1 #include "ceph_debug.h"
3 #include <linux/exportfs.h>
4 #include <linux/slab.h>
5 #include <asm/unaligned.h>
12 * NFS re-export of a ceph mount is, at present, only semireliable.
13 * The basic issue is that the Ceph architectures doesn't lend itself
14 * well to generating filehandles that will remain valid forever.
16 * So, we do our best. If you're lucky, your inode will be in the
17 * client's cache. If it's not, and you have a connectable fh, then
18 * the MDS server may be able to find it for you. Otherwise, you get
21 * There are ways to this more reliable, but in the non-connectable fh
22 * case, we won't every work perfectly, and in the connectable case,
23 * some changes are needed on the MDS side to work better.
31 } __attribute__ ((packed));
34 * Larger 'connectable' fh that includes parent ino and name hash.
35 * Use this whenever possible, as it works more reliably.
37 struct ceph_nfs_confh {
40 } __attribute__ ((packed));
42 static int ceph_encode_fh(struct dentry *dentry, u32 *rawfh, int *max_len,
45 struct ceph_nfs_fh *fh = (void *)rawfh;
46 struct ceph_nfs_confh *cfh = (void *)rawfh;
47 struct dentry *parent = dentry->d_parent;
48 struct inode *inode = dentry->d_inode;
51 /* don't re-export snaps */
52 if (ceph_snap(inode) != CEPH_NOSNAP)
55 if (*max_len >= sizeof(*cfh)) {
56 dout("encode_fh %p connectable\n", dentry);
57 cfh->ino = ceph_ino(dentry->d_inode);
58 cfh->parent_ino = ceph_ino(parent->d_inode);
59 cfh->parent_name_hash = parent->d_name.hash;
60 *max_len = sizeof(*cfh);
62 } else if (*max_len > sizeof(*fh)) {
65 dout("encode_fh %p\n", dentry);
66 fh->ino = ceph_ino(dentry->d_inode);
67 *max_len = sizeof(*fh);
76 * convert regular fh to dentry
78 * FIXME: we should try harder by querying the mds for the ino.
80 static struct dentry *__fh_to_dentry(struct super_block *sb,
81 struct ceph_nfs_fh *fh)
84 struct dentry *dentry;
85 struct ceph_vino vino;
88 dout("__fh_to_dentry %llx\n", fh->ino);
90 vino.snap = CEPH_NOSNAP;
91 inode = ceph_find_inode(sb, vino);
93 return ERR_PTR(-ESTALE);
95 dentry = d_obtain_alias(inode);
97 pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n",
100 return ERR_PTR(-ENOMEM);
102 err = ceph_init_dentry(dentry);
108 dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry);
113 * convert connectable fh to dentry
115 static struct dentry *__cfh_to_dentry(struct super_block *sb,
116 struct ceph_nfs_confh *cfh)
118 struct ceph_mds_client *mdsc = &ceph_client(sb)->mdsc;
120 struct dentry *dentry;
121 struct ceph_vino vino;
124 dout("__cfh_to_dentry %llx (%llx/%x)\n",
125 cfh->ino, cfh->parent_ino, cfh->parent_name_hash);
128 vino.snap = CEPH_NOSNAP;
129 inode = ceph_find_inode(sb, vino);
131 struct ceph_mds_request *req;
133 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH,
136 return ERR_PTR(PTR_ERR(req));
139 req->r_ino2.ino = cfh->parent_ino;
140 req->r_ino2.snap = CEPH_NOSNAP;
141 req->r_path2 = kmalloc(16, GFP_NOFS);
142 snprintf(req->r_path2, 16, "%d", cfh->parent_name_hash);
144 err = ceph_mdsc_do_request(mdsc, NULL, req);
145 ceph_mdsc_put_request(req);
146 inode = ceph_find_inode(sb, vino);
148 return ERR_PTR(err ? err : -ESTALE);
151 dentry = d_obtain_alias(inode);
153 pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n",
156 return ERR_PTR(-ENOMEM);
158 err = ceph_init_dentry(dentry);
163 dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry);
167 static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid,
168 int fh_len, int fh_type)
171 return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw);
173 return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw);
177 * get parent, if possible.
179 * FIXME: we could do better by querying the mds to discover the
182 static struct dentry *ceph_fh_to_parent(struct super_block *sb,
184 int fh_len, int fh_type)
186 struct ceph_nfs_confh *cfh = (void *)fid->raw;
187 struct ceph_vino vino;
189 struct dentry *dentry;
193 return ERR_PTR(-ESTALE);
195 pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino,
196 cfh->parent_name_hash);
199 vino.snap = CEPH_NOSNAP;
200 inode = ceph_find_inode(sb, vino);
202 return ERR_PTR(-ESTALE);
204 dentry = d_obtain_alias(inode);
206 pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n",
209 return ERR_PTR(-ENOMEM);
211 err = ceph_init_dentry(dentry);
216 dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry);
220 const struct export_operations ceph_export_ops = {
221 .encode_fh = ceph_encode_fh,
222 .fh_to_dentry = ceph_fh_to_dentry,
223 .fh_to_parent = ceph_fh_to_parent,