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967076066.1823006.7175712134577687753.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021483619.640689.7586546280515844702.stgit@warthog.procyon.org.uk/ # v4

1 files changed, 0 insertions, 420 deletions

diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
deleted file mode 100644
index effe37ef8629..000000000000
--- a/fs/cachefiles/io.c
+++ /dev/null
@@ -1,420 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* kiocb-using read/write
- *
- * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- */
-
-#include <linux/mount.h>
-#include <linux/slab.h>
-#include <linux/file.h>
-#include <linux/uio.h>
-#include <linux/sched/mm.h>
-#include <linux/netfs.h>
-#include "internal.h"
-
-struct cachefiles_kiocb {
-	struct kiocb		iocb;
-	refcount_t		ki_refcnt;
-	loff_t			start;
-	union {
-		size_t		skipped;
-		size_t		len;
-	};
-	netfs_io_terminated_t	term_func;
-	void			*term_func_priv;
-	bool			was_async;
-};
-
-static inline void cachefiles_put_kiocb(struct cachefiles_kiocb *ki)
-{
-	if (refcount_dec_and_test(&ki->ki_refcnt)) {
-		fput(ki->iocb.ki_filp);
-		kfree(ki);
-	}
-}
-
-/*
- * Handle completion of a read from the cache.
- */
-static void cachefiles_read_complete(struct kiocb *iocb, long ret)
-{
-	struct cachefiles_kiocb *ki = container_of(iocb, struct cachefiles_kiocb, iocb);
-
-	_enter("%ld", ret);
-
-	if (ki->term_func) {
-		if (ret >= 0)
-			ret += ki->skipped;
-		ki->term_func(ki->term_func_priv, ret, ki->was_async);
-	}
-
-	cachefiles_put_kiocb(ki);
-}
-
-/*
- * Initiate a read from the cache.
- */
-static int cachefiles_read(struct netfs_cache_resources *cres,
-			   loff_t start_pos,
-			   struct iov_iter *iter,
-			   bool seek_data,
-			   netfs_io_terminated_t term_func,
-			   void *term_func_priv)
-{
-	struct cachefiles_kiocb *ki;
-	struct file *file = cres->cache_priv2;
-	unsigned int old_nofs;
-	ssize_t ret = -ENOBUFS;
-	size_t len = iov_iter_count(iter), skipped = 0;
-
-	_enter("%pD,%li,%llx,%zx/%llx",
-	       file, file_inode(file)->i_ino, start_pos, len,
-	       i_size_read(file_inode(file)));
-
-	/* If the caller asked us to seek for data before doing the read, then
-	 * we should do that now.  If we find a gap, we fill it with zeros.
-	 */
-	if (seek_data) {
-		loff_t off = start_pos, off2;
-
-		off2 = vfs_llseek(file, off, SEEK_DATA);
-		if (off2 < 0 && off2 >= (loff_t)-MAX_ERRNO && off2 != -ENXIO) {
-			skipped = 0;
-			ret = off2;
-			goto presubmission_error;
-		}
-
-		if (off2 == -ENXIO || off2 >= start_pos + len) {
-			/* The region is beyond the EOF or there's no more data
-			 * in the region, so clear the rest of the buffer and
-			 * return success.
-			 */
-			iov_iter_zero(len, iter);
-			skipped = len;
-			ret = 0;
-			goto presubmission_error;
-		}
-
-		skipped = off2 - off;
-		iov_iter_zero(skipped, iter);
-	}
-
-	ret = -ENOBUFS;
-	ki = kzalloc(sizeof(struct cachefiles_kiocb), GFP_KERNEL);
-	if (!ki)
-		goto presubmission_error;
-
-	refcount_set(&ki->ki_refcnt, 2);
-	ki->iocb.ki_filp	= file;
-	ki->iocb.ki_pos		= start_pos + skipped;
-	ki->iocb.ki_flags	= IOCB_DIRECT;
-	ki->iocb.ki_hint	= ki_hint_validate(file_write_hint(file));
-	ki->iocb.ki_ioprio	= get_current_ioprio();
-	ki->skipped		= skipped;
-	ki->term_func		= term_func;
-	ki->term_func_priv	= term_func_priv;
-	ki->was_async		= true;
-
-	if (ki->term_func)
-		ki->iocb.ki_complete = cachefiles_read_complete;
-
-	get_file(ki->iocb.ki_filp);
-
-	old_nofs = memalloc_nofs_save();
-	ret = vfs_iocb_iter_read(file, &ki->iocb, iter);
-	memalloc_nofs_restore(old_nofs);
-	switch (ret) {
-	case -EIOCBQUEUED:
-		goto in_progress;
-
-	case -ERESTARTSYS:
-	case -ERESTARTNOINTR:
-	case -ERESTARTNOHAND:
-	case -ERESTART_RESTARTBLOCK:
-		/* There's no easy way to restart the syscall since other AIO's
-		 * may be already running. Just fail this IO with EINTR.
