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 ceph_vino vino;
  66         int err;
  67
  68         vino.ino = ino;
  69         vino.snap = CEPH_NOSNAP;
  70         inode = ceph_find_inode(sb, vino);
  71         if (!inode) {
  72                 struct ceph_mds_request *req;
  73                 int mask;
  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                 mask = CEPH_STAT_CAP_INODE;
  81                 if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
  82                         mask |= CEPH_CAP_XATTR_SHARED;
  83                 req->r_args.getattr.mask = cpu_to_le32(mask);
  84
  85                 req->r_ino1 = vino;
  86                 req->r_num_caps = 1;
  87                 err = ceph_mdsc_do_request(mdsc, NULL, req);
  88                 inode = req->r_target_inode;
  89                 if (inode)
  90                         ihold(inode);
  91                 ceph_mdsc_put_request(req);
  92                 if (!inode)
  93                         return ERR_PTR(-ESTALE);
  94                 if (inode->i_nlink == 0) {
  95                         iput(inode);
  96                         return ERR_PTR(-ESTALE);
  97                 }
  98         }
  99
 100         return d_obtain_alias(inode);
 101 }
 102
 103 /*
 104  * convert regular fh to dentry
 105  */
 106 static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
 107                                         struct fid *fid,
 108                                         int fh_len, int fh_type)
 109 {
 110         struct ceph_nfs_fh *fh = (void *)fid->raw;
 111
 112         if (fh_type != FILEID_INO32_GEN  &&
 113             fh_type != FILEID_INO32_GEN_PARENT)
 114                 return NULL;
 115         if (fh_len < sizeof(*fh) / 4)
 116                 return NULL;
 117
 118         dout("fh_to_dentry %llx\n", fh->ino);
 119         return __fh_to_dentry(sb, fh->ino);
 120 }
 121
 122 static struct dentry *__get_parent(struct super_block *sb,
 123                                    struct dentry *child, u64 ino)
 124 {
 125         struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
 126         struct ceph_mds_request *req;
 127         struct inode *inode;
 128         int mask;
 129         int err;
 130
 131         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPPARENT,
 132                                        USE_ANY_MDS);
 133         if (IS_ERR(req))
 134                 return ERR_CAST(req);
 135
 136         if (child) {
 137                 req->r_inode = d_inode(child);
 138                 ihold(d_inode(child));
 139         } else {
 140                 req->r_ino1 = (struct ceph_vino) {
 141                         .ino = ino,
 142                         .snap = CEPH_NOSNAP,
 143                 };
 144         }
 145
 146         mask = CEPH_STAT_CAP_INODE;
 147         if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
 148                 mask |= CEPH_CAP_XATTR_SHARED;
 149         req->r_args.getattr.mask = cpu_to_le32(mask);
 150
 151         req->r_num_caps = 1;
 152         err = ceph_mdsc_do_request(mdsc, NULL, req);
 153         inode = req->r_target_inode;
 154         if (inode)
 155                 ihold(inode);
 156         ceph_mdsc_put_request(req);
 157         if (!inode)
 158                 return ERR_PTR(-ENOENT);
 159
 160         return d_obtain_alias(inode);
 161 }
 162
 163 static struct dentry *ceph_get_parent(struct dentry *child)
 164 {
 165         /* don't re-export snaps */
 166         if (ceph_snap(d_inode(child)) != CEPH_NOSNAP)
 167                 return ERR_PTR(-EINVAL);
 168
 169         dout("get_parent %p ino %llx.%llx\n",
 170              child, ceph_vinop(d_inode(child)));
 171         return __get_parent(child->d_sb, child, 0);
 172 }
 173
 174 /*
 175  * convert regular fh to parent
 176  */
 177 static struct dentry *ceph_fh_to_parent(struct super_block *sb,
 178                                         struct fid *fid,
 179                                         int fh_len, int fh_type)
 180 {
 181         struct ceph_nfs_confh *cfh = (void *)fid->raw;
 182         struct dentry *dentry;
 183
 184         if (fh_type != FILEID_INO32_GEN_PARENT)
 185                 return NULL;
 186         if (fh_len < sizeof(*cfh) / 4)
 187                 return NULL;
 188
 189         dout("fh_to_parent %llx\n", cfh->parent_ino);
 190         dentry = __get_parent(sb, NULL, cfh->ino);
 191         if (unlikely(dentry == ERR_PTR(-ENOENT)))
 192                 dentry = __fh_to_dentry(sb, cfh->parent_ino);
 193         return dentry;
 194 }
 195
 196 static int ceph_get_name(struct dentry *parent, char *name,
 197                          struct dentry *child)
 198 {
 199         struct ceph_mds_client *mdsc;
 200         struct ceph_mds_request *req;
 201         int err;
 202
 203         mdsc = ceph_inode_to_client(d_inode(child))->mdsc;
 204         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
 205                                        USE_ANY_MDS);
 206         if (IS_ERR(req))
 207                 return PTR_ERR(req);
 208
 209         inode_lock(d_inode(parent));
 210
 211         req->r_inode = d_inode(child);
 212         ihold(d_inode(child));
 213         req->r_ino2 = ceph_vino(d_inode(parent));
 214         req->r_parent = d_inode(parent);
 215         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 216         req->r_num_caps = 2;
 217         err = ceph_mdsc_do_request(mdsc, NULL, req);
 218
 219         inode_unlock(d_inode(parent));
 220
 221         if (!err) {
 222                 struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
 223                 memcpy(name, rinfo->dname, rinfo->dname_len);
 224                 name[rinfo->dname_len] = 0;
 225                 dout("get_name %p ino %llx.%llx name %s\n",
 226                      child, ceph_vinop(d_inode(child)), name);
 227         } else {
 228                 dout("get_name %p ino %llx.%llx err %d\n",
 229                      child, ceph_vinop(d_inode(child)), err);
 230         }
 231
 232         ceph_mdsc_put_request(req);
 233         return err;
 234 }
 235
 236 const struct export_operations ceph_export_ops = {
 237         .encode_fh = ceph_encode_fh,
 238         .fh_to_dentry = ceph_fh_to_dentry,
 239         .fh_to_parent = ceph_fh_to_parent,
 240         .get_parent = ceph_get_parent,
 241         .get_name = ceph_get_name,
 242 };