1 files changed, 598 insertions, 0 deletions
diff --git a/fs/afs/file.c b/fs/afs/file.c
new file mode 100644
index 000000000..2eeab57df
--- /dev/null
+++ b/fs/afs/file.c
@@ -0,0 +1,598 @@
+// 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 "internal.h"
+
+static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
+static int afs_symlink_read_folio(struct file *file, struct folio *folio);
+static void afs_invalidate_folio(struct folio *folio, size_t offset,
+			       size_t length);
+static bool afs_release_folio(struct folio *folio, gfp_t gfp_flags);
+
+static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);
+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);
+
+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	= afs_file_write,
+	.mmap		= afs_file_mmap,
+	.splice_read	= generic_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 = {
+	.read_folio	= netfs_read_folio,
+	.readahead	= netfs_readahead,
+	.dirty_folio	= afs_dirty_folio,
+	.launder_folio	= afs_launder_folio,
+	.release_folio	= afs_release_folio,
+	.invalidate_folio = afs_invalidate_folio,
+	.write_begin	= afs_write_begin,
+	.write_end	= afs_write_end,
+	.writepage	= afs_writepage,
+	.writepages	= afs_writepages,
+};
+
+const struct address_space_operations afs_symlink_aops = {
+	.read_folio	= afs_symlink_read_folio,
+	.release_folio	= afs_release_folio,
+	.invalidate_folio = afs_invalidate_folio,
+};
+
+static const struct vm_operations_struct afs_vm_ops = {
+	.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(sizeof(struct afs_wb_key), GFP_KERNEL);
+	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(sizeof(*af), GFP_KERNEL);
+	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;
+}
+
+/*
+ * Allocate a new read record.
+ */
+struct afs_read *afs_alloc_read(gfp_t gfp)
+{
+	struct afs_read *req;
+
+	req = kzalloc(sizeof(struct afs_read), gfp);
+	if (req)
+		refcount_set(&req->usage, 1);
+
+	return req;
+}
+
+/*
+ * Dispose of a ref to a read record.
+ */
+void afs_put_read(struct afs_read *req)
+{
+	if (refcount_dec_and_test(&req->usage)) {
+		if (req->cleanup)
+			req->cleanup(req);
+		key_put(req->key);
+		kfree(req);
+	}
+}
+
+static void afs_fetch_data_notify(struct afs_operation *op)
+{
+	struct afs_read *req = op->fetch.req;
+	struct netfs_io_subrequest *subreq = req->subreq;
+	int error = op->error;
+
+	if (error == -ECONNABORTED)
+		error = afs_abort_to_error(op->ac.abort_code);
+	req->error = error;
+
+	if (subreq) {
+		__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+		netfs_subreq_terminated(subreq, error ?: req->actual_len, false);
+		req->subreq = NULL;
+	} else if (req->done) {
+		req->done(req);
+	}
+}
+
+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.req->actual_len, &op->net->n_fetch_bytes);
+	afs_fetch_data_notify(op);
+}
+
+static void afs_fetch_data_put(struct afs_operation *op)
+{
+	op->fetch.req->error = op->error;
+	afs_put_read(op->fetch.req);
+}
+
+static 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_check_for_remote_deletion,
+	.failed		= afs_fetch_data_notify,
+	.put		= afs_fetch_data_put,
+};
+
+/*
+ * Fetch file data from the volume.
