1// SPDX-License-Identifier: GPL-2.0
2/*
3 * (C) 2001 Clemson University and The University of Chicago
4 * Copyright 2018 Omnibond Systems, L.L.C.
5 *
6 * See COPYING in top-level directory.
7 */
8
9/*
10 *  Linux VFS file operations.
11 */
12
13#include "protocol.h"
14#include "orangefs-kernel.h"
15#include "orangefs-bufmap.h"
16#include <linux/fs.h>
17#include <linux/filelock.h>
18#include <linux/pagemap.h>
19
20static int flush_racache(struct inode *inode)
21{
22	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
23	struct orangefs_kernel_op_s *new_op;
24	int ret;
25
26	gossip_debug(GOSSIP_UTILS_DEBUG,
27	    "%s: %pU: Handle is %pU | fs_id %d\n", __func__,
28	    get_khandle_from_ino(inode), &orangefs_inode->refn.khandle,
29	    orangefs_inode->refn.fs_id);
30
31	new_op = op_alloc(ORANGEFS_VFS_OP_RA_FLUSH);
32	if (!new_op)
33		return -ENOMEM;
34	new_op->upcall.req.ra_cache_flush.refn = orangefs_inode->refn;
35
36	ret = service_operation(new_op, "orangefs_flush_racache",
37	    get_interruptible_flag(inode));
38
39	gossip_debug(GOSSIP_UTILS_DEBUG, "%s: got return value of %d\n",
40	    __func__, ret);
41
42	op_release(new_op);
43	return ret;
44}
45
46/*
47 * Post and wait for the I/O upcall to finish
48 */
49ssize_t wait_for_direct_io(enum ORANGEFS_io_type type, struct inode *inode,
50	loff_t *offset, struct iov_iter *iter, size_t total_size,
51	loff_t readahead_size, struct orangefs_write_range *wr,
52	int *index_return, struct file *file)
53{
54	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
55	struct orangefs_khandle *handle = &orangefs_inode->refn.khandle;
56	struct orangefs_kernel_op_s *new_op = NULL;
57	int buffer_index;
58	ssize_t ret;
59	size_t copy_amount;
60	int open_for_read;
61	int open_for_write;
62
63	new_op = op_alloc(ORANGEFS_VFS_OP_FILE_IO);
64	if (!new_op)
65		return -ENOMEM;
66
67	/* synchronous I/O */
68	new_op->upcall.req.io.readahead_size = readahead_size;
69	new_op->upcall.req.io.io_type = type;
70	new_op->upcall.req.io.refn = orangefs_inode->refn;
71
72populate_shared_memory:
73	/* get a shared buffer index */
74	buffer_index = orangefs_bufmap_get();
75	if (buffer_index < 0) {
76		ret = buffer_index;
77		gossip_debug(GOSSIP_FILE_DEBUG,
78			     "%s: orangefs_bufmap_get failure (%zd)\n",
79			     __func__, ret);
80		goto out;
81	}
82	gossip_debug(GOSSIP_FILE_DEBUG,
83		     "%s(%pU): GET op %p -> buffer_index %d\n",
84		     __func__,
85		     handle,
86		     new_op,
87		     buffer_index);
88
89	new_op->uses_shared_memory = 1;
90	new_op->upcall.req.io.buf_index = buffer_index;
91	new_op->upcall.req.io.count = total_size;
92	new_op->upcall.req.io.offset = *offset;
93	if (type == ORANGEFS_IO_WRITE && wr) {
94		new_op->upcall.uid = from_kuid(&init_user_ns, wr->uid);
95		new_op->upcall.gid = from_kgid(&init_user_ns, wr->gid);
96	}
97	/*
98	 * Orangefs has no open, and orangefs checks file permissions
99	 * on each file access. Posix requires that file permissions
100	 * be checked on open and nowhere else. Orangefs-through-the-kernel
101	 * needs to seem posix compliant.
102	 *
103	 * The VFS opens files, even if the filesystem provides no
104	 * method. We can see if a file was successfully opened for
105	 * read and or for write by looking at file->f_mode.
