Root/fs/coda/cnode.c

1/* cnode related routines for the coda kernel code
2   (C) 1996 Peter Braam
3   */
4
5#include <linux/types.h>
6#include <linux/string.h>
7#include <linux/time.h>
8
9#include <linux/coda.h>
10#include <linux/coda_psdev.h>
11#include "coda_linux.h"
12
13static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
14{
15    return memcmp(fid1, fid2, sizeof(*fid1)) == 0;
16}
17
18static const struct inode_operations coda_symlink_inode_operations = {
19    .readlink = generic_readlink,
20    .follow_link = page_follow_link_light,
21    .put_link = page_put_link,
22    .setattr = coda_setattr,
23};
24
25/* cnode.c */
26static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr)
27{
28        coda_vattr_to_iattr(inode, attr);
29
30        if (S_ISREG(inode->i_mode)) {
31                inode->i_op = &coda_file_inode_operations;
32                inode->i_fop = &coda_file_operations;
33        } else if (S_ISDIR(inode->i_mode)) {
34                inode->i_op = &coda_dir_inode_operations;
35                inode->i_fop = &coda_dir_operations;
36        } else if (S_ISLNK(inode->i_mode)) {
37        inode->i_op = &coda_symlink_inode_operations;
38        inode->i_data.a_ops = &coda_symlink_aops;
39        inode->i_mapping = &inode->i_data;
40    } else
41                init_special_inode(inode, inode->i_mode, huge_decode_dev(attr->va_rdev));
42}
43
44static int coda_test_inode(struct inode *inode, void *data)
45{
46    struct CodaFid *fid = (struct CodaFid *)data;
47    struct coda_inode_info *cii = ITOC(inode);
48    return coda_fideq(&cii->c_fid, fid);
49}
50
51static int coda_set_inode(struct inode *inode, void *data)
52{
53    struct CodaFid *fid = (struct CodaFid *)data;
54    struct coda_inode_info *cii = ITOC(inode);
55    cii->c_fid = *fid;
56    return 0;
57}
58
59struct inode * coda_iget(struct super_block * sb, struct CodaFid * fid,
60             struct coda_vattr * attr)
61{
62    struct inode *inode;
63    struct coda_inode_info *cii;
64    unsigned long hash = coda_f2i(fid);
65
66    inode = iget5_locked(sb, hash, coda_test_inode, coda_set_inode, fid);
67
68    if (!inode)
69        return ERR_PTR(-ENOMEM);
70
71    if (inode->i_state & I_NEW) {
72        cii = ITOC(inode);
73        /* we still need to set i_ino for things like stat(2) */
74        inode->i_ino = hash;
75        /* inode is locked and unique, no need to grab cii->c_lock */
76        cii->c_mapcount = 0;
77        unlock_new_inode(inode);
78    }
79
80    /* always replace the attributes, type might have changed */
81    coda_fill_inode(inode, attr);
82    return inode;
83}
84
85/* this is effectively coda_iget:
86   - get attributes (might be cached)
87   - get the inode for the fid using vfs iget
88   - link the two up if this is needed
89   - fill in the attributes
90*/
91int coda_cnode_make(struct inode **inode, struct CodaFid *fid, struct super_block *sb)
92{
93        struct coda_vattr attr;
94        int error;
95        
96    /* We get inode numbers from Venus -- see venus source */
97    error = venus_getattr(sb, fid, &attr);
98    if ( error ) {
99        *inode = NULL;
100        return error;
101    }
102
103    *inode = coda_iget(sb, fid, &attr);
104    if ( IS_ERR(*inode) ) {
105        printk("coda_cnode_make: coda_iget failed\n");
106                return PTR_ERR(*inode);
107        }
108    return 0;
109}
110
111
112/* Although we treat Coda file identifiers as immutable, there is one
113 * special case for files created during a disconnection where they may
114 * not be globally unique. When an identifier collision is detected we
115 * first try to flush the cached inode from the kernel and finally
116 * resort to renaming/rehashing in-place. Userspace remembers both old
117 * and new values of the identifier to handle any in-flight upcalls.
118 * The real solution is to use globally unique UUIDs as identifiers, but
119 * retrofitting the existing userspace code for this is non-trivial. */
120void coda_replace_fid(struct inode *inode, struct CodaFid *oldfid,
121              struct CodaFid *newfid)
122{
123    struct coda_inode_info *cii = ITOC(inode);
124    unsigned long hash = coda_f2i(newfid);
125    
126    BUG_ON(!coda_fideq(&cii->c_fid, oldfid));
127
128    /* replace fid and rehash inode */
129    /* XXX we probably need to hold some lock here! */
130    remove_inode_hash(inode);
131    cii->c_fid = *newfid;
132    inode->i_ino = hash;
133    __insert_inode_hash(inode, hash);
134}
135
136/* convert a fid to an inode. */
137struct inode *coda_fid_to_inode(struct CodaFid *fid, struct super_block *sb)
138{
139    struct inode *inode;
140    unsigned long hash = coda_f2i(fid);
141
142    if ( !sb ) {
143        printk("coda_fid_to_inode: no sb!\n");
144        return NULL;
145    }
146
147    inode = ilookup5(sb, hash, coda_test_inode, fid);
148    if ( !inode )
149        return NULL;
150
151    /* we should never see newly created inodes because we intentionally
152     * fail in the initialization callback */
153    BUG_ON(inode->i_state & I_NEW);
154
155    return inode;
156}
157
158/* the CONTROL inode is made without asking attributes from Venus */
159int coda_cnode_makectl(struct inode **inode, struct super_block *sb)
160{
161    int error = -ENOMEM;
162
163    *inode = new_inode(sb);
164    if (*inode) {
165        (*inode)->i_ino = CTL_INO;
166        (*inode)->i_op = &coda_ioctl_inode_operations;
167        (*inode)->i_fop = &coda_ioctl_operations;
168        (*inode)->i_mode = 0444;
169        error = 0;
170    }
171
172    return error;
173}
174
175

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