1 files changed, 534 insertions, 0 deletions
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
new file mode 100644
index 000000000..cddfb4b7c
--- /dev/null
+++ b/fs/9p/vfs_file.c
@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file contians vfs file ops for 9P2000.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/filelock.h>
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <linux/pagemap.h>
+#include <linux/utsname.h>
+#include <linux/uaccess.h>
+#include <linux/uio.h>
+#include <linux/slab.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+#include "cache.h"
+
+static const struct vm_operations_struct v9fs_mmap_file_vm_ops;
+
+/**
+ * v9fs_file_open - open a file (or directory)
+ * @inode: inode to be opened
+ * @file: file being opened
+ *
+ */
+
+int v9fs_file_open(struct inode *inode, struct file *file)
+{
+	int err;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid;
+	int omode;
+	int o_append;
+
+	p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
+	v9ses = v9fs_inode2v9ses(inode);
+	if (v9fs_proto_dotl(v9ses)) {
+		omode = v9fs_open_to_dotl_flags(file->f_flags);
+		o_append = P9_DOTL_APPEND;
+	} else {
+		omode = v9fs_uflags2omode(file->f_flags,
+					v9fs_proto_dotu(v9ses));
+		o_append = P9_OAPPEND;
+	}
+	fid = file->private_data;
+	if (!fid) {
+		fid = v9fs_fid_clone(file_dentry(file));
+		if (IS_ERR(fid))
+			return PTR_ERR(fid);
+
+		if ((v9ses->cache & CACHE_WRITEBACK) && (omode & P9_OWRITE)) {
+			int writeback_omode = (omode & ~(P9_OWRITE | o_append)) | P9_ORDWR;
+
+			p9_debug(P9_DEBUG_CACHE, "write-only file with writeback enabled, try opening O_RDWR\n");
+
+			err = p9_client_open(fid, writeback_omode);
+			if (err < 0) {
+				p9_debug(P9_DEBUG_CACHE, "could not open O_RDWR, disabling caches\n");
+				err = p9_client_open(fid, omode);
+				fid->mode |= P9L_DIRECT;
+			}
+		} else {
+			err = p9_client_open(fid, omode);
+		}
+		if (err < 0) {
+			p9_fid_put(fid);
+			return err;
+		}
+		if ((file->f_flags & O_APPEND) &&
+			(!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
+			generic_file_llseek(file, 0, SEEK_END);
+
+		file->private_data = fid;
+	}
+
+#ifdef CONFIG_9P_FSCACHE
+	if (v9ses->cache & CACHE_FSCACHE)
+		fscache_use_cookie(v9fs_inode_cookie(V9FS_I(inode)),
+				   file->f_mode & FMODE_WRITE);
+#endif
+	v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
+	v9fs_open_fid_add(inode, &fid);
+	return 0;
+}
+
+/**
+ * v9fs_file_lock - lock a file (or directory)
+ * @filp: file to be locked
+ * @cmd: lock command
+ * @fl: file lock structure
+ *
+ * Bugs: this looks like a local only lock, we should extend into 9P
+ *       by using open exclusive
+ */
+
+static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
+{
+	struct inode *inode = file_inode(filp);
+
+	p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
+
+	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
+		filemap_write_and_wait(inode->i_mapping);
+		invalidate_mapping_pages(&inode->i_data, 0, -1);
+	}
+
+	return 0;
+}
+
+static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
+{
+	struct p9_flock flock;
+	struct p9_fid *fid;
+	uint8_t status = P9_LOCK_ERROR;
+	int res = 0;
+	struct v9fs_session_info *v9ses;
+
+	fid = filp->private_data;
+	BUG_ON(fid == NULL);