106	 *
107	 * When writes are flowing from the page cache, file is no
108	 * longer available. We can trust the VFS to have checked
109	 * file->f_mode before writing to the page cache.
110	 *
111	 * The mode of a file might change between when it is opened
112	 * and IO commences, or it might be created with an arbitrary mode.
113	 *
114	 * We'll make sure we don't hit EACCES during the IO stage by
115	 * using UID 0. Some of the time we have access without changing
116	 * to UID 0 - how to check?
117	 */
118	if (file) {
119		open_for_write = file->f_mode & FMODE_WRITE;
120		open_for_read = file->f_mode & FMODE_READ;
121	} else {
122		open_for_write = 1;
123		open_for_read = 0; /* not relevant? */
124	}
125	if ((type == ORANGEFS_IO_WRITE) && open_for_write)
126		new_op->upcall.uid = 0;
127	if ((type == ORANGEFS_IO_READ) && open_for_read)
128		new_op->upcall.uid = 0;
129
130	gossip_debug(GOSSIP_FILE_DEBUG,
131		     "%s(%pU): offset: %llu total_size: %zd\n",
132		     __func__,
133		     handle,
134		     llu(*offset),
135		     total_size);
136	/*
137	 * Stage 1: copy the buffers into client-core's address space
138	 */
139	if (type == ORANGEFS_IO_WRITE && total_size) {
140		ret = orangefs_bufmap_copy_from_iovec(iter, buffer_index,
141		    total_size);
142		if (ret < 0) {
143			gossip_err("%s: Failed to copy-in buffers. Please make sure that the pvfs2-client is running. %ld\n",
144			    __func__, (long)ret);
145			goto out;
146		}
147	}
148
149	gossip_debug(GOSSIP_FILE_DEBUG,
150		     "%s(%pU): Calling post_io_request with tag (%llu)\n",
151		     __func__,
152		     handle,
153		     llu(new_op->tag));
154
155	/* Stage 2: Service the I/O operation */
156	ret = service_operation(new_op,
157				type == ORANGEFS_IO_WRITE ?
158					"file_write" :
159					"file_read",
160				get_interruptible_flag(inode));
161
162	/*
163	 * If service_operation() returns -EAGAIN #and# the operation was
164	 * purged from orangefs_request_list or htable_ops_in_progress, then
165	 * we know that the client was restarted, causing the shared memory
166	 * area to be wiped clean.  To restart a  write operation in this
167	 * case, we must re-copy the data from the user's iovec to a NEW
168	 * shared memory location. To restart a read operation, we must get
169	 * a new shared memory location.
170	 */
171	if (ret == -EAGAIN && op_state_purged(new_op)) {
172		orangefs_bufmap_put(buffer_index);
173		if (type == ORANGEFS_IO_WRITE)
174			iov_iter_revert(iter, total_size);
175		gossip_debug(GOSSIP_FILE_DEBUG,
176			     "%s:going to repopulate_shared_memory.\n",
177			     __func__);
178		goto populate_shared_memory;
179	}
180
181	if (ret < 0) {
182		if (ret == -EINTR) {
183			/*
184			 * We can't return EINTR if any data was written,
185			 * it's not POSIX. It is minimally acceptable
186			 * to give a partial write, the way NFS does.
187			 *
188			 * It would be optimal to return all or nothing,
189			 * but if a userspace write is bigger than
190			 * an IO buffer, and the interrupt occurs
191			 * between buffer writes, that would not be
192			 * possible.
193			 */
194			switch (new_op->op_state - OP_VFS_STATE_GIVEN_UP) {
195			/*
196			 * If the op was waiting when the interrupt
197			 * occurred, then the client-core did not
198			 * trigger the write.
199			 */
200			case OP_VFS_STATE_WAITING:
201				if (*offset == 0)
202					ret = -EINTR;
203				else
204					ret = 0;
205				break;
206			/*
207			 * If the op was in progress when the interrupt
208			 * occurred, then the client-core was able to
209			 * trigger the write.
