blob: 8e1b60e557b65bea0df86a881376456658a9cffd [file] [log] [blame]
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
Sage Weilc8628682012-04-05 12:07:36 -070043/*
44 * The presence of @parent_inode here tells us whether NFS wants a
45 * connectable file handle. However, we want to make a connectionable
46 * file handle unconditionally so that the MDS gets as much of a hint
47 * as possible. That means we only use @parent_dentry to indicate
48 * whether nfsd wants a connectable fh, and whether we should indicate
49 * failure from a too-small @max_len.
50 */
51static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
52 struct inode *parent_inode)
Sage Weila8e63b72009-10-06 11:31:13 -070053{
Aneesh Kumar K.V92923dc2010-10-05 16:03:41 +053054 int type;
Sage Weila8e63b72009-10-06 11:31:13 -070055 struct ceph_nfs_fh *fh = (void *)rawfh;
56 struct ceph_nfs_confh *cfh = (void *)rawfh;
Aneesh Kumar K.V92923dc2010-10-05 16:03:41 +053057 int connected_handle_length = sizeof(*cfh)/4;
58 int handle_length = sizeof(*fh)/4;
Sage Weilc8628682012-04-05 12:07:36 -070059 struct dentry *dentry = d_find_alias(inode);
60 struct dentry *parent;
Sage Weila8e63b72009-10-06 11:31:13 -070061
62 /* don't re-export snaps */
63 if (ceph_snap(inode) != CEPH_NOSNAP)
64 return -EINVAL;
65
Sage Weilc8628682012-04-05 12:07:36 -070066 /* if we found an alias, generate a connectable fh */
67 if (*max_len >= connected_handle_length && dentry) {
Sage Weila8e63b72009-10-06 11:31:13 -070068 dout("encode_fh %p connectable\n", dentry);
Sage Weilc8628682012-04-05 12:07:36 -070069 spin_lock(&dentry->d_lock);
70 parent = dentry->d_parent;
71 cfh->ino = ceph_ino(inode);
Sage Weila8e63b72009-10-06 11:31:13 -070072 cfh->parent_ino = ceph_ino(parent->d_inode);
Sage Weile5f86dc2011-07-26 11:30:55 -070073 cfh->parent_name_hash = ceph_dentry_hash(parent->d_inode,
74 dentry);
Aneesh Kumar K.V92923dc2010-10-05 16:03:41 +053075 *max_len = connected_handle_length;
Sage Weila8e63b72009-10-06 11:31:13 -070076 type = 2;
Sage Weilc8628682012-04-05 12:07:36 -070077 spin_unlock(&dentry->d_lock);
Aneesh Kumar K.V92923dc2010-10-05 16:03:41 +053078 } else if (*max_len >= handle_length) {
Sage Weilc8628682012-04-05 12:07:36 -070079 if (parent_inode) {
80 /* nfsd wants connectable */
Aneesh Kumar K.Vbba0cd02010-10-05 16:03:42 +053081 *max_len = connected_handle_length;
Sage Weile5f86dc2011-07-26 11:30:55 -070082 type = 255;
83 } else {
84 dout("encode_fh %p\n", dentry);
Sage Weilc8628682012-04-05 12:07:36 -070085 fh->ino = ceph_ino(inode);
Sage Weile5f86dc2011-07-26 11:30:55 -070086 *max_len = handle_length;
87 type = 1;
Aneesh Kumar K.Vbba0cd02010-10-05 16:03:42 +053088 }
Sage Weila8e63b72009-10-06 11:31:13 -070089 } else {
Aneesh Kumar K.Vbba0cd02010-10-05 16:03:42 +053090 *max_len = handle_length;
Sage Weile5f86dc2011-07-26 11:30:55 -070091 type = 255;
Sage Weila8e63b72009-10-06 11:31:13 -070092 }
93 return type;
94}
95
96/*
97 * convert regular fh to dentry
98 *
99 * FIXME: we should try harder by querying the mds for the ino.