+
+	BUG_ON((fl->c.flc_flags & FL_POSIX) != FL_POSIX);
+
+	res = locks_lock_file_wait(filp, fl);
+	if (res < 0)
+		goto out;
+
+	/* convert posix lock to p9 tlock args */
+	memset(&flock, 0, sizeof(flock));
+	/* map the lock type */
+	switch (fl->c.flc_type) {
+	case F_RDLCK:
+		flock.type = P9_LOCK_TYPE_RDLCK;
+		break;
+	case F_WRLCK:
+		flock.type = P9_LOCK_TYPE_WRLCK;
+		break;
+	case F_UNLCK:
+		flock.type = P9_LOCK_TYPE_UNLCK;
+		break;
+	}
+	flock.start = fl->fl_start;
+	if (fl->fl_end == OFFSET_MAX)
+		flock.length = 0;
+	else
+		flock.length = fl->fl_end - fl->fl_start + 1;
+	flock.proc_id = fl->c.flc_pid;
+	flock.client_id = fid->clnt->name;
+	if (IS_SETLKW(cmd))
+		flock.flags = P9_LOCK_FLAGS_BLOCK;
+
+	v9ses = v9fs_inode2v9ses(file_inode(filp));
+
+	/*
+	 * if its a blocked request and we get P9_LOCK_BLOCKED as the status
+	 * for lock request, keep on trying
+	 */
+	for (;;) {
+		res = p9_client_lock_dotl(fid, &flock, &status);
+		if (res < 0)
+			goto out_unlock;
+
+		if (status != P9_LOCK_BLOCKED)
+			break;
+		if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
+			break;
+		if (schedule_timeout_interruptible(v9ses->session_lock_timeout)
+				!= 0)
+			break;
+		/*
+		 * p9_client_lock_dotl overwrites flock.client_id with the
+		 * server message, free and reuse the client name
+		 */
+		if (flock.client_id != fid->clnt->name) {
+			kfree(flock.client_id);
+			flock.client_id = fid->clnt->name;
+		}
+	}
+
+	/* map 9p status to VFS status */
+	switch (status) {
+	case P9_LOCK_SUCCESS:
+		res = 0;
+		break;
+	case P9_LOCK_BLOCKED:
+		res = -EAGAIN;
+		break;
+	default:
+		p9_debug(P9_DEBUG_ERROR, "unknown lock status code: %d\n", status);
+		fallthrough;
+	case P9_LOCK_ERROR:
+	case P9_LOCK_GRACE:
+		res = -ENOLCK;
+		break;
+	}
+
+out_unlock:
+	/*
+	 * incase server returned error for lock request, revert
+	 * it locally
+	 */
+	if (res < 0 && fl->c.flc_type != F_UNLCK) {
+		unsigned char type = fl->c.flc_type;
+
+		fl->c.flc_type = F_UNLCK;
+		/* Even if this fails we want to return the remote error */
+		locks_lock_file_wait(filp, fl);
+		fl->c.flc_type = type;
+	}
+	if (flock.client_id != fid->clnt->name)
+		kfree(flock.client_id);
+out:
+	return res;
+}
+
+static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
+{
+	struct p9_getlock glock;
+	struct p9_fid *fid;
+	int res = 0;
+
+	fid = filp->private_data;
+	BUG_ON(fid == NULL);
+
+	posix_test_lock(filp, fl);
+	/*
+	 * if we have a conflicting lock locally, no need to validate
+	 * with server
+	 */
+	if (fl->c.flc_type != F_UNLCK)
+		return res;
+
+	/* convert posix lock to p9 tgetlock args */
+	memset(&glock, 0, sizeof(glock));
+	glock.type  = P9_LOCK_TYPE_UNLCK;
+	glock.start = fl->fl_start;
+	if (fl->fl_end == OFFSET_MAX)
+		glock.length = 0;
+	else
+		glock.length = fl->fl_end - fl->fl_start + 1;
+	glock.proc_id = fl->c.flc_pid;
+	glock.client_id = fid->clnt->name;
+
+	res = p9_client_getlock_dotl(fid, &glock);
+	if (res < 0)
+		goto out;
+	/* map 9p lock type to os lock type */
+	switch (glock.type) {
+	case P9_LOCK_TYPE_RDLCK:
+		fl->c.flc_type = F_RDLCK;
+		break;
+	case P9_LOCK_TYPE_WRLCK:
+		fl->c.flc_type = F_WRLCK;
+		break;
+	case P9_LOCK_TYPE_UNLCK:
+		fl->c.flc_type = F_UNLCK;
+		break;
+	}
