fs/ceph/export.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/ceph/ceph_debug.h>
   3
   4 #include <linux/exportfs.h>
   5 #include <linux/slab.h>
   6 #include <asm/unaligned.h>
   7
   8 #include "super.h"
   9 #include "mds_client.h"
  10
  11 /*
  12  * Basic fh
  13  */
  14 struct ceph_nfs_fh {
  15         u64 ino;
  16 } __attribute__ ((packed));
  17
  18 /*
  19  * Larger fh that includes parent ino.
  20  */
  21 struct ceph_nfs_confh {
  22         u64 ino, parent_ino;
  23 } __attribute__ ((packed));
  24
  25 static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
  26                           struct inode *parent_inode)
  27 {
  28         int type;
  29         struct ceph_nfs_fh *fh = (void *)rawfh;
  30         struct ceph_nfs_confh *cfh = (void *)rawfh;
  31         int connected_handle_length = sizeof(*cfh)/4;
  32         int handle_length = sizeof(*fh)/4;
  33
  34         /* don't re-export snaps */
  35         if (ceph_snap(inode) != CEPH_NOSNAP)
  36                 return -EINVAL;
  37
  38         if (parent_inode && (*max_len < connected_handle_length)) {
  39                 *max_len = connected_handle_length;
  40                 return FILEID_INVALID;
  41         } else if (*max_len < handle_length) {
  42                 *max_len = handle_length;
  43                 return FILEID_INVALID;
  44         }
  45
  46         if (parent_inode) {
  47                 dout("encode_fh %llx with parent %llx\n",
  48                      ceph_ino(inode), ceph_ino(parent_inode));
  49                 cfh->ino = ceph_ino(inode);
  50                 cfh->parent_ino = ceph_ino(parent_inode);
  51                 *max_len = connected_handle_length;
  52                 type = FILEID_INO32_GEN_PARENT;
  53         } else {
  54                 dout("encode_fh %llx\n", ceph_ino(inode));
  55                 fh->ino = ceph_ino(inode);
  56                 *max_len = handle_length;
  57                 type = FILEID_INO32_GEN;
  58         }
  59         return type;
  60 }
  61
  62 static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
  63 {
  64         struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
  65         struct inode *inode;
  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                 int mask;
  75
  76                 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
  77                                                USE_ANY_MDS);
  78                 if (IS_ERR(req))
  79                         return ERR_CAST(req);
  80
  81                 mask = CEPH_STAT_CAP_INODE;
  82                 if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
  83                         mask |= CEPH_CAP_XATTR_SHARED;
  84                 req->r_args.getattr.mask = cpu_to_le32(mask);
  85
  86                 req->r_ino1 = vino;
  87                 req->r_num_caps = 1;
  88                 err = ceph_mdsc_do_request(mdsc, NULL, req);
  89                 inode = req->r_target_inode;
  90                 if (inode)
  91                         ihold(inode);
  92                 ceph_mdsc_put_request(req);
  93                 if (!inode)
  94                         return ERR_PTR(-ESTALE);
  95                 if (inode->i_nlink == 0) {
  96                         iput(inode);
  97                         return ERR_PTR(-ESTALE);
  98                 }
  99         }
 100
 101         return d_obtain_alias(inode);
 102 }
 103
 104 /*
 105  * convert regular fh to dentry
 106  */
 107 static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
 108                                         struct fid *fid,
 109                                         int fh_len, int fh_type)
 110 {
 111         struct ceph_nfs_fh *fh = (void *)fid->raw;
 112
 113         if (fh_type != FILEID_INO32_GEN  &&
 114             fh_type != FILEID_INO32_GEN_PARENT)
 115                 return NULL;
 116         if (fh_len < sizeof(*fh) / 4)
 117                 return NULL;
 118
 119         dout("fh_to_dentry %llx\n", fh->ino);
 120         return __fh_to_dentry(sb, fh->ino);
 121 }
 122
 123 static struct dentry *__get_parent(struct super_block *sb,
 124                                    struct dentry *child, u64 ino)
 125 {
 126         struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
