// 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/sched.h> #include <linux/file.h> #include <linux/stat.h> #include <linux/string.h> #include <linux/inet.h> #include <linux/list.h> #include <linux/pagemap.h> #include <linux/utsname.h> #include <linux/uaccess.h> #include <linux/idr.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_file_vm_ops; 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_inode *v9inode; struct v9fs_session_info *v9ses; struct p9_fid *fid, *writeback_fid; int omode; p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file); v9inode = V9FS_I(inode); v9ses = v9fs_inode2v9ses(inode); if (v9fs_proto_dotl(v9ses)) omode = v9fs_open_to_dotl_flags(file->f_flags); else omode = v9fs_uflags2omode(file->f_flags, v9fs_proto_dotu(v9ses)); fid = file->private_data; if (!fid) { fid = v9fs_fid_clone(file_dentry(file)); if (IS_ERR(fid)) return PTR_ERR(fid); err = p9_client_open(fid, omode); if (err < 0) { p9_client_clunk(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; mutex_lock(&v9inode->v_mutex); if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) && !v9inode->writeback_fid && ((file->f_flags & O_ACCMODE) != O_RDONLY)) { /* * clone a fid and add it to writeback_fid * we do it during open time instead of * page dirty time via write_begin/page_mkwrite * because we want write after unlink usecase * to work. */ writeback_fid = v9fs_writeback_fid(file_dentry(file)); if (IS_ERR(writeback_fid)) { err = PTR_ERR(writeback_fid); mutex_unlock(&v9inode->v_mutex); goto out_error; } v9inode->writeback_fid = (void *) writeback_fid; } mutex_unlock(&v9inode->v_mutex); if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) fscache_use_cookie(v9fs_inode_cookie(v9inode), file->f_mode & FMODE_WRITE); v9fs_open_fid_add(inode, fid); return 0; out_error: p9_client_clunk(file->private_data); file->private_data = NULL; return err; } /** * 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->fl_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; unsigned char fl_type; struct v9fs_session_info *v9ses; fid = filp->private_data; BUG_ON(fid == NULL); BUG_ON((fl->fl_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->fl_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->fl_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: WARN_ONCE(1, "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->fl_type != F_UNLCK) { fl_type = fl->fl_type; fl->fl_type = F_UNLCK; /* Even if this fails we want to return the remote error */ locks_lock_file_wait(filp, fl); fl->fl_type = fl_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->fl_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->fl_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->fl_type = F_RDLCK; break; case P9_LOCK_TYPE_WRLCK: fl->fl_type = F_WRLCK; break; case P9_LOCK_TYPE_UNLCK: fl->fl_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->fl_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->fl_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->fl_flags & FL_FLOCK)) goto out_err; if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) { filemap_write_and_wait(inode->i_mapping); invalidate_mapping_pages(&inode->i_data, 0, -1); } /* Convert flock to posix lock */ fl->fl_flags |= FL_POSIX; fl->fl_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; int ret, err = 0; p9_debug(P9_DEBUG_VFS, "count %zu offset %lld\n", iov_iter_count(to), iocb->ki_pos); if (iocb->ki_filp->f_flags & O_NONBLOCK) ret = p9_client_read_once(fid, iocb->ki_pos, to, &err); else ret = p9_client_read(fid, iocb->ki_pos, to, &err); if (!ret) return err; iocb->ki_pos += ret; return ret; } /** * 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; ssize_t retval; loff_t origin; int err = 0; retval = generic_write_checks(iocb, from); if (retval <= 0) return retval; origin = iocb->ki_pos; retval = p9_client_write(file->private_data, iocb->ki_pos, from, &err); if (retval > 0) { struct inode *inode = file_inode(file); loff_t i_size; unsigned long pg_start, pg_end; pg_start = origin >> PAGE_SHIFT; pg_end = (origin + retval - 1) >> PAGE_SHIFT; if (inode->i_mapping && inode->i_mapping->nrpages) invalidate_inode_pages2_range(inode->i_mapping, pg_start, pg_end); iocb->ki_pos += retval; i_size = i_size_read(inode); if (iocb->ki_pos > i_size) { inode_add_bytes(inode, iocb->ki_pos - i_size); /* * Need to serialize against i_size_write() in * v9fs_stat2inode() */ v9fs_i_size_write(inode, iocb->ki_pos); } return retval; } return err; } 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(struct file *filp, struct vm_area_struct *vma) { int retval; retval = generic_file_mmap(filp, vma); if (!retval) vma->vm_ops = &v9fs_file_vm_ops; return retval; } static int v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma) { int retval; struct inode *inode; struct v9fs_inode *v9inode; struct p9_fid *fid; inode = file_inode(filp); v9inode = V9FS_I(inode); mutex_lock(&v9inode->v_mutex); if (!v9inode->writeback_fid && (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE)) { /* * clone a fid and add it to writeback_fid * we do it during mmap instead of * page dirty time via write_begin/page_mkwrite * because we want write after unlink usecase * to work. */ fid = v9fs_writeback_fid(file_dentry(filp)); if (IS_ERR(fid)) { retval = PTR_ERR(fid); mutex_unlock(&v9inode->v_mutex); return retval; } v9inode->writeback_fid = (void *) fid; } mutex_unlock(&v9inode->v_mutex); retval = generic_file_mmap(filp, vma); if (!retval) vma->vm_ops = &v9fs_mmap_file_vm_ops; return retval; } static vm_fault_t v9fs_vm_page_mkwrite(struct vm_fault *vmf) { struct v9fs_inode *v9inode; struct folio *folio = page_folio(vmf->page); struct file *filp = vmf->vma->vm_file; struct inode *inode = file_inode(filp); p9_debug(P9_DEBUG_VFS, "folio %p fid %lx\n", folio, (unsigned long)filp->private_data); v9inode = V9FS_I(inode); /* Wait for the page to be written to the cache before we allow it to * be modified. We then assume the entire page will need writing back. */ #ifdef CONFIG_9P_FSCACHE if (folio_test_fscache(folio) && folio_wait_fscache_killable(folio) < 0) return VM_FAULT_NOPAGE; #endif /* Update file times before taking page lock */ file_update_time(filp); BUG_ON(!v9inode->writeback_fid); if (folio_lock_killable(folio) < 0) return VM_FAULT_RETRY; if (folio_mapping(folio) != inode->i_mapping) goto out_unlock; folio_wait_stable(folio); return VM_FAULT_LOCKED; out_unlock: folio_unlock(folio); return VM_FAULT_NOPAGE; } /** * v9fs_mmap_file_read_iter - read from a file * @iocb: The operation parameters * @to: The buffer to read into * */ static ssize_t v9fs_mmap_file_read_iter(struct kiocb *iocb, struct iov_iter *to) { /* TODO: Check if there are dirty pages */ return v9fs_file_read_iter(iocb, to); } /** * v9fs_mmap_file_write_iter - write to a file * @iocb: The operation parameters * @from: The data to write * */ static ssize_t v9fs_mmap_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { /* * TODO: invalidate mmaps on filp's inode between * offset and offset+count */ return v9fs_file_write_iter(iocb, from); } static void v9fs_mmap_vm_close(struct vm_area_struct *vma) { struct inode *inode; struct writeback_control wbc = { .nr_to_write = LONG_MAX, .sync_mode = WB_SYNC_ALL, .range_start = (loff_t)vma->vm_pgoff * PAGE_SIZE, /* absolute end, byte at end included */ .range_end = (loff_t)vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start - 1), }; if (!(vma->vm_flags & VM_SHARED)) return; p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma); inode = file_inode(vma->vm_file); filemap_fdatawrite_wbc(inode->i_mapping, &wbc); } static const struct vm_operations_struct v9fs_file_vm_ops = { .fault = filemap_fault, .map_pages = filemap_map_pages, .page_mkwrite = v9fs_vm_page_mkwrite, }; 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_cached_file_operations = { .llseek = generic_file_llseek, .read_iter = generic_file_read_iter, .write_iter = generic_file_write_iter, .open = v9fs_file_open, .release = v9fs_dir_release, .lock = v9fs_file_lock, .mmap = v9fs_file_mmap, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .fsync = v9fs_file_fsync, }; const struct file_operations v9fs_cached_file_operations_dotl = { .llseek = generic_file_llseek, .read_iter = generic_file_read_iter, .write_iter = generic_file_write_iter, .open = v9fs_file_open, .release = v9fs_dir_release, .lock = v9fs_file_lock_dotl, .flock = v9fs_file_flock_dotl, .mmap = v9fs_file_mmap, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .fsync = v9fs_file_fsync_dotl, }; 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 = generic_file_readonly_mmap, .splice_read = generic_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 = generic_file_readonly_mmap, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .fsync = v9fs_file_fsync_dotl, }; const struct file_operations v9fs_mmap_file_operations = { .llseek = generic_file_llseek, .read_iter = v9fs_mmap_file_read_iter, .write_iter = v9fs_mmap_file_write_iter, .open = v9fs_file_open, .release = v9fs_dir_release, .lock = v9fs_file_lock, .mmap = v9fs_mmap_file_mmap, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .fsync = v9fs_file_fsync, }; const struct file_operations v9fs_mmap_file_operations_dotl = { .llseek = generic_file_llseek, .read_iter = v9fs_mmap_file_read_iter, .write_iter = v9fs_mmap_file_write_iter, .open = v9fs_file_open, .release = v9fs_dir_release, .lock = v9fs_file_lock_dotl, .flock = v9fs_file_flock_dotl, .mmap = v9fs_mmap_file_mmap, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .fsync = v9fs_file_fsync_dotl, };