fs/ceph/export.c

   1 #include <linux/ceph/ceph_debug.h>
   2
   3 #include <linux/exportfs.h>
   4 #include <linux/slab.h>
   5 #include <asm/unaligned.h>
   6
   7 #include "super.h"
   8 #include "mds_client.h"
   9
  10 /*
  11  * Basic fh
  12  */
  13 struct ceph_nfs_fh {
  14         u64 ino;
  15 } __attribute__ ((packed));
  16
  17 /*
  18  * Larger fh that includes parent ino.
  19  */
  20 struct ceph_nfs_confh {
  21         u64 ino, parent_ino;
  22 } __attribute__ ((packed));
  23
  24 static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
  25                           struct inode *parent_inode)
  26 {
  27         int type;
  28         struct ceph_nfs_fh *fh = (void *)rawfh;
  29         struct ceph_nfs_confh *cfh = (void *)rawfh;
  30         int connected_handle_length = sizeof(*cfh)/4;
  31         int handle_length = sizeof(*fh)/4;
  32
  33         /* don't re-export snaps */
  34         if (ceph_snap(inode) != CEPH_NOSNAP)
  35                 return -EINVAL;
  36
  37         if (parent_inode && (*max_len < connected_handle_length)) {
  38                 *max_len = connected_handle_length;
  39                 return FILEID_INVALID;
  40         } else if (*max_len < handle_length) {
  41                 *max_len = handle_length;
  42                 return FILEID_INVALID;
  43         }
  44
  45         if (parent_inode) {
  46                 dout("encode_fh %llx with parent %llx\n",
  47                      ceph_ino(inode), ceph_ino(parent_inode));
  48                 cfh->ino = ceph_ino(inode);
  49                 cfh->parent_ino = ceph_ino(parent_inode);
  50                 *max_len = connected_handle_length;
  51                 type = FILEID_INO32_GEN_PARENT;
  52         } else {
  53                 dout("encode_fh %llx\n", ceph_ino(inode));
  54                 fh->ino = ceph_ino(inode);
  55                 *max_len = handle_length;
  56                 type = FILEID_INO32_GEN;
  57         }
  58         return type;
  59 }
  60
  61 static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
  62 {
  63         struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
  64         struct inode *inode;
  65         struct dentry *dentry;
  66         struct ceph_vino vino;
  67         int err;
  68
  69         vino.ino = ino;
  70         vino.snap = CEPH_NOSNAP;
  71         inode = ceph_find_inode(sb, vino);
  72         if (!inode) {
  73                 struct ceph_mds_request *req;
  74
  75                 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
  76                                                USE_ANY_MDS);
  77                 if (IS_ERR(req))
  78                         return ERR_CAST(req);
  79
  80                 req->r_ino1 = vino;
  81                 req->r_num_caps = 1;
  82                 err = ceph_mdsc_do_request(mdsc, NULL, req);
  83                 inode = req->r_target_inode;
  84                 if (inode)
  85                         ihold(inode);
  86                 ceph_mdsc_put_request(req);
  87                 if (!inode)
  88                         return ERR_PTR(-ESTALE);
  89         }
  90
  91         dentry = d_obtain_alias(inode);
  92         if (IS_ERR(dentry)) {
  93                 iput(inode);
  94                 return dentry;
  95         }
  96         err = ceph_init_dentry(dentry);
  97         if (err < 0) {
  98                 dput(dentry);
  99                 return ERR_PTR(err);
 100         }
 101         dout("__fh_to_dentry %llx %p dentry %p\n", ino, inode, dentry);
 102         return dentry;
 103 }
 104
 105 /*
 106  * convert regular fh to dentry
 107  */
 108 static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
 109                                         struct fid *fid,
 110                                         int fh_len, int fh_type)
 111 {
 112         struct ceph_nfs_fh *fh = (void *)fid->raw;
 113
 114         if (fh_type != FILEID_INO32_GEN  &&
 115             fh_type != FILEID_INO32_GEN_PARENT)
 116                 return NULL;
 117         if (fh_len < sizeof(*fh) / 4)
 118                 return NULL;
 119
 120         dout("fh_to_dentry %llx\n", fh->ino);
 121         return __fh_to_dentry(sb, fh->ino);
 122 }
 123
 124 static struct dentry *__get_parent(struct super_block *sb,
 125                                    struct dentry *child, u64 ino)
 126 {
 127         struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
 128         struct ceph_mds_request *req;