 127         struct ceph_mds_request *req;
 128         struct inode *inode;
 129         int mask;
 130         int err;
 131
 132         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPPARENT,
 133                                        USE_ANY_MDS);
 134         if (IS_ERR(req))
 135                 return ERR_CAST(req);
 136
 137         if (child) {
 138                 req->r_inode = d_inode(child);
 139                 ihold(d_inode(child));
 140         } else {
 141                 req->r_ino1 = (struct ceph_vino) {
 142                         .ino = ino,
 143                         .snap = CEPH_NOSNAP,
 144                 };
 145         }
 146
 147         mask = CEPH_STAT_CAP_INODE;
 148         if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
 149                 mask |= CEPH_CAP_XATTR_SHARED;
 150         req->r_args.getattr.mask = cpu_to_le32(mask);
 151
 152         req->r_num_caps = 1;
 153         err = ceph_mdsc_do_request(mdsc, NULL, req);
 154         inode = req->r_target_inode;
 155         if (inode)
 156                 ihold(inode);
 157         ceph_mdsc_put_request(req);
 158         if (!inode)
 159                 return ERR_PTR(-ENOENT);
 160
 161         return d_obtain_alias(inode);
 162 }
 163
 164 static struct dentry *ceph_get_parent(struct dentry *child)
 165 {
 166         /* don't re-export snaps */
 167         if (ceph_snap(d_inode(child)) != CEPH_NOSNAP)
 168                 return ERR_PTR(-EINVAL);
 169
 170         dout("get_parent %p ino %llx.%llx\n",
 171              child, ceph_vinop(d_inode(child)));
 172         return __get_parent(child->d_sb, child, 0);
 173 }
 174
 175 /*
 176  * convert regular fh to parent
 177  */
 178 static struct dentry *ceph_fh_to_parent(struct super_block *sb,
 179                                         struct fid *fid,
 180                                         int fh_len, int fh_type)
 181 {
 182         struct ceph_nfs_confh *cfh = (void *)fid->raw;
 183         struct dentry *dentry;
 184
 185         if (fh_type != FILEID_INO32_GEN_PARENT)
 186                 return NULL;
 187         if (fh_len < sizeof(*cfh) / 4)
 188                 return NULL;
 189
 190         dout("fh_to_parent %llx\n", cfh->parent_ino);
 191         dentry = __get_parent(sb, NULL, cfh->ino);
 192         if (unlikely(dentry == ERR_PTR(-ENOENT)))
 193                 dentry = __fh_to_dentry(sb, cfh->parent_ino);
 194         return dentry;
 195 }
 196
 197 static int ceph_get_name(struct dentry *parent, char *name,
 198                          struct dentry *child)
 199 {
 200         struct ceph_mds_client *mdsc;
 201         struct ceph_mds_request *req;
 202         int err;
 203
 204         mdsc = ceph_inode_to_client(d_inode(child))->mdsc;
 205         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
 206                                        USE_ANY_MDS);
 207         if (IS_ERR(req))
 208                 return PTR_ERR(req);
 209
 210         inode_lock(d_inode(parent));
 211
 212         req->r_inode = d_inode(child);
 213         ihold(d_inode(child));
 214         req->r_ino2 = ceph_vino(d_inode(parent));
 215         req->r_parent = d_inode(parent);
 216         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 217         req->r_num_caps = 2;
 218         err = ceph_mdsc_do_request(mdsc, NULL, req);
 219
 220         inode_unlock(d_inode(parent));
 221
 222         if (!err) {
 223                 struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
 224                 memcpy(name, rinfo->dname, rinfo->dname_len);
 225                 name[rinfo->dname_len] = 0;
 226                 dout("get_name %p ino %llx.%llx name %s\n",
 227                      child, ceph_vinop(d_inode(child)), name);
 228         } else {
 229                 dout("get_name %p ino %llx.%llx err %d\n",
 230                      child, ceph_vinop(d_inode(child)), err);
 231         }
 232
 233         ceph_mdsc_put_request(req);
 234         return err;
 235 }
 236
 237 const struct export_operations ceph_export_ops = {
 238         .encode_fh = ceph_encode_fh,
 239         .fh_to_dentry = ceph_fh_to_dentry,
 240         .fh_to_parent = ceph_fh_to_parent,
 241         .get_parent = ceph_get_parent,
 242         .get_name = ceph_get_name,
 243 };