210			 */
211			case OP_VFS_STATE_INPROGR:
212				if (type == ORANGEFS_IO_READ)
213					ret = -EINTR;
214				else
215					ret = total_size;
216				break;
217			default:
218				gossip_err("%s: unexpected op state :%d:.\n",
219					   __func__,
220					   new_op->op_state);
221				ret = 0;
222				break;
223			}
224			gossip_debug(GOSSIP_FILE_DEBUG,
225				     "%s: got EINTR, state:%d: %p\n",
226				     __func__,
227				     new_op->op_state,
228				     new_op);
229		} else {
230			gossip_err("%s: error in %s handle %pU, returning %zd\n",
231				__func__,
232				type == ORANGEFS_IO_READ ?
233					"read from" : "write to",
234				handle, ret);
235		}
236		if (orangefs_cancel_op_in_progress(new_op))
237			return ret;
238
239		goto out;
240	}
241
242	/*
243	 * Stage 3: Post copy buffers from client-core's address space
244	 */
245	if (type == ORANGEFS_IO_READ && new_op->downcall.resp.io.amt_complete) {
246		/*
247		 * NOTE: the iovector can either contain addresses which
248		 *       can futher be kernel-space or user-space addresses.
249		 *       or it can pointers to struct page's
250		 */
251
252		copy_amount = new_op->downcall.resp.io.amt_complete;
253
254		ret = orangefs_bufmap_copy_to_iovec(iter, buffer_index,
255			copy_amount);
256		if (ret < 0) {
257			gossip_err("%s: Failed to copy-out buffers. Please make sure that the pvfs2-client is running (%ld)\n",
258			    __func__, (long)ret);
259			goto out;
260		}
261	}
262	gossip_debug(GOSSIP_FILE_DEBUG,
263	    "%s(%pU): Amount %s, returned by the sys-io call:%d\n",
264	    __func__,
265	    handle,
266	    type == ORANGEFS_IO_READ ?  "read" : "written",
267	    (int)new_op->downcall.resp.io.amt_complete);
268
269	ret = new_op->downcall.resp.io.amt_complete;
270
271out:
272	if (buffer_index >= 0) {
273		orangefs_bufmap_put(buffer_index);
274		gossip_debug(GOSSIP_FILE_DEBUG,
275			"%s(%pU): PUT buffer_index %d\n",
276			__func__, handle, buffer_index);
277	}
278	op_release(new_op);
279	return ret;
280}
281
282int orangefs_revalidate_mapping(struct inode *inode)
283{
284	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
285	struct address_space *mapping = inode->i_mapping;
286	unsigned long *bitlock = &orangefs_inode->bitlock;
287	int ret;
288
289	while (1) {
290		ret = wait_on_bit(bitlock, 1, TASK_KILLABLE);
291		if (ret)
292			return ret;
293		spin_lock(&inode->i_lock);
294		if (test_bit(1, bitlock)) {
295			spin_unlock(&inode->i_lock);
296			continue;
297		}
298		if (!time_before(jiffies, orangefs_inode->mapping_time))
299			break;
300		spin_unlock(&inode->i_lock);
301		return 0;
302	}
303
304	set_bit(1, bitlock);
305	smp_wmb();
306	spin_unlock(&inode->i_lock);
307
308	unmap_mapping_range(mapping, 0, 0, 0);
309	ret = filemap_write_and_wait(mapping);
310	if (!ret)
311		ret = invalidate_inode_pages2(mapping);
312
313	orangefs_inode->mapping_time = jiffies +
314	    orangefs_cache_timeout_msecs*HZ/1000;
315
316	clear_bit(1, bitlock);
317	smp_mb__after_atomic();
318	wake_up_bit(bitlock, 1);
319
320	return ret;
321}
322
323static ssize_t orangefs_file_read_iter(struct kiocb *iocb,
324    struct iov_iter *iter)
325{
326	int ret;
327	orangefs_stats.reads++;
328
329	down_read(&file_inode(iocb->ki_filp)->i_rwsem);
330	ret = orangefs_revalidate_mapping(file_inode(iocb->ki_filp));