-		 */
-		ret = -EINTR;
-		fallthrough;
-	default:
-		ki->was_async = false;
-		cachefiles_read_complete(&ki->iocb, ret);
-		if (ret > 0)
-			ret = 0;
-		break;
-	}
-
-in_progress:
-	cachefiles_put_kiocb(ki);
-	_leave(" = %zd", ret);
-	return ret;
-
-presubmission_error:
-	if (term_func)
-		term_func(term_func_priv, ret < 0 ? ret : skipped, false);
-	return ret;
-}
-
-/*
- * Handle completion of a write to the cache.
- */
-static void cachefiles_write_complete(struct kiocb *iocb, long ret)
-{
-	struct cachefiles_kiocb *ki = container_of(iocb, struct cachefiles_kiocb, iocb);
-	struct inode *inode = file_inode(ki->iocb.ki_filp);
-
-	_enter("%ld", ret);
-
-	/* Tell lockdep we inherited freeze protection from submission thread */
-	__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
-	__sb_end_write(inode->i_sb, SB_FREEZE_WRITE);
-
-	if (ki->term_func)
-		ki->term_func(ki->term_func_priv, ret, ki->was_async);
-
-	cachefiles_put_kiocb(ki);
-}
-
-/*
- * Initiate a write to the cache.
- */
-static int cachefiles_write(struct netfs_cache_resources *cres,
-			    loff_t start_pos,
-			    struct iov_iter *iter,
-			    netfs_io_terminated_t term_func,
-			    void *term_func_priv)
-{
-	struct cachefiles_kiocb *ki;
-	struct inode *inode;
-	struct file *file = cres->cache_priv2;
-	unsigned int old_nofs;
-	ssize_t ret = -ENOBUFS;
-	size_t len = iov_iter_count(iter);
-
-	_enter("%pD,%li,%llx,%zx/%llx",
-	       file, file_inode(file)->i_ino, start_pos, len,
-	       i_size_read(file_inode(file)));
-
-	ki = kzalloc(sizeof(struct cachefiles_kiocb), GFP_KERNEL);
-	if (!ki)
-		goto presubmission_error;
-
-	refcount_set(&ki->ki_refcnt, 2);
-	ki->iocb.ki_filp	= file;
-	ki->iocb.ki_pos		= start_pos;
-	ki->iocb.ki_flags	= IOCB_DIRECT | IOCB_WRITE;
-	ki->iocb.ki_hint	= ki_hint_validate(file_write_hint(file));
-	ki->iocb.ki_ioprio	= get_current_ioprio();
-	ki->start		= start_pos;
-	ki->len			= len;
-	ki->term_func		= term_func;
-	ki->term_func_priv	= term_func_priv;
-	ki->was_async		= true;
-
-	if (ki->term_func)
-		ki->iocb.ki_complete = cachefiles_write_complete;
-
-	/* Open-code file_start_write here to grab freeze protection, which
-	 * will be released by another thread in aio_complete_rw().  Fool
-	 * lockdep by telling it the lock got released so that it doesn't
-	 * complain about the held lock when we return to userspace.
-	 */
-	inode = file_inode(file);
-	__sb_start_write(inode->i_sb, SB_FREEZE_WRITE);
-	__sb_writers_release(inode->i_sb, SB_FREEZE_WRITE);
-
-	get_file(ki->iocb.ki_filp);
-
-	old_nofs = memalloc_nofs_save();
-	ret = vfs_iocb_iter_write(file, &ki->iocb, iter);
-	memalloc_nofs_restore(old_nofs);
-	switch (ret) {
-	case -EIOCBQUEUED:
-		goto in_progress;
-
-	case -ERESTARTSYS:
-	case -ERESTARTNOINTR:
-	case -ERESTARTNOHAND:
-	case -ERESTART_RESTARTBLOCK:
-		/* There's no easy way to restart the syscall since other AIO's
-		 * may be already running. Just fail this IO with EINTR.
-		 */
-		ret = -EINTR;
-		fallthrough;
-	default:
-		ki->was_async = false;
-		cachefiles_write_complete(&ki->iocb, ret);
-		if (ret > 0)
-			ret = 0;
-		break;
-	}
-
-in_progress:
-	cachefiles_put_kiocb(ki);
-	_leave(" = %zd", ret);
-	return ret;
-
-presubmission_error:
-	if (term_func)
-		term_func(term_func_priv, -ENOMEM, false);
-	return -ENOMEM;
-}
-
-/*
- * Prepare a read operation, shortening it to a cached/uncached
- * boundary as appropriate.
