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Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -07001#include <linux/ceph/ceph_debug.h>
Sage Weila8e63b72009-10-06 11:31:13 -07002
3#include <linux/exportfs.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09004#include <linux/slab.h>
Sage Weila8e63b72009-10-06 11:31:13 -07005#include <asm/unaligned.h>
6
7#include "super.h"
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -07008#include "mds_client.h"
Sage Weila8e63b72009-10-06 11:31:13 -07009
10/*
11 * NFS export support
12 *
13 * NFS re-export of a ceph mount is, at present, only semireliable.
14 * The basic issue is that the Ceph architectures doesn't lend itself
15 * well to generating filehandles that will remain valid forever.
16 *
17 * So, we do our best. If you're lucky, your inode will be in the
18 * client's cache. If it's not, and you have a connectable fh, then
19 * the MDS server may be able to find it for you. Otherwise, you get
20 * ESTALE.
21 *
22 * There are ways to this more reliable, but in the non-connectable fh
23 * case, we won't every work perfectly, and in the connectable case,
24 * some changes are needed on the MDS side to work better.
25 */
26
27/*
28 * Basic fh
29 */
30struct ceph_nfs_fh {
31 u64 ino;
32} __attribute__ ((packed));
33
34/*
35 * Larger 'connectable' fh that includes parent ino and name hash.
36 * Use this whenever possible, as it works more reliably.
37 */
38struct ceph_nfs_confh {
39 u64 ino, parent_ino;
40 u32 parent_name_hash;
41} __attribute__ ((packed));
42
43static int ceph_encode_fh(struct dentry *dentry, u32 *rawfh, int *max_len,
44 int connectable)
45{
Aneesh Kumar K.V92923dc2010-10-05 16:03:41 +053046 int type;
Sage Weila8e63b72009-10-06 11:31:13 -070047 struct ceph_nfs_fh *fh = (void *)rawfh;
48 struct ceph_nfs_confh *cfh = (void *)rawfh;
Sage Weile5f86dc2011-07-26 11:30:55 -070049 struct dentry *parent;
Sage Weila8e63b72009-10-06 11:31:13 -070050 struct inode *inode = dentry->d_inode;
Aneesh Kumar K.V92923dc2010-10-05 16:03:41 +053051 int connected_handle_length = sizeof(*cfh)/4;
52 int handle_length = sizeof(*fh)/4;
Sage Weila8e63b72009-10-06 11:31:13 -070053
54 /* don't re-export snaps */
55 if (ceph_snap(inode) != CEPH_NOSNAP)
56 return -EINVAL;
57
Sage Weile5f86dc2011-07-26 11:30:55 -070058 spin_lock(&dentry->d_lock);
59 parent = dget(dentry->d_parent);
60 spin_unlock(&dentry->d_lock);
61
Aneesh Kumar K.V92923dc2010-10-05 16:03:41 +053062 if (*max_len >= connected_handle_length) {
Sage Weila8e63b72009-10-06 11:31:13 -070063 dout("encode_fh %p connectable\n", dentry);
64 cfh->ino = ceph_ino(dentry->d_inode);
65 cfh->parent_ino = ceph_ino(parent->d_inode);
Sage Weile5f86dc2011-07-26 11:30:55 -070066 cfh->parent_name_hash = ceph_dentry_hash(parent->d_inode,
67 dentry);
Aneesh Kumar K.V92923dc2010-10-05 16:03:41 +053068 *max_len = connected_handle_length;
Sage Weila8e63b72009-10-06 11:31:13 -070069 type = 2;
Aneesh Kumar K.V92923dc2010-10-05 16:03:41 +053070 } else if (*max_len >= handle_length) {
Aneesh Kumar K.Vbba0cd02010-10-05 16:03:42 +053071 if (connectable) {
72 *max_len = connected_handle_length;
Sage Weile5f86dc2011-07-26 11:30:55 -070073 type = 255;
74 } else {
75 dout("encode_fh %p\n", dentry);
76 fh->ino = ceph_ino(dentry->d_inode);
77 *max_len = handle_length;
78 type = 1;
Aneesh Kumar K.Vbba0cd02010-10-05 16:03:42 +053079 }
Sage Weila8e63b72009-10-06 11:31:13 -070080 } else {
Aneesh Kumar K.Vbba0cd02010-10-05 16:03:42 +053081 *max_len = handle_length;
Sage Weile5f86dc2011-07-26 11:30:55 -070082 type = 255;
Sage Weila8e63b72009-10-06 11:31:13 -070083 }
Sage Weile5f86dc2011-07-26 11:30:55 -070084 dput(parent);
Sage Weila8e63b72009-10-06 11:31:13 -070085 return type;
86}
87
88/*
89 * convert regular fh to dentry
90 *
91 * FIXME: we should try harder by querying the mds for the ino.