331	if (ret)
332		goto out;
333
334	ret = generic_file_read_iter(iocb, iter);
335out:
336	up_read(&file_inode(iocb->ki_filp)->i_rwsem);
337	return ret;
338}
339
340static ssize_t orangefs_file_splice_read(struct file *in, loff_t *ppos,
341					 struct pipe_inode_info *pipe,
342					 size_t len, unsigned int flags)
343{
344	struct inode *inode = file_inode(in);
345	ssize_t ret;
346
347	orangefs_stats.reads++;
348
349	down_read(&inode->i_rwsem);
350	ret = orangefs_revalidate_mapping(inode);
351	if (ret)
352		goto out;
353
354	ret = filemap_splice_read(in, ppos, pipe, len, flags);
355out:
356	up_read(&inode->i_rwsem);
357	return ret;
358}
359
360static ssize_t orangefs_file_write_iter(struct kiocb *iocb,
361    struct iov_iter *iter)
362{
363	int ret;
364	orangefs_stats.writes++;
365
366	if (iocb->ki_pos > i_size_read(file_inode(iocb->ki_filp))) {
367		ret = orangefs_revalidate_mapping(file_inode(iocb->ki_filp));
368		if (ret)
369			return ret;
370	}
371
372	ret = generic_file_write_iter(iocb, iter);
373	return ret;
374}
375
376static vm_fault_t orangefs_fault(struct vm_fault *vmf)
377{
378	struct file *file = vmf->vma->vm_file;
379	int ret;
380	ret = orangefs_inode_getattr(file->f_mapping->host,
381	    ORANGEFS_GETATTR_SIZE);
382	if (ret == -ESTALE)
383		ret = -EIO;
384	if (ret) {
385		gossip_err("%s: orangefs_inode_getattr failed, "
386		    "ret:%d:.\n", __func__, ret);
387		return VM_FAULT_SIGBUS;
388	}
389	return filemap_fault(vmf);
390}
391
392static const struct vm_operations_struct orangefs_file_vm_ops = {
393	.fault = orangefs_fault,
394	.map_pages = filemap_map_pages,
395	.page_mkwrite = orangefs_page_mkwrite,
396};
397
398/*
399 * Memory map a region of a file.
400 */
401static int orangefs_file_mmap(struct file *file, struct vm_area_struct *vma)
402{
403	int ret;
404
405	ret = orangefs_revalidate_mapping(file_inode(file));
406	if (ret)
407		return ret;
408
409	gossip_debug(GOSSIP_FILE_DEBUG,
410		     "orangefs_file_mmap: called on %pD\n", file);
411
412	/* set the sequential readahead hint */
413	vm_flags_mod(vma, VM_SEQ_READ, VM_RAND_READ);
414
415	file_accessed(file);
416	vma->vm_ops = &orangefs_file_vm_ops;
417	return 0;
418}
419
420#define mapping_nrpages(idata) ((idata)->nrpages)
421
422/*
423 * Called to notify the module that there are no more references to
424 * this file (i.e. no processes have it open).
425 *
426 * \note Not called when each file is closed.
427 */
428static int orangefs_file_release(struct inode *inode, struct file *file)
429{
430	gossip_debug(GOSSIP_FILE_DEBUG,
431		     "orangefs_file_release: called on %pD\n",
432		     file);
433
434	/*
435	 * remove all associated inode pages from the page cache and
436	 * readahead cache (if any); this forces an expensive refresh of
437	 * data for the next caller of mmap (or 'get_block' accesses)
438	 */
439	if (mapping_nrpages(file->f_mapping)) {
440		if (orangefs_features & ORANGEFS_FEATURE_READAHEAD) {
441			gossip_debug(GOSSIP_INODE_DEBUG,
442			    "calling flush_racache on %pU\n",
443			    get_khandle_from_ino(inode));
444			flush_racache(inode);
445			gossip_debug(GOSSIP_INODE_DEBUG,
446			    "flush_racache finished\n");
447		}
448
449	}
450	return 0;
451}
452
453/*
454 * Push all data for a specific file onto permanent storage.
