xref: /linux/fs/9p/v9fs_vfs.h (revision 8f8d5745bb520c76b81abef4a2cb3023d0313bfd)
1 /*
2  * V9FS VFS extensions.
3  *
4  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
5  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
6  *
7  *  This program is free software; you can redistribute it and/or modify
8  *  it under the terms of the GNU General Public License version 2
9  *  as published by the Free Software Foundation.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, write to:
18  *  Free Software Foundation
19  *  51 Franklin Street, Fifth Floor
20  *  Boston, MA  02111-1301  USA
21  *
22  */
23 #ifndef FS_9P_V9FS_VFS_H
24 #define FS_9P_V9FS_VFS_H
25 
26 /* plan9 semantics are that created files are implicitly opened.
27  * But linux semantics are that you call create, then open.
28  * the plan9 approach is superior as it provides an atomic
29  * open.
30  * we track the create fid here. When the file is opened, if fidopen is
31  * non-zero, we use the fid and can skip some steps.
32  * there may be a better way to do this, but I don't know it.
33  * one BAD way is to clunk the fid on create, then open it again:
34  * you lose the atomicity of file open
35  */
36 
37 /* special case:
38  * unlink calls remove, which is an implicit clunk. So we have to track
39  * that kind of thing so that we don't try to clunk a dead fid.
40  */
41 #define P9_LOCK_TIMEOUT (30*HZ)
42 
43 /* flags for v9fs_stat2inode() & v9fs_stat2inode_dotl() */
44 #define V9FS_STAT2INODE_KEEP_ISIZE 1
45 
46 extern struct file_system_type v9fs_fs_type;
47 extern const struct address_space_operations v9fs_addr_operations;
48 extern const struct file_operations v9fs_file_operations;
49 extern const struct file_operations v9fs_file_operations_dotl;
50 extern const struct file_operations v9fs_dir_operations;
51 extern const struct file_operations v9fs_dir_operations_dotl;
52 extern const struct dentry_operations v9fs_dentry_operations;
53 extern const struct dentry_operations v9fs_cached_dentry_operations;
54 extern const struct file_operations v9fs_cached_file_operations;
55 extern const struct file_operations v9fs_cached_file_operations_dotl;
56 extern const struct file_operations v9fs_mmap_file_operations;
57 extern const struct file_operations v9fs_mmap_file_operations_dotl;
58 extern struct kmem_cache *v9fs_inode_cache;
59 
60 struct inode *v9fs_alloc_inode(struct super_block *sb);
61 void v9fs_destroy_inode(struct inode *inode);
62 struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t);
63 int v9fs_init_inode(struct v9fs_session_info *v9ses,
64 		    struct inode *inode, umode_t mode, dev_t);
65 void v9fs_evict_inode(struct inode *inode);
66 ino_t v9fs_qid2ino(struct p9_qid *qid);
67 void v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
68 		      struct super_block *sb, unsigned int flags);
69 void v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
70 			   unsigned int flags);
71 int v9fs_dir_release(struct inode *inode, struct file *filp);
72 int v9fs_file_open(struct inode *inode, struct file *file);
73 void v9fs_inode2stat(struct inode *inode, struct p9_wstat *stat);
74 int v9fs_uflags2omode(int uflags, int extended);
75 
76 void v9fs_blank_wstat(struct p9_wstat *wstat);
77 int v9fs_vfs_setattr_dotl(struct dentry *, struct iattr *);
78 int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
79 			 int datasync);
80 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode);
81 int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode);
82 static inline void v9fs_invalidate_inode_attr(struct inode *inode)
83 {
84 	struct v9fs_inode *v9inode;
85 	v9inode = V9FS_I(inode);
86 	v9inode->cache_validity |= V9FS_INO_INVALID_ATTR;
87 	return;
88 }
89 
90 int v9fs_open_to_dotl_flags(int flags);
91 
92 static inline void v9fs_i_size_write(struct inode *inode, loff_t i_size)
93 {
94 	/*
95 	 * 32-bit need the lock, concurrent updates could break the
96 	 * sequences and make i_size_read() loop forever.
97 	 * 64-bit updates are atomic and can skip the locking.
98 	 */
99 	if (sizeof(i_size) > sizeof(long))
100 		spin_lock(&inode->i_lock);
101 	i_size_write(inode, i_size);
102 	if (sizeof(i_size) > sizeof(long))
103 		spin_unlock(&inode->i_lock);
104 }
105 #endif
106