+	if (glock.type != P9_LOCK_TYPE_UNLCK) {
+		fl->fl_start = glock.start;
+		if (glock.length == 0)
+			fl->fl_end = OFFSET_MAX;
+		else
+			fl->fl_end = glock.start + glock.length - 1;
+		fl->c.flc_pid = -glock.proc_id;
+	}
+out:
+	if (glock.client_id != fid->clnt->name)
+		kfree(glock.client_id);
+	return res;
+}
+
+/**
+ * v9fs_file_lock_dotl - lock a file (or directory)
+ * @filp: file to be locked
+ * @cmd: lock command
+ * @fl: file lock structure
+ *
+ */
+
+static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
+{
+	struct inode *inode = file_inode(filp);
+	int ret = -ENOLCK;
+
+	p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
+		 filp, cmd, fl, filp);
+
+	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
+		filemap_write_and_wait(inode->i_mapping);
+		invalidate_mapping_pages(&inode->i_data, 0, -1);
+	}
+
+	if (IS_SETLK(cmd) || IS_SETLKW(cmd))
+		ret = v9fs_file_do_lock(filp, cmd, fl);
+	else if (IS_GETLK(cmd))
+		ret = v9fs_file_getlock(filp, fl);
+	else
+		ret = -EINVAL;
+	return ret;
+}
+
+/**
+ * v9fs_file_flock_dotl - lock a file
+ * @filp: file to be locked
+ * @cmd: lock command
+ * @fl: file lock structure
+ *
+ */
+
+static int v9fs_file_flock_dotl(struct file *filp, int cmd,
+	struct file_lock *fl)
+{
+	struct inode *inode = file_inode(filp);
+	int ret = -ENOLCK;
+
+	p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
+		 filp, cmd, fl, filp);
+
+	if (!(fl->c.flc_flags & FL_FLOCK))
+		goto out_err;
+
+	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
+		filemap_write_and_wait(inode->i_mapping);
+		invalidate_mapping_pages(&inode->i_data, 0, -1);
+	}
+	/* Convert flock to posix lock */
+	fl->c.flc_flags |= FL_POSIX;
+	fl->c.flc_flags ^= FL_FLOCK;
+
+	if (IS_SETLK(cmd) | IS_SETLKW(cmd))
+		ret = v9fs_file_do_lock(filp, cmd, fl);
+	else
+		ret = -EINVAL;
+out_err:
+	return ret;
+}
+
+/**
+ * v9fs_file_read_iter - read from a file
+ * @iocb: The operation parameters
+ * @to: The buffer to read into
+ *
+ */
+static ssize_t
+v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct p9_fid *fid = iocb->ki_filp->private_data;
+
+	p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
+		 fid->fid, iov_iter_count(to), iocb->ki_pos);
+
+	if (fid->mode & P9L_DIRECT)
+		return netfs_unbuffered_read_iter(iocb, to);
+
+	p9_debug(P9_DEBUG_VFS, "(cached)\n");
+	return netfs_file_read_iter(iocb, to);
+}
+
+/*
+ * v9fs_file_splice_read - splice-read from a file
+ * @in: The 9p file to read from
+ * @ppos: Where to find/update the file position
+ * @pipe: The pipe to splice into
+ * @len: The maximum amount of data to splice
+ * @flags: SPLICE_F_* flags
+ */
+static ssize_t v9fs_file_splice_read(struct file *in, loff_t *ppos,
+				     struct pipe_inode_info *pipe,
+				     size_t len, unsigned int flags)
+{
+	struct p9_fid *fid = in->private_data;
+
+	p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
+		 fid->fid, len, *ppos);
+
+	if (fid->mode & P9L_DIRECT)
+		return copy_splice_read(in, ppos, pipe, len, flags);
+	return filemap_splice_read(in, ppos, pipe, len, flags);
+}
+
+/**
+ * v9fs_file_write_iter - write to a file
+ * @iocb: The operation parameters
+ * @from: The data to write
+ *
+ */
+static ssize_t
+v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct p9_fid *fid = file->private_data;
