1 files changed, 596 insertions, 0 deletions
diff --git a/fs/afs/file.c b/fs/afs/file.c
new file mode 100644
index 000000000..0467742bf
--- /dev/null
+++ b/fs/afs/file.c
@@ -0,0 +1,596 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AFS filesystem file handling
+ *
+ * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/gfp.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/netfs.h>
+#include <trace/events/netfs.h>
+#include "internal.h"
+
+static int afs_file_mmap_prepare(struct vm_area_desc *desc);
+
+static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);
+static ssize_t afs_file_splice_read(struct file *in, loff_t *ppos,
+				    struct pipe_inode_info *pipe,
+				    size_t len, unsigned int flags);
+static void afs_vm_open(struct vm_area_struct *area);
+static void afs_vm_close(struct vm_area_struct *area);
+static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff);
+static int afs_mapped(unsigned long start, unsigned long end, pgoff_t pgoff,
+		      const struct file *file, void **vm_private_data);
+
+const struct file_operations afs_file_operations = {
+	.open		= afs_open,
+	.release	= afs_release,
+	.llseek		= generic_file_llseek,
+	.read_iter	= afs_file_read_iter,
+	.write_iter	= netfs_file_write_iter,
+	.mmap_prepare	= afs_file_mmap_prepare,
+	.splice_read	= afs_file_splice_read,
+	.splice_write	= iter_file_splice_write,
+	.fsync		= afs_fsync,
+	.lock		= afs_lock,
+	.flock		= afs_flock,
+};
+
+const struct inode_operations afs_file_inode_operations = {
+	.getattr	= afs_getattr,
+	.setattr	= afs_setattr,
+	.permission	= afs_permission,
+};
+
+const struct address_space_operations afs_file_aops = {
+	.direct_IO	= noop_direct_IO,
+	.read_folio	= netfs_read_folio,
+	.readahead	= netfs_readahead,
+	.dirty_folio	= netfs_dirty_folio,
+	.release_folio	= netfs_release_folio,
+	.invalidate_folio = netfs_invalidate_folio,
+	.migrate_folio	= filemap_migrate_folio,
+	.writepages	= afs_writepages,
+};
+
+static const struct vm_operations_struct afs_vm_ops = {
+	.mapped		= afs_mapped,
+	.open		= afs_vm_open,
+	.close		= afs_vm_close,
+	.fault		= filemap_fault,
+	.map_pages	= afs_vm_map_pages,
+	.page_mkwrite	= afs_page_mkwrite,
+};
+
+/*
+ * Discard a pin on a writeback key.
+ */
+void afs_put_wb_key(struct afs_wb_key *wbk)
+{
+	if (wbk && refcount_dec_and_test(&wbk->usage)) {
+		key_put(wbk->key);
+		kfree(wbk);
+	}
+}
+
+/*
+ * Cache key for writeback.
+ */
+int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
+{
+	struct afs_wb_key *wbk, *p;
+
+	wbk = kzalloc_obj(struct afs_wb_key);
+	if (!wbk)
+		return -ENOMEM;
+	refcount_set(&wbk->usage, 2);
+	wbk->key = af->key;
+
+	spin_lock(&vnode->wb_lock);
+	list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
+		if (p->key == wbk->key)
+			goto found;
+	}
+
+	key_get(wbk->key);
+	list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
+	spin_unlock(&vnode->wb_lock);
+	af->wb = wbk;
+	return 0;
+
+found:
+	refcount_inc(&p->usage);
+	spin_unlock(&vnode->wb_lock);
+	af->wb = p;
+	kfree(wbk);
+	return 0;
+}
+
+/*
+ * open an AFS file or directory and attach a key to it
+ */
+int afs_open(struct inode *inode, struct file *file)
+{
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	struct afs_file *af;
+	struct key *key;
+	int ret;
+
+	_enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
+
+	key = afs_request_key(vnode->volume->cell);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error;
+	}
+
+	af = kzalloc_obj(*af);
+	if (!af) {
+		ret = -ENOMEM;
+		goto error_key;
+	}
+	af->key = key;
+
+	ret = afs_validate(vnode, key);
+	if (ret < 0)
+		goto error_af;
+
+	if (file->f_mode & FMODE_WRITE) {
+		ret = afs_cache_wb_key(vnode, af);
+		if (ret < 0)
+			goto error_af;
+	}
+
+	if (file->f_flags & O_TRUNC)
+		set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
+