+ */
+int afs_fetch_data(struct afs_vnode *vnode, struct afs_read *req)
+{
+	struct afs_operation *op;
+
+	_enter("%s{%llx:%llu.%u},%x,,,",
+	       vnode->volume->name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       key_serial(req->key));
+
+	op = afs_alloc_operation(req->key, vnode->volume);
+	if (IS_ERR(op)) {
+		if (req->subreq)
+			netfs_subreq_terminated(req->subreq, PTR_ERR(op), false);
+		return PTR_ERR(op);
+	}
+
+	afs_op_set_vnode(op, 0, vnode);
+
+	op->fetch.req	= afs_get_read(req);
+	op->ops		= &afs_fetch_data_operation;
+	return afs_do_sync_operation(op);
+}
+
+static void afs_issue_read(struct netfs_io_subrequest *subreq)
+{
+	struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
+	struct afs_read *fsreq;
+
+	fsreq = afs_alloc_read(GFP_NOFS);
+	if (!fsreq)
+		return netfs_subreq_terminated(subreq, -ENOMEM, false);
+
+	fsreq->subreq	= subreq;
+	fsreq->pos	= subreq->start + subreq->transferred;
+	fsreq->len	= subreq->len   - subreq->transferred;
+	fsreq->key	= key_get(subreq->rreq->netfs_priv);
+	fsreq->vnode	= vnode;
+	fsreq->iter	= &fsreq->def_iter;
+
+	iov_iter_xarray(&fsreq->def_iter, ITER_DEST,
+			&fsreq->vnode->netfs.inode.i_mapping->i_pages,
+			fsreq->pos, fsreq->len);
+
+	afs_fetch_data(fsreq->vnode, fsreq);
+	afs_put_read(fsreq);
+}
+
+static int afs_symlink_read_folio(struct file *file, struct folio *folio)
+{
+	struct afs_vnode *vnode = AFS_FS_I(folio->mapping->host);
+	struct afs_read *fsreq;
+	int ret;
+
+	fsreq = afs_alloc_read(GFP_NOFS);
+	if (!fsreq)
+		return -ENOMEM;
+
+	fsreq->pos	= folio_pos(folio);
+	fsreq->len	= folio_size(folio);
+	fsreq->vnode	= vnode;
+	fsreq->iter	= &fsreq->def_iter;
+	iov_iter_xarray(&fsreq->def_iter, ITER_DEST, &folio->mapping->i_pages,
+			fsreq->pos, fsreq->len);
+
+	ret = afs_fetch_data(fsreq->vnode, fsreq);
+	if (ret == 0)
+		folio_mark_uptodate(folio);
+	folio_unlock(folio);
+	return ret;
+}
+
+static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
+{
+	rreq->netfs_priv = key_get(afs_file_key(file));
+	return 0;
+}
+
+static int afs_begin_cache_operation(struct netfs_io_request *rreq)
+{
+#ifdef CONFIG_AFS_FSCACHE
+	struct afs_vnode *vnode = AFS_FS_I(rreq->inode);
+
+	return fscache_begin_read_operation(&rreq->cache_resources,
+					    afs_vnode_cache(vnode));
+#else
+	return -ENOBUFS;
+#endif
+}
+
+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);
+}
+
+const struct netfs_request_ops afs_req_ops = {
+	.init_request		= afs_init_request,
+	.free_request		= afs_free_request,
+	.begin_cache_operation	= afs_begin_cache_operation,
+	.check_write_begin	= afs_check_write_begin,
+	.issue_read		= afs_issue_read,
+};
+
+int afs_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	fscache_unpin_writeback(wbc, afs_vnode_cache(AFS_FS_I(inode)));
+	return 0;
+}
+
+/*
+ * Adjust the dirty region of the page on truncation or full invalidation,
+ * getting rid of the markers altogether if the region is entirely invalidated.
+ */
+static void afs_invalidate_dirty(struct folio *folio, size_t offset,
+				 size_t length)
+{
+	struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
+	unsigned long priv;
+	unsigned int f, t, end = offset + length;
+
+	priv = (unsigned long)folio_get_private(folio);
+
+	/* we clean up only if the entire page is being invalidated */
+	if (offset == 0 && length == folio_size(folio))
+		goto full_invalidate;
+
+	 /* If the page was dirtied by page_mkwrite(), the PTE stays writable
+	  * and we don't get another notification to tell us to expand it
+	  * again.
