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 = dentry->d_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 if (*max_len >= connected_handle_length) {
59 dout("encode_fh %p connectable\n", dentry);
60 cfh->ino = ceph_ino(dentry->d_inode);
61 cfh->parent_ino = ceph_ino(parent->d_inode);
62 cfh->parent_name_hash = ceph_dentry_hash(parent);
63 *max_len = connected_handle_length;
65 } else if (*max_len >= handle_length) {
67 *max_len = connected_handle_length;
70 dout("encode_fh %p\n", dentry);
71 fh->ino = ceph_ino(dentry->d_inode);
72 *max_len = handle_length;
75 *max_len = handle_length;
82 * convert regular fh to dentry
84 * FIXME: we should try harder by querying the mds for the ino.
86 static struct dentry *__fh_to_dentry(struct super_block *sb,
87 struct ceph_nfs_fh *fh)
89 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
91 struct dentry *dentry;
92 struct ceph_vino vino;
95 dout("__fh_to_dentry %llx\n", fh->ino);
97 vino.snap = CEPH_NOSNAP;
98 inode = ceph_find_inode(sb, vino);
100 struct ceph_mds_request *req;
102 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
105 return ERR_CAST(req);
109 err = ceph_mdsc_do_request(mdsc, NULL, req);
110 inode = req->r_target_inode;
113 ceph_mdsc_put_request(req);
115 return ERR_PTR(-ESTALE);
118 dentry = d_obtain_alias(inode);
119 if (IS_ERR(dentry)) {
120 pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n",
125 err = ceph_init_dentry(dentry);
131 dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry);
136 * convert connectable fh to dentry
138 static struct dentry *__cfh_to_dentry(struct super_block *sb,
139 struct ceph_nfs_confh *cfh)
141 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
143 struct dentry *dentry;
144 struct ceph_vino vino;
147 dout("__cfh_to_dentry %llx (%llx/%x)\n",
148 cfh->ino, cfh->parent_ino, cfh->parent_name_hash);
151 vino.snap = CEPH_NOSNAP;
152 inode = ceph_find_inode(sb, vino);
154 struct ceph_mds_request *req;
156 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH,
159 return ERR_CAST(req);
162 req->r_ino2.ino = cfh->parent_ino;
163 req->r_ino2.snap = CEPH_NOSNAP;
164 req->r_path2 = kmalloc(16, GFP_NOFS);
165 snprintf(req->r_path2, 16, "%d", cfh->parent_name_hash);
167 err = ceph_mdsc_do_request(mdsc, NULL, req);
168 inode = req->r_target_inode;
171 ceph_mdsc_put_request(req);
173 return ERR_PTR(err ? err : -ESTALE);
176 dentry = d_obtain_alias(inode);
177 if (IS_ERR(dentry)) {
178 pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n",
183 err = ceph_init_dentry(dentry);
188 dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry);
192 static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid,
193 int fh_len, int fh_type)
196 return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw);
198 return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw);
202 * get parent, if possible.
204 * FIXME: we could do better by querying the mds to discover the
207 static struct dentry *ceph_fh_to_parent(struct super_block *sb,
209 int fh_len, int fh_type)
211 struct ceph_nfs_confh *cfh = (void *)fid->raw;
212 struct ceph_vino vino;
214 struct dentry *dentry;
218 return ERR_PTR(-ESTALE);
220 pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino,
221 cfh->parent_name_hash);
224 vino.snap = CEPH_NOSNAP;
225 inode = ceph_find_inode(sb, vino);
227 return ERR_PTR(-ESTALE);
229 dentry = d_obtain_alias(inode);
230 if (IS_ERR(dentry)) {
231 pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n",
236 err = ceph_init_dentry(dentry);
241 dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry);
245 const struct export_operations ceph_export_ops = {
246 .encode_fh = ceph_encode_fh,
247 .fh_to_dentry = ceph_fh_to_dentry,
248 .fh_to_parent = ceph_fh_to_parent,