+	fscache_use_cookie(afs_vnode_cache(vnode), file->f_mode & FMODE_WRITE);
+
+	file->private_data = af;
+	_leave(" = 0");
+	return 0;
+
+error_af:
+	kfree(af);
+error_key:
+	key_put(key);
+error:
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * release an AFS file or directory and discard its key
+ */
+int afs_release(struct inode *inode, struct file *file)
+{
+	struct afs_vnode_cache_aux aux;
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	struct afs_file *af = file->private_data;
+	loff_t i_size;
+	int ret = 0;
+
+	_enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
+
+	if ((file->f_mode & FMODE_WRITE))
+		ret = vfs_fsync(file, 0);
+
+	file->private_data = NULL;
+	if (af->wb)
+		afs_put_wb_key(af->wb);
+
+	if ((file->f_mode & FMODE_WRITE)) {
+		i_size = i_size_read(&vnode->netfs.inode);
+		afs_set_cache_aux(vnode, &aux);
+		fscache_unuse_cookie(afs_vnode_cache(vnode), &aux, &i_size);
+	} else {
+		fscache_unuse_cookie(afs_vnode_cache(vnode), NULL, NULL);
+	}
+
+	key_put(af->key);
+	kfree(af);
+	afs_prune_wb_keys(vnode);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+static void afs_fetch_data_notify(struct afs_operation *op)
+{
+	struct netfs_io_subrequest *subreq = op->fetch.subreq;
+
+	subreq->error = afs_op_error(op);
+	netfs_read_subreq_terminated(subreq);
+}
+
+static void afs_fetch_data_success(struct afs_operation *op)
+{
+	struct afs_vnode *vnode = op->file[0].vnode;
+
+	_enter("op=%08x", op->debug_id);
+	afs_vnode_commit_status(op, &op->file[0]);
+	afs_stat_v(vnode, n_fetches);
+	atomic_long_add(op->fetch.subreq->transferred, &op->net->n_fetch_bytes);
+	afs_fetch_data_notify(op);
+}
+
+static void afs_fetch_data_aborted(struct afs_operation *op)
+{
+	afs_check_for_remote_deletion(op);
+	afs_fetch_data_notify(op);
+}
+
+const struct afs_operation_ops afs_fetch_data_operation = {
+	.issue_afs_rpc	= afs_fs_fetch_data,
+	.issue_yfs_rpc	= yfs_fs_fetch_data,
+	.success	= afs_fetch_data_success,
+	.aborted	= afs_fetch_data_aborted,
+	.failed		= afs_fetch_data_notify,
+};
+
+static void afs_issue_read_call(struct afs_operation *op)
+{
+	op->call_responded = false;
+	op->call_error = 0;
+	op->call_abort_code = 0;
+	if (test_bit(AFS_SERVER_FL_IS_YFS, &op->server->flags))
+		yfs_fs_fetch_data(op);
+	else
+		afs_fs_fetch_data(op);
+}
+
+static void afs_end_read(struct afs_operation *op)
+{
+	if (op->call_responded && op->server)
+		set_bit(AFS_SERVER_FL_RESPONDING, &op->server->flags);
+
+	if (!afs_op_error(op))
+		afs_fetch_data_success(op);
+	else if (op->cumul_error.aborted)
+		afs_fetch_data_aborted(op);
+	else
+		afs_fetch_data_notify(op);
+
+	afs_end_vnode_operation(op);
+	afs_put_operation(op);
+}
+
+/*
+ * Perform I/O processing on an asynchronous call.  The work item carries a ref
+ * to the call struct that we either need to release or to pass on.
+ */
+static void afs_read_receive(struct afs_call *call)
+{
+	struct afs_operation *op = call->op;
+	enum afs_call_state state;
+
+	_enter("");
+
+	state = READ_ONCE(call->state);
+	if (state == AFS_CALL_COMPLETE)
+		return;
+	trace_afs_read_recv(op, call);
+
+	while (state < AFS_CALL_COMPLETE && READ_ONCE(call->need_attention)) {
+		WRITE_ONCE(call->need_attention, false);
+		afs_deliver_to_call(call);
+		state = READ_ONCE(call->state);
+	}
+
+	if (state < AFS_CALL_COMPLETE) {
+		netfs_read_subreq_progress(op->fetch.subreq);
+		if (rxrpc_kernel_check_life(call->net->socket, call->rxcall))
+			return;
+		/* rxrpc terminated the call. */
+		afs_set_call_complete(call, call->error, call->abort_code);
+	}
+
+	op->call_abort_code	= call->abort_code;
+	op->call_error		= call->error;
+	op->call_responded	= call->responded;
+	op->call		= NULL;
+	call->op		= NULL;
+	afs_put_call(call);
+
+	/* If the call failed, then we need to crank the server rotation
+	 * handle and try the next.