+	  */
+	if (afs_is_folio_dirty_mmapped(priv))
+		return;
+
+	/* We may need to shorten the dirty region */
+	f = afs_folio_dirty_from(folio, priv);
+	t = afs_folio_dirty_to(folio, priv);
+
+	if (t <= offset || f >= end)
+		return; /* Doesn't overlap */
+
+	if (f < offset && t > end)
+		return; /* Splits the dirty region - just absorb it */
+
+	if (f >= offset && t <= end)
+		goto undirty;
+
+	if (f < offset)
+		t = offset;
+	else
+		f = end;
+	if (f == t)
+		goto undirty;
+
+	priv = afs_folio_dirty(folio, f, t);
+	folio_change_private(folio, (void *)priv);
+	trace_afs_folio_dirty(vnode, tracepoint_string("trunc"), folio);
+	return;
+
+undirty:
+	trace_afs_folio_dirty(vnode, tracepoint_string("undirty"), folio);
+	folio_clear_dirty_for_io(folio);
+full_invalidate:
+	trace_afs_folio_dirty(vnode, tracepoint_string("inval"), folio);
+	folio_detach_private(folio);
+}
+
+/*
+ * invalidate part or all of a page
+ * - release a page and clean up its private data if offset is 0 (indicating
+ *   the entire page)
+ */
+static void afs_invalidate_folio(struct folio *folio, size_t offset,
+			       size_t length)
+{
+	_enter("{%lu},%zu,%zu", folio->index, offset, length);
+
+	BUG_ON(!folio_test_locked(folio));
+
+	if (folio_get_private(folio))
+		afs_invalidate_dirty(folio, offset, length);
+
+	folio_wait_fscache(folio);
+	_leave("");
+}
+
+/*
+ * release a page and clean up its private state if it's not busy
+ * - return true if the page can now be released, false if not
+ */
+static bool afs_release_folio(struct folio *folio, gfp_t gfp)
+{
+	struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
+
+	_enter("{{%llx:%llu}[%lu],%lx},%x",
+	       vnode->fid.vid, vnode->fid.vnode, folio_index(folio), folio->flags,
+	       gfp);
+
+	/* deny if folio is being written to the cache and the caller hasn't
+	 * elected to wait */
+#ifdef CONFIG_AFS_FSCACHE
+	if (folio_test_fscache(folio)) {
+		if (current_is_kswapd() || !(gfp & __GFP_FS))
+			return false;
+		folio_wait_fscache(folio);
+	}
+	fscache_note_page_release(afs_vnode_cache(vnode));
+#endif
+
+	if (folio_test_private(folio)) {
+		trace_afs_folio_dirty(vnode, tracepoint_string("rel"), folio);
+		folio_detach_private(folio);
+	}
+
+	/* Indicate that the folio can be released */
+	_leave(" = T");
+	return true;
+}
+
+static void afs_add_open_mmap(struct afs_vnode *vnode)
+{
+	if (atomic_inc_return(&vnode->cb_nr_mmap) == 1) {
+		down_write(&vnode->volume->cell->fs_open_mmaps_lock);
+
+		if (list_empty(&vnode->cb_mmap_link))
+			list_add_tail(&vnode->cb_mmap_link,
+				      &vnode->volume->cell->fs_open_mmaps);
+
+		up_write(&vnode->volume->cell->fs_open_mmaps_lock);
+	}
+}
+
+static void afs_drop_open_mmap(struct afs_vnode *vnode)
+{
+	if (!atomic_dec_and_test(&vnode->cb_nr_mmap))
+		return;
+
+	down_write(&vnode->volume->cell->fs_open_mmaps_lock);
+
+	if (atomic_read(&vnode->cb_nr_mmap) == 0)
+		list_del_init(&vnode->cb_mmap_link);
+
+	up_write(&vnode->volume->cell->fs_open_mmaps_lock);
+	flush_work(&vnode->cb_work);
+}
+
+/*
+ * Handle setting up a memory mapping on an AFS file.
+ */
+static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
+	int ret;
+
+	afs_add_open_mmap(vnode);
+
+	ret = generic_file_mmap(file, vma);
+	if (ret == 0)
+		vma->vm_ops = &afs_vm_ops;
+	else
+		afs_drop_open_mmap(vnode);
+	return ret;
+}
+
+static void afs_vm_open(struct vm_area_struct *vma)
+{
+	afs_add_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
+}
+
+static void afs_vm_close(struct vm_area_struct *vma)
+{
+	afs_drop_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
+}
+
+static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff)
+{
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(vmf->vma->vm_file));
+	struct afs_file *af = vmf->vma->vm_file->private_data;
+
+	switch (afs_validate(vnode, af->key)) {
+	case 0:
+		return filemap_map_pages(vmf, start_pgoff, end_pgoff);
+	case -ENOMEM:
+		return VM_FAULT_OOM;
+	case -EINTR:
+	case -ERESTARTSYS:
+		return VM_FAULT_RETRY;
+	case -ESTALE:
+	default:
+		return VM_FAULT_SIGBUS;
+	}
+}
+
+static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
+	struct afs_file *af = iocb->ki_filp->private_data;
+	int ret;
+
+	ret = afs_validate(vnode, af->key);
+	if (ret < 0)
+		return ret;
+
+	return generic_file_read_iter(iocb, iter);
+}