92 */
93static struct dentry *__fh_to_dentry(struct super_block *sb,
94 struct ceph_nfs_fh *fh)
95{
Sage Weil3c454cf2011-04-06 09:31:40 -070096 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
Sage Weila8e63b72009-10-06 11:31:13 -070097 struct inode *inode;
98 struct dentry *dentry;
99 struct ceph_vino vino;
100 int err;
101
102 dout("__fh_to_dentry %llx\n", fh->ino);
103 vino.ino = fh->ino;
104 vino.snap = CEPH_NOSNAP;
105 inode = ceph_find_inode(sb, vino);
Sage Weil3c454cf2011-04-06 09:31:40 -0700106 if (!inode) {
107 struct ceph_mds_request *req;
108
109 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
110 USE_ANY_MDS);
111 if (IS_ERR(req))
112 return ERR_CAST(req);
113
114 req->r_ino1 = vino;
115 req->r_num_caps = 1;
116 err = ceph_mdsc_do_request(mdsc, NULL, req);
Sage Weil45e3d3e2011-04-06 09:35:00 -0700117 inode = req->r_target_inode;
118 if (inode)
Sage Weil70b666c2011-05-27 09:24:26 -0700119 ihold(inode);
Sage Weil3c454cf2011-04-06 09:31:40 -0700120 ceph_mdsc_put_request(req);
Sage Weil3c454cf2011-04-06 09:31:40 -0700121 if (!inode)
122 return ERR_PTR(-ESTALE);
123 }
Sage Weila8e63b72009-10-06 11:31:13 -0700124
125 dentry = d_obtain_alias(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200126 if (IS_ERR(dentry)) {
Sage Weila8e63b72009-10-06 11:31:13 -0700127 pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n",
128 fh->ino, inode);
129 iput(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200130 return dentry;
Sage Weila8e63b72009-10-06 11:31:13 -0700131 }
132 err = ceph_init_dentry(dentry);
Sage Weila8e63b72009-10-06 11:31:13 -0700133 if (err < 0) {
134 iput(inode);
135 return ERR_PTR(err);
136 }
137 dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry);
138 return dentry;
139}
140
141/*
142 * convert connectable fh to dentry
143 */
144static struct dentry *__cfh_to_dentry(struct super_block *sb,
145 struct ceph_nfs_confh *cfh)
146{
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -0700147 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
Sage Weila8e63b72009-10-06 11:31:13 -0700148 struct inode *inode;
149 struct dentry *dentry;
150 struct ceph_vino vino;
151 int err;
152
153 dout("__cfh_to_dentry %llx (%llx/%x)\n",
154 cfh->ino, cfh->parent_ino, cfh->parent_name_hash);
155
156 vino.ino = cfh->ino;
157 vino.snap = CEPH_NOSNAP;
158 inode = ceph_find_inode(sb, vino);
159 if (!inode) {
160 struct ceph_mds_request *req;
161
162 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH,
163 USE_ANY_MDS);
164 if (IS_ERR(req))
Julia Lawall7e34bc52010-05-22 12:01:14 +0200165 return ERR_CAST(req);
Sage Weila8e63b72009-10-06 11:31:13 -0700166
167 req->r_ino1 = vino;
168 req->r_ino2.ino = cfh->parent_ino;
169 req->r_ino2.snap = CEPH_NOSNAP;
170 req->r_path2 = kmalloc(16, GFP_NOFS);
171 snprintf(req->r_path2, 16, "%d", cfh->parent_name_hash);
172 req->r_num_caps = 1;
173 err = ceph_mdsc_do_request(mdsc, NULL, req);
Sage Weil45e3d3e2011-04-06 09:35:00 -0700174 inode = req->r_target_inode;
175 if (inode)
Sage Weil70b666c2011-05-27 09:24:26 -0700176 ihold(inode);
Sage Weila8e63b72009-10-06 11:31:13 -0700177 ceph_mdsc_put_request(req);
Sage Weila8e63b72009-10-06 11:31:13 -0700178 if (!inode)
179 return ERR_PTR(err ? err : -ESTALE);
180 }
181
182 dentry = d_obtain_alias(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200183 if (IS_ERR(dentry)) {
Sage Weila8e63b72009-10-06 11:31:13 -0700184 pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n",
185 cfh->ino, inode);
186 iput(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200187 return dentry;
Sage Weila8e63b72009-10-06 11:31:13 -0700188 }
189 err = ceph_init_dentry(dentry);
190 if (err < 0) {
191 iput(inode);
192 return ERR_PTR(err);
193 }
194 dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry);
195 return dentry;
196}
197
198static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid,
199 int fh_len, int fh_type)
200{
201 if (fh_type == 1)
202 return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw);
203 else
204 return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw);
205}
206
207/*
208 * get parent, if possible.
209 *
210 * FIXME: we could do better by querying the mds to discover the
211 * parent.
212 */
213static struct dentry *ceph_fh_to_parent(struct super_block *sb,
214 struct fid *fid,
215 int fh_len, int fh_type)
216{
217 struct ceph_nfs_confh *cfh = (void *)fid->raw;
218 struct ceph_vino vino;
219 struct inode *inode;
220 struct dentry *dentry;
221 int err;
222
223 if (fh_type == 1)
224 return ERR_PTR(-ESTALE);
225
226 pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino,
227 cfh->parent_name_hash);
228
229 vino.ino = cfh->ino;
230 vino.snap = CEPH_NOSNAP;
231 inode = ceph_find_inode(sb, vino);
232 if (!inode)
233 return ERR_PTR(-ESTALE);
234
235 dentry = d_obtain_alias(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200236 if (IS_ERR(dentry)) {
Sage Weila8e63b72009-10-06 11:31:13 -0700237 pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n",
238 cfh->ino, inode);
239 iput(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200240 return dentry;
Sage Weila8e63b72009-10-06 11:31:13 -0700241 }
242 err = ceph_init_dentry(dentry);
243 if (err < 0) {
244 iput(inode);
245 return ERR_PTR(err);
246 }
247 dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry);
248 return dentry;
249}
250
251const struct export_operations ceph_export_ops = {
252 .encode_fh = ceph_encode_fh,
253 .fh_to_dentry = ceph_fh_to_dentry,
254 .fh_to_parent = ceph_fh_to_parent,
255};