455 */
456static int orangefs_fsync(struct file *file,
457		       loff_t start,
458		       loff_t end,
459		       int datasync)
460{
461	int ret;
462	struct orangefs_inode_s *orangefs_inode =
463		ORANGEFS_I(file_inode(file));
464	struct orangefs_kernel_op_s *new_op = NULL;
465
466	ret = filemap_write_and_wait_range(file_inode(file)->i_mapping,
467	    start, end);
468	if (ret < 0)
469		return ret;
470
471	new_op = op_alloc(ORANGEFS_VFS_OP_FSYNC);
472	if (!new_op)
473		return -ENOMEM;
474	new_op->upcall.req.fsync.refn = orangefs_inode->refn;
475
476	ret = service_operation(new_op,
477			"orangefs_fsync",
478			get_interruptible_flag(file_inode(file)));
479
480	gossip_debug(GOSSIP_FILE_DEBUG,
481		     "orangefs_fsync got return value of %d\n",
482		     ret);
483
484	op_release(new_op);
485	return ret;
486}
487
488/*
489 * Change the file pointer position for an instance of an open file.
490 *
491 * \note If .llseek is overriden, we must acquire lock as described in
492 *       Documentation/filesystems/locking.rst.
493 *
494 * Future upgrade could support SEEK_DATA and SEEK_HOLE but would
495 * require much changes to the FS
496 */
497static loff_t orangefs_file_llseek(struct file *file, loff_t offset, int origin)
498{
499	int ret = -EINVAL;
500	struct inode *inode = file_inode(file);
501
502	if (origin == SEEK_END) {
503		/*
504		 * revalidate the inode's file size.
505		 * NOTE: We are only interested in file size here,
506		 * so we set mask accordingly.
507		 */
508		ret = orangefs_inode_getattr(file->f_mapping->host,
509		    ORANGEFS_GETATTR_SIZE);
510		if (ret == -ESTALE)
511			ret = -EIO;
512		if (ret) {
513			gossip_debug(GOSSIP_FILE_DEBUG,
514				     "%s:%s:%d calling make bad inode\n",
515				     __FILE__,
516				     __func__,
517				     __LINE__);
518			return ret;
519		}
520	}
521
522	gossip_debug(GOSSIP_FILE_DEBUG,
523		     "orangefs_file_llseek: offset is %ld | origin is %d"
524		     " | inode size is %lu\n",
525		     (long)offset,
526		     origin,
527		     (unsigned long)i_size_read(inode));
528
529	return generic_file_llseek(file, offset, origin);
530}
531
532/*
533 * Support local locks (locks that only this kernel knows about)
534 * if Orangefs was mounted -o local_lock.
535 */
536static int orangefs_lock(struct file *filp, int cmd, struct file_lock *fl)
537{
538	int rc = -EINVAL;
539
540	if (ORANGEFS_SB(file_inode(filp)->i_sb)->flags & ORANGEFS_OPT_LOCAL_LOCK) {
541		if (cmd == F_GETLK) {
542			rc = 0;
543			posix_test_lock(filp, fl);
544		} else {
545			rc = posix_lock_file(filp, fl, NULL);
546		}
547	}
548
549	return rc;
550}
551
552static int orangefs_flush(struct file *file, fl_owner_t id)
553{
554	/*
555	 * This is vfs_fsync_range(file, 0, LLONG_MAX, 0) without the
556	 * service_operation in orangefs_fsync.
557	 *
558	 * Do not send fsync to OrangeFS server on a close.  Do send fsync
559	 * on an explicit fsync call.  This duplicates historical OrangeFS
560	 * behavior.
561	 */
562	int r;
563
564	r = filemap_write_and_wait_range(file->f_mapping, 0, LLONG_MAX);
565	if (r > 0)
566		return 0;
567	else
568		return r;
569}
570
571/** ORANGEFS implementation of VFS file operations */
572const struct file_operations orangefs_file_operations = {
573	.llseek		= orangefs_file_llseek,
574	.read_iter	= orangefs_file_read_iter,
575	.write_iter	= orangefs_file_write_iter,
576	.lock		= orangefs_lock,
577	.mmap		= orangefs_file_mmap,
578	.open		= generic_file_open,
579	.splice_read    = orangefs_file_splice_read,
580	.splice_write   = iter_file_splice_write,
581	.flush		= orangefs_flush,
582	.release	= orangefs_file_release,
583	.fsync		= orangefs_fsync,
584};
585