 129         struct inode *inode;
 130         struct dentry *dentry;
 131         int err;
 132
 133         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPPARENT,
 134                                        USE_ANY_MDS);
 135         if (IS_ERR(req))
 136                 return ERR_CAST(req);
 137
 138         if (child) {
 139                 req->r_inode = d_inode(child);
 140                 ihold(d_inode(child));
 141         } else {
 142                 req->r_ino1 = (struct ceph_vino) {
 143                         .ino = ino,
 144                         .snap = CEPH_NOSNAP,
 145                 };
 146         }
 147         req->r_num_caps = 1;
 148         err = ceph_mdsc_do_request(mdsc, NULL, req);
 149         inode = req->r_target_inode;
 150         if (inode)
 151                 ihold(inode);
 152         ceph_mdsc_put_request(req);
 153         if (!inode)
 154                 return ERR_PTR(-ENOENT);
 155
 156         dentry = d_obtain_alias(inode);
 157         if (IS_ERR(dentry)) {
 158                 iput(inode);
 159                 return dentry;
 160         }
 161         err = ceph_init_dentry(dentry);
 162         if (err < 0) {
 163                 dput(dentry);
 164                 return ERR_PTR(err);
 165         }
 166         dout("__get_parent ino %llx parent %p ino %llx.%llx\n",
 167              child ? ceph_ino(d_inode(child)) : ino,
 168              dentry, ceph_vinop(inode));
 169         return dentry;
 170 }
 171
 172 static struct dentry *ceph_get_parent(struct dentry *child)
 173 {
 174         /* don't re-export snaps */
 175         if (ceph_snap(d_inode(child)) != CEPH_NOSNAP)
 176                 return ERR_PTR(-EINVAL);
 177
 178         dout("get_parent %p ino %llx.%llx\n",
 179              child, ceph_vinop(d_inode(child)));
 180         return __get_parent(child->d_sb, child, 0);
 181 }
 182
 183 /*
 184  * convert regular fh to parent
 185  */
 186 static struct dentry *ceph_fh_to_parent(struct super_block *sb,
 187                                         struct fid *fid,
 188                                         int fh_len, int fh_type)
 189 {
 190         struct ceph_nfs_confh *cfh = (void *)fid->raw;
 191         struct dentry *dentry;
 192
 193         if (fh_type != FILEID_INO32_GEN_PARENT)
 194                 return NULL;
 195         if (fh_len < sizeof(*cfh) / 4)
 196                 return NULL;
 197
 198         dout("fh_to_parent %llx\n", cfh->parent_ino);
 199         dentry = __get_parent(sb, NULL, cfh->ino);
 200         if (IS_ERR(dentry) && PTR_ERR(dentry) == -ENOENT)
 201                 dentry = __fh_to_dentry(sb, cfh->parent_ino);
 202         return dentry;
 203 }
 204
 205 static int ceph_get_name(struct dentry *parent, char *name,
 206                          struct dentry *child)
 207 {
 208         struct ceph_mds_client *mdsc;
 209         struct ceph_mds_request *req;
 210         int err;
 211
 212         mdsc = ceph_inode_to_client(d_inode(child))->mdsc;
 213         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
 214                                        USE_ANY_MDS);
 215         if (IS_ERR(req))
 216                 return PTR_ERR(req);
 217
 218         mutex_lock(&d_inode(parent)->i_mutex);
 219
 220         req->r_inode = d_inode(child);
 221         ihold(d_inode(child));
 222         req->r_ino2 = ceph_vino(d_inode(parent));
 223         req->r_locked_dir = d_inode(parent);
 224         req->r_num_caps = 2;
 225         err = ceph_mdsc_do_request(mdsc, NULL, req);
 226
 227         mutex_unlock(&d_inode(parent)->i_mutex);
 228
 229         if (!err) {
 230                 struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
 231                 memcpy(name, rinfo->dname, rinfo->dname_len);
 232                 name[rinfo->dname_len] = 0;
 233                 dout("get_name %p ino %llx.%llx name %s\n",
 234                      child, ceph_vinop(d_inode(child)), name);
 235         } else {
 236                 dout("get_name %p ino %llx.%llx err %d\n",
 237                      child, ceph_vinop(d_inode(child)), err);
 238         }
 239
 240         ceph_mdsc_put_request(req);
 241         return err;
 242 }
 243
 244 const struct export_operations ceph_export_ops = {
 245         .encode_fh = ceph_encode_fh,
 246         .fh_to_dentry = ceph_fh_to_dentry,
 247         .fh_to_parent = ceph_fh_to_parent,
 248         .get_parent = ceph_get_parent,
 249         .get_name = ceph_get_name,
 250 };