Sage Weil | a8e63b7 | 2009-10-06 11:31:13 -0700 | [diff] [blame] | 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 | }; |