1 #include <linux/ceph/ceph_debug.h>
3 #include <linux/exportfs.h>
4 #include <linux/slab.h>
5 #include <asm/unaligned.h>
8 #include "mds_client.h"
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.
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
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.
32 } __attribute__ ((packed));
35 * Larger 'connectable' fh that includes parent ino and name hash.
36 * Use this whenever possible, as it works more reliably.
38 struct ceph_nfs_confh {
41 } __attribute__ ((packed));
43 static int ceph_encode_fh(struct dentry *dentry, u32 *rawfh, int *max_len,
47 struct ceph_nfs_fh *fh = (void *)rawfh;
48 struct ceph_nfs_confh *cfh = (void *)rawfh;
49 struct dentry *parent;
50 struct inode *inode = dentry->d_inode;
51 int connected_handle_length = sizeof(*cfh)/4;
52 int handle_length = sizeof(*fh)/4;
54 /* don't re-export snaps */
55 if (ceph_snap(inode) != CEPH_NOSNAP)
58 spin_lock(&dentry->d_lock);
59 parent = dget(dentry->d_parent);
60 spin_unlock(&dentry->d_lock);
62 if (*max_len >= connected_handle_length) {
63 dout("encode_fh %p connectable\n", dentry);
64 cfh->ino = ceph_ino(dentry->d_inode);
65 cfh->parent_ino = ceph_ino(parent->d_inode);
66 cfh->parent_name_hash = ceph_dentry_hash(parent->d_inode,
68 *max_len = connected_handle_length;
70 } else if (*max_len >= handle_length) {
72 *max_len = connected_handle_length;
75 dout("encode_fh %p\n", dentry);
76 fh->ino = ceph_ino(dentry->d_inode);
77 *max_len = handle_length;
81 *max_len = handle_length;
89 * convert regular fh to dentry
91 * FIXME: we should try harder by querying the mds for the ino.
93 static struct dentry *__fh_to_dentry(struct super_block *sb,
94 struct ceph_nfs_fh *fh)
96 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
98 struct dentry *dentry;
99 struct ceph_vino vino;
102 dout("__fh_to_dentry %llx\n", fh->ino);
104 vino.snap = CEPH_NOSNAP;
105 inode = ceph_find_inode(sb, vino);
107 struct ceph_mds_request *req;
109 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
112 return ERR_CAST(req);
116 err = ceph_mdsc_do_request(mdsc, NULL, req);
117 inode = req->r_target_inode;
120 ceph_mdsc_put_request(req);
122 return ERR_PTR(-ESTALE);
125 dentry = d_obtain_alias(inode);
126 if (IS_ERR(dentry)) {
127 pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n",
132 err = ceph_init_dentry(dentry);
137 dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry);
142 * convert connectable fh to dentry
144 static struct dentry *__cfh_to_dentry(struct super_block *sb,
145 struct ceph_nfs_confh *cfh)
147 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
149 struct dentry *dentry;
150 struct ceph_vino vino;
153 dout("__cfh_to_dentry %llx (%llx/%x)\n",
154 cfh->ino, cfh->parent_ino, cfh->parent_name_hash);
157 vino.snap = CEPH_NOSNAP;
158 inode = ceph_find_inode(sb, vino);
160 struct ceph_mds_request *req;
162 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH,
165 return ERR_CAST(req);
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);
173 err = ceph_mdsc_do_request(mdsc, NULL, req);
174 inode = req->r_target_inode;
177 ceph_mdsc_put_request(req);
179 return ERR_PTR(err ? err : -ESTALE);
182 dentry = d_obtain_alias(inode);
183 if (IS_ERR(dentry)) {
184 pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n",
189 err = ceph_init_dentry(dentry);
194 dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry);
198 static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid,
199 int fh_len, int fh_type)
202 return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw);
204 return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw);
208 * get parent, if possible.
210 * FIXME: we could do better by querying the mds to discover the
213 static struct dentry *ceph_fh_to_parent(struct super_block *sb,
215 int fh_len, int fh_type)
217 struct ceph_nfs_confh *cfh = (void *)fid->raw;
218 struct ceph_vino vino;
220 struct dentry *dentry;
224 return ERR_PTR(-ESTALE);
226 pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino,
227 cfh->parent_name_hash);
230 vino.snap = CEPH_NOSNAP;
231 inode = ceph_find_inode(sb, vino);
233 return ERR_PTR(-ESTALE);
235 dentry = d_obtain_alias(inode);
236 if (IS_ERR(dentry)) {
237 pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n",
242 err = ceph_init_dentry(dentry);
247 dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry);
251 const 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,