+	 */
+	if (afs_select_fileserver(op)) {
+		afs_issue_read_call(op);
+		return;
+	}
+
+	afs_end_read(op);
+}
+
+void afs_fetch_data_async_rx(struct work_struct *work)
+{
+	struct afs_call *call = container_of(work, struct afs_call, async_work);
+
+	afs_read_receive(call);
+	afs_put_call(call);
+}
+
+void afs_fetch_data_immediate_cancel(struct afs_call *call)
+{
+	if (call->async) {
+		afs_get_call(call, afs_call_trace_wake);
+		if (!queue_work(afs_async_calls, &call->async_work))
+			afs_deferred_put_call(call);
+		flush_work(&call->async_work);
+	}
+}
+
+/*
+ * Fetch file data from the volume.
+ */
+static void afs_issue_read(struct netfs_io_subrequest *subreq)
+{
+	struct afs_operation *op;
+	struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
+	struct key *key = subreq->rreq->netfs_priv;
+
+	_enter("%s{%llx:%llu.%u},%x,,,",
+	       vnode->volume->name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       key_serial(key));
+
+	op = afs_alloc_operation(key, vnode->volume);
+	if (IS_ERR(op)) {
+		subreq->error = PTR_ERR(op);
+		netfs_read_subreq_terminated(subreq);
+		return;
+	}
+
+	afs_op_set_vnode(op, 0, vnode);
+
+	op->fetch.subreq = subreq;
+	op->ops		= &afs_fetch_data_operation;
+
+	trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
+
+	if (subreq->rreq->origin == NETFS_READAHEAD ||
+	    subreq->rreq->iocb) {
+		op->flags |= AFS_OPERATION_ASYNC;
+
+		if (!afs_begin_vnode_operation(op)) {
+			subreq->error = afs_put_operation(op);
+			netfs_read_subreq_terminated(subreq);
+			return;
+		}
+
+		if (!afs_select_fileserver(op)) {
+			afs_end_read(op);
+			return;
+		}
+
+		afs_issue_read_call(op);
+	} else {
+		afs_do_sync_operation(op);
+	}
+}
+
+static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
+{
+	struct afs_vnode *vnode = AFS_FS_I(rreq->inode);
+
+	if (file)
+		rreq->netfs_priv = key_get(afs_file_key(file));
+	rreq->rsize = 256 * 1024;
+	rreq->wsize = 256 * 1024 * 1024;
+
+	switch (rreq->origin) {
+	case NETFS_READ_SINGLE:
+		if (!file) {
+			struct key *key = afs_request_key(vnode->volume->cell);
+
+			if (IS_ERR(key))
+				return PTR_ERR(key);
+			rreq->netfs_priv = key;
+		}
+		break;
+	case NETFS_WRITEBACK:
+	case NETFS_WRITETHROUGH:
+	case NETFS_UNBUFFERED_WRITE:
+	case NETFS_DIO_WRITE:
+		if (S_ISREG(rreq->inode->i_mode))
+			rreq->io_streams[0].avail = true;
+		break;
+	case NETFS_WRITEBACK_SINGLE:
+	default:
+		break;
+	}
+	return 0;
+}
+
+static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
+				 struct folio **foliop, void **_fsdata)
+{
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
+
+	return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0;
+}
+
+static void afs_free_request(struct netfs_io_request *rreq)
+{
+	key_put(rreq->netfs_priv);
+	afs_put_wb_key(rreq->netfs_priv2);
+}
+
+/*
+ * Set the file size and block count, taking ->cb_lock and ->i_lock to maintain
+ * coherency and prevent 64-bit tearing on 32-bit arches.
+ *
+ * Also, estimate the number of 512 bytes blocks used, rounded up to nearest 1K
+ * for consistency with other AFS clients.
