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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * This file contians vfs file ops for 9P2000.4 *5 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>6 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>7 */8 9#include <linux/module.h>10#include <linux/errno.h>11#include <linux/fs.h>12#include <linux/filelock.h>13#include <linux/sched.h>14#include <linux/file.h>15#include <linux/stat.h>16#include <linux/string.h>17#include <linux/list.h>18#include <linux/pagemap.h>19#include <linux/utsname.h>20#include <linux/uaccess.h>21#include <linux/uio.h>22#include <linux/slab.h>23#include <net/9p/9p.h>24#include <net/9p/client.h>25 26#include "v9fs.h"27#include "v9fs_vfs.h"28#include "fid.h"29#include "cache.h"30 31static const struct vm_operations_struct v9fs_mmap_file_vm_ops;32 33/**34 * v9fs_file_open - open a file (or directory)35 * @inode: inode to be opened36 * @file: file being opened37 *38 */39 40int v9fs_file_open(struct inode *inode, struct file *file)41{42 int err;43 struct v9fs_session_info *v9ses;44 struct p9_fid *fid;45 int omode;46 47 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);48 v9ses = v9fs_inode2v9ses(inode);49 if (v9fs_proto_dotl(v9ses))50 omode = v9fs_open_to_dotl_flags(file->f_flags);51 else52 omode = v9fs_uflags2omode(file->f_flags,53 v9fs_proto_dotu(v9ses));54 fid = file->private_data;55 if (!fid) {56 fid = v9fs_fid_clone(file_dentry(file));57 if (IS_ERR(fid))58 return PTR_ERR(fid);59 60 if ((v9ses->cache & CACHE_WRITEBACK) && (omode & P9_OWRITE)) {61 int writeback_omode = (omode & ~P9_OWRITE) | P9_ORDWR;62 63 p9_debug(P9_DEBUG_CACHE, "write-only file with writeback enabled, try opening O_RDWR\n");64 err = p9_client_open(fid, writeback_omode);65 if (err < 0) {66 p9_debug(P9_DEBUG_CACHE, "could not open O_RDWR, disabling caches\n");67 err = p9_client_open(fid, omode);68 fid->mode |= P9L_DIRECT;69 }70 } else {71 err = p9_client_open(fid, omode);72 }73 if (err < 0) {74 p9_fid_put(fid);75 return err;76 }77 if ((file->f_flags & O_APPEND) &&78 (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))79 generic_file_llseek(file, 0, SEEK_END);80 81 file->private_data = fid;82 }83 84#ifdef CONFIG_9P_FSCACHE85 if (v9ses->cache & CACHE_FSCACHE)86 fscache_use_cookie(v9fs_inode_cookie(V9FS_I(inode)),87 file->f_mode & FMODE_WRITE);88#endif89 v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);90 v9fs_open_fid_add(inode, &fid);91 return 0;92}93 94/**95 * v9fs_file_lock - lock a file (or directory)96 * @filp: file to be locked97 * @cmd: lock command98 * @fl: file lock structure99 *100 * Bugs: this looks like a local only lock, we should extend into 9P101 * by using open exclusive102 */103 104static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)105{106 struct inode *inode = file_inode(filp);107 108 p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);109 110 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {111 filemap_write_and_wait(inode->i_mapping);112 invalidate_mapping_pages(&inode->i_data, 0, -1);113 }114 115 return 0;116}117 118static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)119{120 struct p9_flock flock;121 struct p9_fid *fid;122 uint8_t status = P9_LOCK_ERROR;123 int res = 0;124 struct v9fs_session_info *v9ses;125 126 fid = filp->private_data;127 BUG_ON(fid == NULL);128 129 BUG_ON((fl->c.flc_flags & FL_POSIX) != FL_POSIX);130 131 res = locks_lock_file_wait(filp, fl);132 if (res < 0)133 goto out;134 135 /* convert posix lock to p9 tlock args */136 memset(&flock, 0, sizeof(flock));137 /* map the lock type */138 switch (fl->c.flc_type) {139 case F_RDLCK:140 flock.type = P9_LOCK_TYPE_RDLCK;141 break;142 case F_WRLCK:143 flock.type = P9_LOCK_TYPE_WRLCK;144 break;145 case F_UNLCK:146 flock.type = P9_LOCK_TYPE_UNLCK;147 break;148 }149 flock.start = fl->fl_start;150 if (fl->fl_end == OFFSET_MAX)151 flock.length = 0;152 else153 flock.length = fl->fl_end - fl->fl_start + 1;154 flock.proc_id = fl->c.flc_pid;155 flock.client_id = fid->clnt->name;156 if (IS_SETLKW(cmd))157 flock.flags = P9_LOCK_FLAGS_BLOCK;158 159 v9ses = v9fs_inode2v9ses(file_inode(filp));160 161 /*162 * if its a blocked request and we get P9_LOCK_BLOCKED as the status163 * for lock request, keep on trying164 */165 for (;;) {166 res = p9_client_lock_dotl(fid, &flock, &status);167 if (res < 0)168 goto out_unlock;169 170 if (status != P9_LOCK_BLOCKED)171 break;172 if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))173 break;174 if (schedule_timeout_interruptible(v9ses->session_lock_timeout)175 != 0)176 break;177 /*178 * p9_client_lock_dotl overwrites flock.client_id with the179 * server message, free and reuse the client name180 */181 if (flock.client_id != fid->clnt->name) {182 kfree(flock.client_id);183 flock.client_id = fid->clnt->name;184 }185 }186 187 /* map 9p status to VFS status */188 switch (status) {189 case P9_LOCK_SUCCESS:190 res = 0;191 break;192 case P9_LOCK_BLOCKED:193 res = -EAGAIN;194 break;195 default:196 WARN_ONCE(1, "unknown lock status code: %d\n", status);197 fallthrough;198 case P9_LOCK_ERROR:199 case P9_LOCK_GRACE:200 res = -ENOLCK;201 break;202 }203 204out_unlock:205 /*206 * incase server returned error for lock request, revert207 * it locally208 */209 if (res < 0 && fl->c.flc_type != F_UNLCK) {210 unsigned char type = fl->c.flc_type;211 212 fl->c.flc_type = F_UNLCK;213 /* Even if this fails we want to return the remote error */214 locks_lock_file_wait(filp, fl);215 fl->c.flc_type = type;216 }217 if (flock.client_id != fid->clnt->name)218 kfree(flock.client_id);219out:220 return res;221}222 223static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)224{225 struct p9_getlock glock;226 struct p9_fid *fid;227 int res = 0;228 229 fid = filp->private_data;230 BUG_ON(fid == NULL);231 232 posix_test_lock(filp, fl);233 /*234 * if we have a conflicting lock locally, no need to validate235 * with server236 */237 if (fl->c.flc_type != F_UNLCK)238 return res;239 240 /* convert posix lock to p9 tgetlock args */241 memset(&glock, 0, sizeof(glock));242 glock.type = P9_LOCK_TYPE_UNLCK;243 glock.start = fl->fl_start;244 if (fl->fl_end == OFFSET_MAX)245 glock.length = 0;246 else247 glock.length = fl->fl_end - fl->fl_start + 1;248 glock.proc_id = fl->c.flc_pid;249 glock.client_id = fid->clnt->name;250 251 res = p9_client_getlock_dotl(fid, &glock);252 if (res < 0)253 goto out;254 /* map 9p lock type to os lock type */255 switch (glock.type) {256 case P9_LOCK_TYPE_RDLCK:257 fl->c.flc_type = F_RDLCK;258 break;259 case P9_LOCK_TYPE_WRLCK:260 fl->c.flc_type = F_WRLCK;261 break;262 case P9_LOCK_TYPE_UNLCK:263 fl->c.flc_type = F_UNLCK;264 break;265 }266 if (glock.type != P9_LOCK_TYPE_UNLCK) {267 fl->fl_start = glock.start;268 if (glock.length == 0)269 fl->fl_end = OFFSET_MAX;270 else271 fl->fl_end = glock.start + glock.length - 1;272 fl->c.flc_pid = -glock.proc_id;273 }274out:275 if (glock.client_id != fid->clnt->name)276 kfree(glock.client_id);277 return res;278}279 280/**281 * v9fs_file_lock_dotl - lock a file (or directory)282 * @filp: file to be locked283 * @cmd: lock command284 * @fl: file lock structure285 *286 */287 288static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)289{290 struct inode *inode = file_inode(filp);291 int ret = -ENOLCK;292 293 p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",294 filp, cmd, fl, filp);295 296 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {297 filemap_write_and_wait(inode->i_mapping);298 invalidate_mapping_pages(&inode->i_data, 0, -1);299 }300 301 if (IS_SETLK(cmd) || IS_SETLKW(cmd))302 ret = v9fs_file_do_lock(filp, cmd, fl);303 else if (IS_GETLK(cmd))304 ret = v9fs_file_getlock(filp, fl);305 else306 ret = -EINVAL;307 return ret;308}309 310/**311 * v9fs_file_flock_dotl - lock a file312 * @filp: file to be locked313 * @cmd: lock command314 * @fl: file lock structure315 *316 */317 318static int v9fs_file_flock_dotl(struct file *filp, int cmd,319 struct file_lock *fl)320{321 struct inode *inode = file_inode(filp);322 int ret = -ENOLCK;323 324 p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",325 filp, cmd, fl, filp);326 327 if (!(fl->c.flc_flags & FL_FLOCK))328 goto out_err;329 330 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {331 filemap_write_and_wait(inode->i_mapping);332 invalidate_mapping_pages(&inode->i_data, 0, -1);333 }334 /* Convert flock to posix lock */335 fl->c.flc_flags |= FL_POSIX;336 fl->c.flc_flags ^= FL_FLOCK;337 338 if (IS_SETLK(cmd) | IS_SETLKW(cmd))339 ret = v9fs_file_do_lock(filp, cmd, fl);340 else341 ret = -EINVAL;342out_err:343 return ret;344}345 346/**347 * v9fs_file_read_iter - read from a file348 * @iocb: The operation parameters349 * @to: The buffer to read into350 *351 */352static ssize_t353v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)354{355 struct p9_fid *fid = iocb->ki_filp->private_data;356 357 p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",358 fid->fid, iov_iter_count(to), iocb->ki_pos);359 360 if (fid->mode & P9L_DIRECT)361 return netfs_unbuffered_read_iter(iocb, to);362 363 p9_debug(P9_DEBUG_VFS, "(cached)\n");364 return netfs_file_read_iter(iocb, to);365}366 367/*368 * v9fs_file_splice_read - splice-read from a file369 * @in: The 9p file to read from370 * @ppos: Where to find/update the file position371 * @pipe: The pipe to splice into372 * @len: The maximum amount of data to splice373 * @flags: SPLICE_F_* flags374 */375static ssize_t v9fs_file_splice_read(struct file *in, loff_t *ppos,376 struct pipe_inode_info *pipe,377 size_t len, unsigned int flags)378{379 struct p9_fid *fid = in->private_data;380 381 p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",382 fid->fid, len, *ppos);383 384 if (fid->mode & P9L_DIRECT)385 return copy_splice_read(in, ppos, pipe, len, flags);386 return filemap_splice_read(in, ppos, pipe, len, flags);387}388 389/**390 * v9fs_file_write_iter - write to a file391 * @iocb: The operation parameters392 * @from: The data to write393 *394 */395static ssize_t396v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)397{398 struct file *file = iocb->ki_filp;399 struct p9_fid *fid = file->private_data;400 401 p9_debug(P9_DEBUG_VFS, "fid %d\n", fid->fid);402 403 if (fid->mode & (P9L_DIRECT | P9L_NOWRITECACHE))404 return netfs_unbuffered_write_iter(iocb, from);405 406 p9_debug(P9_DEBUG_CACHE, "(cached)\n");407 return