vfs_file.rar_VFS

/* * linux/fs/9p/vfs_file.c * * 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> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to: * Free Software Foundation * 51 Franklin Street, Fifth Floor * Boston, MA 02111-1301 USA * */ #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 <asm/uaccess.h> #include <linux/idr.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; 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->f_path.dentry); 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. */ fid = v9fs_writeback_fid(file->f_path.dentry); if (IS_ERR(fid)) { err = PTR_ERR(fid); mutex_unlock(&v9inode->v_mutex); goto out_error; } v9inode->writeback_fid = (void *) fid; } mutex_unlock(&v9inode->v_mutex); if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) v9fs_cache_inode_set_cookie(inode, file); 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) { int res = 0; struct inode *inode = file_inode(filp); p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl); /* No mandatory locks */ if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) return -ENOLCK; 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 res; } 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; int res = 0; unsigned char fl_type; fid = filp->private_data; BUG_ON(fid == NULL); if ((fl->fl_flags & FL_POSIX) != FL_POSIX) BUG(); res = posix_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; /* * 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) break; if (status != P9_LOCK_BLOCKED) break; if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd)) break; if (schedule_timeout_interruptible(P9_LOCK_TIMEOUT) != 0) break; } /* map 9p status to VFS status */ switch (status) { case P9_LOCK_SUCCESS: res = 0; break; case P9_LOCK_BLOCKED: res = -EAGAIN; break; case P9_LOCK_ERROR: case P9_LOCK_GRACE: res = -ENOLCK; break; default: BUG(); } /* * 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; res = posix_lock_file_wait(filp, fl); fl->fl_type = fl_type; } 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) return res; /* 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; } 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); /* No mandatory locks */ if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) 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); } 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; out_err: 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