100 */
101static struct dentry *__fh_to_dentry(struct super_block *sb,
102 struct ceph_nfs_fh *fh)
103{
Sage Weil3c454cf2011-04-06 09:31:40 -0700104 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
Sage Weila8e63b72009-10-06 11:31:13 -0700105 struct inode *inode;
106 struct dentry *dentry;
107 struct ceph_vino vino;
108 int err;
109
110 dout("__fh_to_dentry %llx\n", fh->ino);
111 vino.ino = fh->ino;
112 vino.snap = CEPH_NOSNAP;
113 inode = ceph_find_inode(sb, vino);
Sage Weil3c454cf2011-04-06 09:31:40 -0700114 if (!inode) {
115 struct ceph_mds_request *req;
116
117 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
118 USE_ANY_MDS);
119 if (IS_ERR(req))
120 return ERR_CAST(req);
121
122 req->r_ino1 = vino;
123 req->r_num_caps = 1;
124 err = ceph_mdsc_do_request(mdsc, NULL, req);
Sage Weil45e3d3e2011-04-06 09:35:00 -0700125 inode = req->r_target_inode;
126 if (inode)
Sage Weil70b666c2011-05-27 09:24:26 -0700127 ihold(inode);
Sage Weil3c454cf2011-04-06 09:31:40 -0700128 ceph_mdsc_put_request(req);
Sage Weil3c454cf2011-04-06 09:31:40 -0700129 if (!inode)
130 return ERR_PTR(-ESTALE);
131 }
Sage Weila8e63b72009-10-06 11:31:13 -0700132
133 dentry = d_obtain_alias(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200134 if (IS_ERR(dentry)) {
Sage Weila8e63b72009-10-06 11:31:13 -0700135 pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n",
136 fh->ino, inode);
137 iput(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200138 return dentry;
Sage Weila8e63b72009-10-06 11:31:13 -0700139 }
140 err = ceph_init_dentry(dentry);
Sage Weila8e63b72009-10-06 11:31:13 -0700141 if (err < 0) {
142 iput(inode);
143 return ERR_PTR(err);
144 }
145 dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry);
146 return dentry;
147}
148
149/*
150 * convert connectable fh to dentry
151 */
152static struct dentry *__cfh_to_dentry(struct super_block *sb,
153 struct ceph_nfs_confh *cfh)
154{
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -0700155 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
Sage Weila8e63b72009-10-06 11:31:13 -0700156 struct inode *inode;
157 struct dentry *dentry;
158 struct ceph_vino vino;
159 int err;
160
161 dout("__cfh_to_dentry %llx (%llx/%x)\n",
162 cfh->ino, cfh->parent_ino, cfh->parent_name_hash);
163
164 vino.ino = cfh->ino;
165 vino.snap = CEPH_NOSNAP;
166 inode = ceph_find_inode(sb, vino);
167 if (!inode) {
168 struct ceph_mds_request *req;
169
170 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH,
171 USE_ANY_MDS);
172 if (IS_ERR(req))
Julia Lawall7e34bc52010-05-22 12:01:14 +0200173 return ERR_CAST(req);
Sage Weila8e63b72009-10-06 11:31:13 -0700174
175 req->r_ino1 = vino;
176 req->r_ino2.ino = cfh->parent_ino;
177 req->r_ino2.snap = CEPH_NOSNAP;
178 req->r_path2 = kmalloc(16, GFP_NOFS);
179 snprintf(req->r_path2, 16, "%d", cfh->parent_name_hash);
180 req->r_num_caps = 1;
181 err = ceph_mdsc_do_request(mdsc, NULL, req);
Sage Weil45e3d3e2011-04-06 09:35:00 -0700182 inode = req->r_target_inode;
183 if (inode)
Sage Weil70b666c2011-05-27 09:24:26 -0700184 ihold(inode);
Sage Weila8e63b72009-10-06 11:31:13 -0700185 ceph_mdsc_put_request(req);
Sage Weila8e63b72009-10-06 11:31:13 -0700186 if (!inode)
187 return ERR_PTR(err ? err : -ESTALE);
188 }
189
190 dentry = d_obtain_alias(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200191 if (IS_ERR(dentry)) {
Sage Weila8e63b72009-10-06 11:31:13 -0700192 pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n",
193 cfh->ino, inode);
194 iput(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200195 return dentry;
Sage Weila8e63b72009-10-06 11:31:13 -0700196 }
197 err = ceph_init_dentry(dentry);
198 if (err < 0) {
199 iput(inode);
200 return ERR_PTR(err);
201 }
202 dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry);
203 return dentry;
204}
205
206static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid,
207 int fh_len, int fh_type)
208{
209 if (fh_type == 1)
210 return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw);
211 else
212 return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw);
213}
214
215/*
216 * get parent, if possible.
217 *
218 * FIXME: we could do better by querying the mds to discover the
219 * parent.
220 */
221static struct dentry *ceph_fh_to_parent(struct super_block *sb,
222 struct fid *fid,
223 int fh_len, int fh_type)
224{
225 struct ceph_nfs_confh *cfh = (void *)fid->raw;
226 struct ceph_vino vino;
227 struct inode *inode;
228 struct dentry *dentry;
229 int err;
230
231 if (fh_type == 1)
232 return ERR_PTR(-ESTALE);
233
234 pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino,
235 cfh->parent_name_hash);
236
237 vino.ino = cfh->ino;
238 vino.snap = CEPH_NOSNAP;
239 inode = ceph_find_inode(sb, vino);
240 if (!inode)
241 return ERR_PTR(-ESTALE);
242
243 dentry = d_obtain_alias(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200244 if (IS_ERR(dentry)) {
Sage Weila8e63b72009-10-06 11:31:13 -0700245 pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n",
246 cfh->ino, inode);
247 iput(inode);
Dan Carpenter0d509c92010-04-21 12:31:13 +0200248 return dentry;
Sage Weila8e63b72009-10-06 11:31:13 -0700249 }
250 err = ceph_init_dentry(dentry);
251 if (err < 0) {
252 iput(inode);
253 return ERR_PTR(err);
254 }
255 dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry);
256 return dentry;
257}
258
259const struct export_operations ceph_export_ops = {
260 .encode_fh = ceph_encode_fh,
Sage Weila8e63b72009-10-06 11:31:13 -0700261 .fh_to_dentry = ceph_fh_to_dentry,
262 .fh_to_parent = ceph_fh_to_parent,
263};