- */
-static enum netfs_read_source cachefiles_prepare_read(struct netfs_read_subrequest *subreq,
-						      loff_t i_size)
-{
-	struct fscache_retrieval *op = subreq->rreq->cache_resources.cache_priv;
-	struct cachefiles_object *object;
-	struct cachefiles_cache *cache;
-	const struct cred *saved_cred;
-	struct file *file = subreq->rreq->cache_resources.cache_priv2;
-	loff_t off, to;
-
-	_enter("%zx @%llx/%llx", subreq->len, subreq->start, i_size);
-
-	object = container_of(op->op.object,
-			      struct cachefiles_object, fscache);
-	cache = container_of(object->fscache.cache,
-			     struct cachefiles_cache, cache);
-
-	if (!file)
-		goto cache_fail_nosec;
-
-	if (subreq->start >= i_size)
-		return NETFS_FILL_WITH_ZEROES;
-
-	cachefiles_begin_secure(cache, &saved_cred);
-
-	off = vfs_llseek(file, subreq->start, SEEK_DATA);
-	if (off < 0 && off >= (loff_t)-MAX_ERRNO) {
-		if (off == (loff_t)-ENXIO)
-			goto download_and_store;
-		goto cache_fail;
-	}
-
-	if (off >= subreq->start + subreq->len)
-		goto download_and_store;
-
-	if (off > subreq->start) {
-		off = round_up(off, cache->bsize);
-		subreq->len = off - subreq->start;
-		goto download_and_store;
-	}
-
-	to = vfs_llseek(file, subreq->start, SEEK_HOLE);
-	if (to < 0 && to >= (loff_t)-MAX_ERRNO)
-		goto cache_fail;
-
-	if (to < subreq->start + subreq->len) {
-		if (subreq->start + subreq->len >= i_size)
-			to = round_up(to, cache->bsize);
-		else
-			to = round_down(to, cache->bsize);
-		subreq->len = to - subreq->start;
-	}
-
-	cachefiles_end_secure(cache, saved_cred);
-	return NETFS_READ_FROM_CACHE;
-
-download_and_store:
-	if (cachefiles_has_space(cache, 0, (subreq->len + PAGE_SIZE - 1) / PAGE_SIZE) == 0)
-		__set_bit(NETFS_SREQ_WRITE_TO_CACHE, &subreq->flags);
-cache_fail:
-	cachefiles_end_secure(cache, saved_cred);
-cache_fail_nosec:
-	return NETFS_DOWNLOAD_FROM_SERVER;
-}
-
-/*
- * Prepare for a write to occur.
- */
-static int cachefiles_prepare_write(struct netfs_cache_resources *cres,
-				    loff_t *_start, size_t *_len, loff_t i_size)
-{
-	loff_t start = *_start;
-	size_t len = *_len, down;
-
-	/* Round to DIO size */
-	down = start - round_down(start, PAGE_SIZE);
-	*_start = start - down;
-	*_len = round_up(down + len, PAGE_SIZE);
-	return 0;
-}
-
-/*
- * Clean up an operation.
- */
-static void cachefiles_end_operation(struct netfs_cache_resources *cres)
-{
-	struct fscache_retrieval *op = cres->cache_priv;
-	struct file *file = cres->cache_priv2;
-
-	_enter("");
-
-	if (file)
-		fput(file);
-	if (op) {
-		fscache_op_complete(&op->op, false);
-		fscache_put_retrieval(op);
-	}
-
-	_leave("");
-}
-
-static const struct netfs_cache_ops cachefiles_netfs_cache_ops = {
-	.end_operation		= cachefiles_end_operation,
-	.read			= cachefiles_read,
-	.write			= cachefiles_write,
-	.prepare_read		= cachefiles_prepare_read,
-	.prepare_write		= cachefiles_prepare_write,
-};
-
-/*
- * Open the cache file when beginning a cache operation.
- */
-int cachefiles_begin_read_operation(struct netfs_read_request *rreq,
-				    struct fscache_retrieval *op)
-{
-	struct cachefiles_object *object;
-	struct cachefiles_cache *cache;
-	struct path path;
-	struct file *file;
-
-	_enter("");
-
-	object = container_of(op->op.object,
-			      struct cachefiles_object, fscache);
-	cache = container_of(object->fscache.cache,
-			     struct cachefiles_cache, cache);
-
-	path.mnt = cache->mnt;
-	path.dentry = object->backer;
-	file = open_with_fake_path(&path, O_RDWR | O_LARGEFILE | O_DIRECT,
-				   d_inode(object->backer), cache->cache_cred);
-	if (IS_ERR(file))
-		return PTR_ERR(file);
-	if (!S_ISREG(file_inode(file)->i_mode))
-		goto error_file;
-	if (unlikely(!file->f_op->read_iter) ||
-	    unlikely(!file->f_op->write_iter)) {
-		pr_notice("Cache does not support read_iter and write_iter\n");
-		goto error_file;
-	}
-
-	fscache_get_retrieval(op);
-	rreq->cache_resources.cache_priv = op;
-	rreq->cache_resources.cache_priv2 = file;
-	rreq->cache_resources.ops = &cachefiles_netfs_cache_ops;
-	rreq->cache_resources.debug_id = object->fscache.debug_id;
-	_leave("");
-	return 0;
-
-error_file:
-	fput(file);
-	return -EIO;
-}