netfs_file_write_iter(iocb, from);408}409 410static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,411 int datasync)412{413 struct p9_fid *fid;414 struct inode *inode = filp->f_mapping->host;415 struct p9_wstat wstat;416 int retval;417 418 retval = file_write_and_wait_range(filp, start, end);419 if (retval)420 return retval;421 422 inode_lock(inode);423 p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);424 425 fid = filp->private_data;426 v9fs_blank_wstat(&wstat);427 428 retval = p9_client_wstat(fid, &wstat);429 inode_unlock(inode);430 431 return retval;432}433 434int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,435 int datasync)436{437 struct p9_fid *fid;438 struct inode *inode = filp->f_mapping->host;439 int retval;440 441 retval = file_write_and_wait_range(filp, start, end);442 if (retval)443 return retval;444 445 inode_lock(inode);446 p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);447 448 fid = filp->private_data;449 450 retval = p9_client_fsync(fid, datasync);451 inode_unlock(inode);452 453 return retval;454}455 456static int457v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)458{459 int retval;460 struct inode *inode = file_inode(filp);461 struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);462 463 p9_debug(P9_DEBUG_MMAP, "filp :%p\n", filp);464 465 if (!(v9ses->cache & CACHE_WRITEBACK)) {466 p9_debug(P9_DEBUG_CACHE, "(read-only mmap mode)");467 return generic_file_readonly_mmap(filp, vma);468 }469 470 retval = generic_file_mmap(filp, vma);471 if (!retval)472 vma->vm_ops = &v9fs_mmap_file_vm_ops;473 474 return retval;475}476 477static vm_fault_t478v9fs_vm_page_mkwrite(struct vm_fault *vmf)479{480 return netfs_page_mkwrite(vmf, NULL);481}482 483static void v9fs_mmap_vm_close(struct vm_area_struct *vma)484{485 struct inode *inode;486 487 struct writeback_control wbc = {488 .nr_to_write = LONG_MAX,489 .sync_mode = WB_SYNC_ALL,490 .range_start = (loff_t)vma->vm_pgoff * PAGE_SIZE,491 /* absolute end, byte at end included */492 .range_end = (loff_t)vma->vm_pgoff * PAGE_SIZE +493 (vma->vm_end - vma->vm_start - 1),494 };495 496 if (!(vma->vm_flags & VM_SHARED))497 return;498 499 p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);500 501 inode = file_inode(vma->vm_file);502 filemap_fdatawrite_wbc(inode->i_mapping, &wbc);503}504 505static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {506 .close = v9fs_mmap_vm_close,507 .fault = filemap_fault,508 .map_pages = filemap_map_pages,509 .page_mkwrite = v9fs_vm_page_mkwrite,510};511 512const struct file_operations v9fs_file_operations = {513 .llseek = generic_file_llseek,514 .read_iter = v9fs_file_read_iter,515 .write_iter = v9fs_file_write_iter,516 .open = v9fs_file_open,517 .release = v9fs_dir_release,518 .lock = v9fs_file_lock,519 .mmap = generic_file_readonly_mmap,520 .splice_read = v9fs_file_splice_read,521 .splice_write = iter_file_splice_write,522 .fsync = v9fs_file_fsync,523 .setlease = simple_nosetlease,524};525 526const struct file_operations v9fs_file_operations_dotl = {527 .llseek = generic_file_llseek,528 .read_iter = v9fs_file_read_iter,529 .write_iter = v9fs_file_write_iter,530 .open = v9fs_file_open,531 .release = v9fs_dir_release,532 .lock = v9fs_file_lock_dotl,533 .flock = v9fs_file_flock_dotl,534 .mmap = v9fs_file_mmap,535 .splice_read = v9fs_file_splice_read,536 .splice_write = iter_file_splice_write,537 .fsync = v9fs_file_fsync_dotl,538 .setlease = simple_nosetlease,539};540