Commit | Line | Data |
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a8e63b7d SW |
1 | #include "ceph_debug.h" |
2 | ||
3 | #include <linux/exportfs.h> | |
4 | #include <asm/unaligned.h> | |
5 | ||
6 | #include "super.h" | |
7 | ||
8 | /* | |
9 | * NFS export support | |
10 | * | |
11 | * NFS re-export of a ceph mount is, at present, only semireliable. | |
12 | * The basic issue is that the Ceph architectures doesn't lend itself | |
13 | * well to generating filehandles that will remain valid forever. | |
14 | * | |
15 | * So, we do our best. If you're lucky, your inode will be in the | |
16 | * client's cache. If it's not, and you have a connectable fh, then | |
17 | * the MDS server may be able to find it for you. Otherwise, you get | |
18 | * ESTALE. | |
19 | * | |
20 | * There are ways to this more reliable, but in the non-connectable fh | |
21 | * case, we won't every work perfectly, and in the connectable case, | |
22 | * some changes are needed on the MDS side to work better. | |
23 | */ | |
24 | ||
25 | /* | |
26 | * Basic fh | |
27 | */ | |
28 | struct ceph_nfs_fh { | |
29 | u64 ino; | |
30 | } __attribute__ ((packed)); | |
31 | ||
32 | /* | |
33 | * Larger 'connectable' fh that includes parent ino and name hash. | |
34 | * Use this whenever possible, as it works more reliably. | |
35 | */ | |
36 | struct ceph_nfs_confh { | |
37 | u64 ino, parent_ino; | |
38 | u32 parent_name_hash; | |
39 | } __attribute__ ((packed)); | |
40 | ||
41 | static int ceph_encode_fh(struct dentry *dentry, u32 *rawfh, int *max_len, | |
42 | int connectable) | |
43 | { | |
44 | struct ceph_nfs_fh *fh = (void *)rawfh; | |
45 | struct ceph_nfs_confh *cfh = (void *)rawfh; | |
46 | struct dentry *parent = dentry->d_parent; | |
47 | struct inode *inode = dentry->d_inode; | |
48 | int type; | |
49 | ||
50 | /* don't re-export snaps */ | |
51 | if (ceph_snap(inode) != CEPH_NOSNAP) | |
52 | return -EINVAL; | |
53 | ||
54 | if (*max_len >= sizeof(*cfh)) { | |
55 | dout("encode_fh %p connectable\n", dentry); | |
56 | cfh->ino = ceph_ino(dentry->d_inode); | |
57 | cfh->parent_ino = ceph_ino(parent->d_inode); | |
58 | cfh->parent_name_hash = parent->d_name.hash; | |
59 | *max_len = sizeof(*cfh); | |
60 | type = 2; | |
61 | } else if (*max_len > sizeof(*fh)) { | |
62 | if (connectable) | |
63 | return -ENOSPC; | |
64 | dout("encode_fh %p\n", dentry); | |
65 | fh->ino = ceph_ino(dentry->d_inode); | |
66 | *max_len = sizeof(*fh); | |
67 | type = 1; | |
68 | } else { | |
69 | return -ENOSPC; | |
70 | } | |
71 | return type; | |
72 | } | |
73 | ||
74 | /* | |
75 | * convert regular fh to dentry | |
76 | * | |
77 | * FIXME: we should try harder by querying the mds for the ino. | |
78 | */ | |
79 | static struct dentry *__fh_to_dentry(struct super_block *sb, | |
80 | struct ceph_nfs_fh *fh) | |
81 | { | |
82 | struct inode *inode; | |
83 | struct dentry *dentry; | |
84 | struct ceph_vino vino; | |
85 | int err; | |
86 | ||
87 | dout("__fh_to_dentry %llx\n", fh->ino); | |
88 | vino.ino = fh->ino; | |
89 | vino.snap = CEPH_NOSNAP; | |
90 | inode = ceph_find_inode(sb, vino); | |
91 | if (!inode) | |
92 | return ERR_PTR(-ESTALE); | |
93 | ||
94 | dentry = d_obtain_alias(inode); | |
95 | if (!dentry) { | |
96 | pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n", | |
97 | fh->ino, inode); | |
98 | iput(inode); | |
99 | return ERR_PTR(-ENOMEM); | |
100 | } | |
101 | err = ceph_init_dentry(dentry); | |
102 | ||
103 | if (err < 0) { | |
104 | iput(inode); | |
105 | return ERR_PTR(err); | |
106 | } | |
107 | dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry); | |
108 | return dentry; | |
109 | } | |
110 | ||
111 | /* | |