+ */
+void afs_set_i_size(struct afs_vnode *vnode, loff_t new_i_size)
+{
+	struct inode *inode = &vnode->netfs.inode;
+	loff_t i_size;
+
+	write_seqlock(&vnode->cb_lock);
+	spin_lock(&inode->i_lock);
+	i_size = i_size_read(inode);
+	if (new_i_size > i_size) {
+		i_size_write(inode, new_i_size);
+		inode_set_bytes(inode, round_up(new_i_size, 1024));
+	}
+	spin_unlock(&inode->i_lock);
+	write_sequnlock(&vnode->cb_lock);
+	fscache_update_cookie(afs_vnode_cache(vnode), NULL, &new_i_size);
+}
+
+static void afs_update_i_size(struct inode *inode, loff_t new_i_size)
+{
+	afs_set_i_size(AFS_FS_I(inode), new_i_size);
+}
+
+static void afs_netfs_invalidate_cache(struct netfs_io_request *wreq)
+{
+	struct afs_vnode *vnode = AFS_FS_I(wreq->inode);
+
+	afs_invalidate_cache(vnode, 0);
+}
+
+const struct netfs_request_ops afs_req_ops = {
+	.init_request		= afs_init_request,
+	.free_request		= afs_free_request,
+	.check_write_begin	= afs_check_write_begin,
+	.issue_read		= afs_issue_read,
+	.update_i_size		= afs_update_i_size,
+	.invalidate_cache	= afs_netfs_invalidate_cache,
+	.begin_writeback	= afs_begin_writeback,
+	.prepare_write		= afs_prepare_write,
+	.issue_write		= afs_issue_write,
+	.retry_request		= afs_retry_request,
+};
+
+static void afs_add_open_mmap(struct afs_vnode *vnode)
+{
+	if (atomic_inc_return(&vnode->cb_nr_mmap) == 1) {
+		down_write(&vnode->volume->open_mmaps_lock);
+
+		if (list_empty(&vnode->cb_mmap_link))
+			list_add_tail(&vnode->cb_mmap_link, &vnode->volume->open_mmaps);
+
+		up_write(&vnode->volume->open_mmaps_lock);
+	}
+}
+
+static void afs_drop_open_mmap(struct afs_vnode *vnode)
+{
+	if (atomic_add_unless(&vnode->cb_nr_mmap, -1, 1))
+		return;
+
+	down_write(&vnode->volume->open_mmaps_lock);
+
+	read_seqlock_excl(&vnode->cb_lock);
+	// the only place where ->cb_nr_mmap may hit 0
+	// see __afs_break_callback() for the other side...
+	if (atomic_dec_and_test(&vnode->cb_nr_mmap))
+		list_del_init(&vnode->cb_mmap_link);
+	read_sequnlock_excl(&vnode->cb_lock);
+
+	up_write(&vnode->volume->open_mmaps_lock);
+	flush_work(&vnode->cb_work);
+}
+
+/*
+ * Handle setting up a memory mapping on an AFS file.
+ */
+static int afs_file_mmap_prepare(struct vm_area_desc *desc)
+{
+	int ret;
+
+	ret = generic_file_mmap_prepare(desc);
+	if (ret)
+		return ret;
+
+	desc->vm_ops = &afs_vm_ops;
+	return ret;
+}
+
+static int afs_mapped(unsigned long start, unsigned long end, pgoff_t pgoff,
+		      const struct file *file, void **vm_private_data)
+{
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
+
+	afs_add_open_mmap(vnode);
+	return 0;
+}
+
+static void afs_vm_open(struct vm_area_struct *vma)
+{
+	struct file *file = vma->vm_file;
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
+
+	afs_add_open_mmap(vnode);
+}
+
+static void afs_vm_close(struct vm_area_struct *vma)
+{
+	struct file *file = vma->vm_file;
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
+
+	afs_drop_open_mmap(vnode);
+}
+
+static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff)
+{
+	struct file *file = vmf->vma->vm_file;
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
+
+	if (afs_check_validity(vnode))
+		return filemap_map_pages(vmf, start_pgoff, end_pgoff);
+	return 0;
+}
+
+static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	struct afs_file *af = iocb->ki_filp->private_data;
+	ssize_t ret;
+
+	if (iocb->ki_flags & IOCB_DIRECT)
+		return netfs_unbuffered_read_iter(iocb, iter);
+
+	ret = netfs_start_io_read(inode);
+	if (ret < 0)
+		return ret;
+	ret = afs_validate(vnode, af->key);
+	if (ret == 0)
+		ret = filemap_read(iocb, iter, 0);
+	netfs_end_io_read(inode);
+	return ret;
+}
+
+static ssize_t afs_file_splice_read(struct file *in, loff_t *ppos,
+				    struct pipe_inode_info *pipe,
+				    size_t len, unsigned int flags)
+{
+	struct inode *inode = file_inode(in);
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	struct afs_file *af = in->private_data;
+	ssize_t ret;
+
+	ret = netfs_start_io_read(inode);
+	if (ret < 0)
+		return ret;
+	ret = afs_validate(vnode, af->key);
+	if (ret == 0)
+		ret = filemap_splice_read(in, ppos, pipe, len, flags);
+	netfs_end_io_read(inode);
+	return ret;
+}