+
+	p9_debug(P9_DEBUG_VFS, "fid %d\n", fid->fid);
+
+	if (fid->mode & (P9L_DIRECT | P9L_NOWRITECACHE))
+		return netfs_unbuffered_write_iter(iocb, from);
+
+	p9_debug(P9_DEBUG_CACHE, "(cached)\n");
+	return netfs_file_write_iter(iocb, from);
+}
+
+static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
+			   int datasync)
+{
+	struct p9_fid *fid;
+	struct inode *inode = filp->f_mapping->host;
+	struct p9_wstat wstat;
+	int retval;
+
+	retval = file_write_and_wait_range(filp, start, end);
+	if (retval)
+		return retval;
+
+	inode_lock(inode);
+	p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
+
+	fid = filp->private_data;
+	v9fs_blank_wstat(&wstat);
+
+	retval = p9_client_wstat(fid, &wstat);
+	inode_unlock(inode);
+
+	return retval;
+}
+
+int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
+			 int datasync)
+{
+	struct p9_fid *fid;
+	struct inode *inode = filp->f_mapping->host;
+	int retval;
+
+	retval = file_write_and_wait_range(filp, start, end);
+	if (retval)
+		return retval;
+
+	inode_lock(inode);
+	p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
+
+	fid = filp->private_data;
+
+	retval = p9_client_fsync(fid, datasync);
+	inode_unlock(inode);
+
+	return retval;
+}
+
+static int
+v9fs_file_mmap_prepare(struct vm_area_desc *desc)
+{
+	int retval;
+	struct file *filp = desc->file;
+	struct inode *inode = file_inode(filp);
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
+
+	p9_debug(P9_DEBUG_MMAP, "filp :%p\n", filp);
+
+	if (!(v9ses->cache & CACHE_WRITEBACK)) {
+		p9_debug(P9_DEBUG_CACHE, "(read-only mmap mode)");
+		return generic_file_readonly_mmap_prepare(desc);
+	}
+
+	retval = generic_file_mmap_prepare(desc);
+	if (!retval)
+		desc->vm_ops = &v9fs_mmap_file_vm_ops;
+
+	return retval;
+}
+
+static vm_fault_t
+v9fs_vm_page_mkwrite(struct vm_fault *vmf)
+{
+	return netfs_page_mkwrite(vmf, NULL);
+}
+
+static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
+{
+	if (!(vma->vm_flags & VM_SHARED))
+		return;
+
+	p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
+
+	filemap_fdatawrite_range(file_inode(vma->vm_file)->i_mapping,
+			(loff_t)vma->vm_pgoff * PAGE_SIZE,
+			(loff_t)vma->vm_pgoff * PAGE_SIZE +
+				(vma->vm_end - vma->vm_start - 1));
+}
+
+static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
+	.close = v9fs_mmap_vm_close,
+	.fault = filemap_fault,
+	.map_pages = filemap_map_pages,
+	.page_mkwrite = v9fs_vm_page_mkwrite,
+};
+
+const struct file_operations v9fs_file_operations = {
+	.llseek = generic_file_llseek,
+	.read_iter = v9fs_file_read_iter,
+	.write_iter = v9fs_file_write_iter,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock,
+	.mmap_prepare = generic_file_readonly_mmap_prepare,
+	.splice_read = v9fs_file_splice_read,
+	.splice_write = iter_file_splice_write,
+	.fsync = v9fs_file_fsync,
+};
+
+const struct file_operations v9fs_file_operations_dotl = {
+	.llseek = generic_file_llseek,
+	.read_iter = v9fs_file_read_iter,
+	.write_iter = v9fs_file_write_iter,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock_dotl,
+	.flock = v9fs_file_flock_dotl,
+	.mmap_prepare = v9fs_file_mmap_prepare,
+	.splice_read = v9fs_file_splice_read,
+	.splice_write = iter_file_splice_write,
+	.fsync = v9fs_file_fsync_dotl,
+};