112 | * convert connectable fh to dentry | |
113 | */ | |
114 | static struct dentry *__cfh_to_dentry(struct super_block *sb, | |
115 | struct ceph_nfs_confh *cfh) | |
116 | { | |
117 | struct ceph_mds_client *mdsc = &ceph_client(sb)->mdsc; | |
118 | struct inode *inode; | |
119 | struct dentry *dentry; | |
120 | struct ceph_vino vino; | |
121 | int err; | |
122 | ||
123 | dout("__cfh_to_dentry %llx (%llx/%x)\n", | |
124 | cfh->ino, cfh->parent_ino, cfh->parent_name_hash); | |
125 | ||
126 | vino.ino = cfh->ino; | |
127 | vino.snap = CEPH_NOSNAP; | |
128 | inode = ceph_find_inode(sb, vino); | |
129 | if (!inode) { | |
130 | struct ceph_mds_request *req; | |
131 | ||
132 | req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH, | |
133 | USE_ANY_MDS); | |
134 | if (IS_ERR(req)) | |
135 | return ERR_PTR(PTR_ERR(req)); | |
136 | ||
137 | req->r_ino1 = vino; | |
138 | req->r_ino2.ino = cfh->parent_ino; | |
139 | req->r_ino2.snap = CEPH_NOSNAP; | |
140 | req->r_path2 = kmalloc(16, GFP_NOFS); | |
141 | snprintf(req->r_path2, 16, "%d", cfh->parent_name_hash); | |
142 | req->r_num_caps = 1; | |
143 | err = ceph_mdsc_do_request(mdsc, NULL, req); | |
144 | ceph_mdsc_put_request(req); | |
145 | inode = ceph_find_inode(sb, vino); | |
146 | if (!inode) | |
147 | return ERR_PTR(err ? err : -ESTALE); | |
148 | } | |
149 | ||
150 | dentry = d_obtain_alias(inode); | |
151 | if (!dentry) { | |
152 | pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n", | |
153 | cfh->ino, inode); | |
154 | iput(inode); | |
155 | return ERR_PTR(-ENOMEM); | |
156 | } | |
157 | err = ceph_init_dentry(dentry); | |
158 | if (err < 0) { | |
159 | iput(inode); | |
160 | return ERR_PTR(err); | |
161 | } | |
162 | dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry); | |
163 | return dentry; | |
164 | } | |
165 | ||
166 | static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
167 | int fh_len, int fh_type) | |
168 | { | |
169 | if (fh_type == 1) | |
170 | return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw); | |
171 | else | |
172 | return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw); | |
173 | } | |
174 | ||
175 | /* | |
176 | * get parent, if possible. | |
177 | * | |
178 | * FIXME: we could do better by querying the mds to discover the | |
179 | * parent. | |
180 | */ | |
181 | static struct dentry *ceph_fh_to_parent(struct super_block *sb, | |
182 | struct fid *fid, | |
183 | int fh_len, int fh_type) | |
184 | { | |
185 | struct ceph_nfs_confh *cfh = (void *)fid->raw; | |
186 | struct ceph_vino vino; | |
187 | struct inode *inode; | |
188 | struct dentry *dentry; | |
189 | int err; | |
190 | ||
191 | if (fh_type == 1) | |
192 | return ERR_PTR(-ESTALE); | |
193 | ||
194 | pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino, | |
195 | cfh->parent_name_hash); | |
196 | ||
197 | vino.ino = cfh->ino; | |
198 | vino.snap = CEPH_NOSNAP; | |
199 | inode = ceph_find_inode(sb, vino); | |
200 | if (!inode) | |
201 | return ERR_PTR(-ESTALE); | |
202 | ||
203 | dentry = d_obtain_alias(inode); | |
204 | if (!dentry) { | |
205 | pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n", | |
206 | cfh->ino, inode); | |
207 | iput(inode); | |
208 | return ERR_PTR(-ENOMEM); | |
209 | } | |
210 | err = ceph_init_dentry(dentry); | |
211 | if (err < 0) { | |
212 | iput(inode); | |
213 | return ERR_PTR(err); | |
214 | } | |
215 | dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry); | |
216 | return dentry; | |
217 | } | |
218 | ||
219 | const struct export_operations ceph_export_ops = { | |
220 | .encode_fh = ceph_encode_fh, | |
221 | .fh_to_dentry = ceph_fh_to_dentry, | |
222 | .fh_to_parent = ceph_fh_to_parent, | |
223 | }; |