| #include "ceph_debug.h" |
| |
| #include <linux/exportfs.h> |
| #include <linux/slab.h> |
| #include <asm/unaligned.h> |
| |
| #include "super.h" |
| |
| /* |
| * NFS export support |
| * |
| * NFS re-export of a ceph mount is, at present, only semireliable. |
| * The basic issue is that the Ceph architectures doesn't lend itself |
| * well to generating filehandles that will remain valid forever. |
| * |
| * So, we do our best. If you're lucky, your inode will be in the |
| * client's cache. If it's not, and you have a connectable fh, then |
| * the MDS server may be able to find it for you. Otherwise, you get |
| * ESTALE. |
| * |
| * There are ways to this more reliable, but in the non-connectable fh |
| * case, we won't every work perfectly, and in the connectable case, |
| * some changes are needed on the MDS side to work better. |
| */ |
| |
| /* |
| * Basic fh |
| */ |
| struct ceph_nfs_fh { |
| u64 ino; |
| } __attribute__ ((packed)); |
| |
| /* |
| * Larger 'connectable' fh that includes parent ino and name hash. |
| * Use this whenever possible, as it works more reliably. |
| */ |
| struct ceph_nfs_confh { |
| u64 ino, parent_ino; |
| u32 parent_name_hash; |
| } __attribute__ ((packed)); |
| |
| static int ceph_encode_fh(struct dentry *dentry, u32 *rawfh, int *max_len, |
| int connectable) |
| { |
| struct ceph_nfs_fh *fh = (void *)rawfh; |
| struct ceph_nfs_confh *cfh = (void *)rawfh; |
| struct dentry *parent = dentry->d_parent; |
| struct inode *inode = dentry->d_inode; |
| int type; |
| |
| /* don't re-export snaps */ |
| if (ceph_snap(inode) != CEPH_NOSNAP) |
| return -EINVAL; |
| |
| if (*max_len >= sizeof(*cfh)) { |
| dout("encode_fh %p connectable\n", dentry); |
| cfh->ino = ceph_ino(dentry->d_inode); |
| cfh->parent_ino = ceph_ino(parent->d_inode); |
| cfh->parent_name_hash = parent->d_name.hash; |
| *max_len = sizeof(*cfh); |
| type = 2; |
| } else if (*max_len > sizeof(*fh)) { |
| if (connectable) |
| return -ENOSPC; |
| dout("encode_fh %p\n", dentry); |
| fh->ino = ceph_ino(dentry->d_inode); |
| *max_len = sizeof(*fh); |
| type = 1; |
| } else { |
| return -ENOSPC; |
| } |
| return type; |
| } |
| |
| /* |
| * convert regular fh to dentry |
| * |
| * FIXME: we should try harder by querying the mds for the ino. |
| */ |
| static struct dentry *__fh_to_dentry(struct super_block *sb, |
| struct ceph_nfs_fh *fh) |
| { |
| struct inode *inode; |
| struct dentry *dentry; |
| struct ceph_vino vino; |
| int err; |
| |
| dout("__fh_to_dentry %llx\n", fh->ino); |
| vino.ino = fh->ino; |
| vino.snap = CEPH_NOSNAP; |
| inode = ceph_find_inode(sb, vino); |
| if (!inode) |
| return ERR_PTR(-ESTALE); |
| |
| dentry = d_obtain_alias(inode); |
| if (IS_ERR(dentry)) { |
| pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n", |
| fh->ino, inode); |
| iput(inode); |
| return dentry; |
| } |
| err = ceph_init_dentry(dentry); |
| |
| if (err < 0) { |
| iput(inode); |
| return ERR_PTR(err); |
| } |
| dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry); |
| return dentry; |
| } |
| |
| /* |
| * convert connectable fh to dentry |
| */ |
| static struct dentry *__cfh_to_dentry(struct super_block *sb, |
| struct ceph_nfs_confh *cfh) |
| { |
| struct ceph_mds_client *mdsc = &ceph_sb_to_client(sb)->mdsc; |
| struct inode *inode; |
| struct dentry *dentry; |
| struct ceph_vino vino; |
| int err; |
| |
| dout("__cfh_to_dentry %llx (%llx/%x)\n", |
| cfh->ino, cfh->parent_ino, cfh->parent_name_hash); |
| |
| vino.ino = cfh->ino; |
| vino.snap = CEPH_NOSNAP; |
| inode = ceph_find_inode(sb, vino); |
| if (!inode) { |
| struct ceph_mds_request *req; |
| |
| req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH, |
| USE_ANY_MDS); |
| if (IS_ERR(req)) |
| return ERR_PTR(PTR_ERR(req)); |
| |
| req->r_ino1 = vino; |
| req->r_ino2.ino = cfh->parent_ino; |
| req->r_ino2.snap = CEPH_NOSNAP; |
| req->r_path2 = kmalloc(16, GFP_NOFS); |
| snprintf(req->r_path2, 16, "%d", cfh->parent_name_hash); |
| req->r_num_caps = 1; |
| err = ceph_mdsc_do_request(mdsc, NULL, req); |
| ceph_mdsc_put_request(req); |
| inode = ceph_find_inode(sb, vino); |
| if (!inode) |
| return ERR_PTR(err ? err : -ESTALE); |
| } |
| |
| dentry = d_obtain_alias(inode); |
| if (IS_ERR(dentry)) { |
| pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n", |
| cfh->ino, inode); |
| iput(inode); |
| return dentry; |
| } |
| err = ceph_init_dentry(dentry); |
| if (err < 0) { |
| iput(inode); |
| return ERR_PTR(err); |
| } |
| dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry); |
| return dentry; |
| } |
| |
| static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid, |
| int fh_len, int fh_type) |
| { |
| if (fh_type == 1) |
| return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw); |
| else |
| return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw); |
| } |
| |
| /* |
| * get parent, if possible. |
| * |
| * FIXME: we could do better by querying the mds to discover the |
| * parent. |
| */ |
| static struct dentry *ceph_fh_to_parent(struct super_block *sb, |
| struct fid *fid, |
| int fh_len, int fh_type) |
| { |
| struct ceph_nfs_confh *cfh = (void *)fid->raw; |
| struct ceph_vino vino; |
| struct inode *inode; |
| struct dentry *dentry; |
| int err; |
| |
| if (fh_type == 1) |
| return ERR_PTR(-ESTALE); |
| |
| pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino, |
| cfh->parent_name_hash); |
| |
| vino.ino = cfh->ino; |
| vino.snap = CEPH_NOSNAP; |
| inode = ceph_find_inode(sb, vino); |
| if (!inode) |
| return ERR_PTR(-ESTALE); |
| |
| dentry = d_obtain_alias(inode); |
| if (IS_ERR(dentry)) { |
| pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n", |
| cfh->ino, inode); |
| iput(inode); |
| return dentry; |
| } |
| err = ceph_init_dentry(dentry); |
| if (err < 0) { |
| iput(inode); |
| return ERR_PTR(err); |
| } |
| dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry); |
| return dentry; |
| } |
| |
| const struct export_operations ceph_export_ops = { |
| .encode_fh = ceph_encode_fh, |
| .fh_to_dentry = ceph_fh_to_dentry, |
| .fh_to_parent = ceph_fh_to_parent, |
| }; |