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03f219041f
Converting a file handle to a dentry can be done call after the inode unlink. This means that __fh_to_dentry() requires an extra check to verify the number of links is not 0. The issue can be easily reproduced using xfstest generic/426, which does something like: name_to_handle_at(&fh) echo 3 > /proc/sys/vm/drop_caches unlink() open_by_handle_at(&fh) The call to open_by_handle_at() should fail, as the file doesn't exist anymore. Link: http://tracker.ceph.com/issues/19958 Signed-off-by: Luis Henriques <lhenriques@suse.com> Reviewed-by: "Yan, Zheng" <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
243 lines
5.7 KiB
C
243 lines
5.7 KiB
C
#include <linux/ceph/ceph_debug.h>
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#include <linux/exportfs.h>
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#include <linux/slab.h>
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#include <asm/unaligned.h>
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#include "super.h"
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#include "mds_client.h"
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/*
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* Basic fh
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*/
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struct ceph_nfs_fh {
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u64 ino;
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} __attribute__ ((packed));
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/*
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* Larger fh that includes parent ino.
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*/
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struct ceph_nfs_confh {
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u64 ino, parent_ino;
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} __attribute__ ((packed));
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static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
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struct inode *parent_inode)
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{
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int type;
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struct ceph_nfs_fh *fh = (void *)rawfh;
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struct ceph_nfs_confh *cfh = (void *)rawfh;
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int connected_handle_length = sizeof(*cfh)/4;
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int handle_length = sizeof(*fh)/4;
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/* don't re-export snaps */
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if (ceph_snap(inode) != CEPH_NOSNAP)
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return -EINVAL;
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if (parent_inode && (*max_len < connected_handle_length)) {
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*max_len = connected_handle_length;
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return FILEID_INVALID;
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} else if (*max_len < handle_length) {
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*max_len = handle_length;
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return FILEID_INVALID;
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}
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if (parent_inode) {
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dout("encode_fh %llx with parent %llx\n",
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ceph_ino(inode), ceph_ino(parent_inode));
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cfh->ino = ceph_ino(inode);
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cfh->parent_ino = ceph_ino(parent_inode);
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*max_len = connected_handle_length;
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type = FILEID_INO32_GEN_PARENT;
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} else {
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dout("encode_fh %llx\n", ceph_ino(inode));
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fh->ino = ceph_ino(inode);
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*max_len = handle_length;
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type = FILEID_INO32_GEN;
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}
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return type;
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}
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static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
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{
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struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
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struct inode *inode;
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struct ceph_vino vino;
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int err;
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vino.ino = ino;
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vino.snap = CEPH_NOSNAP;
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inode = ceph_find_inode(sb, vino);
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if (!inode) {
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struct ceph_mds_request *req;
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int mask;
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req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
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USE_ANY_MDS);
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if (IS_ERR(req))
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return ERR_CAST(req);
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mask = CEPH_STAT_CAP_INODE;
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if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
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mask |= CEPH_CAP_XATTR_SHARED;
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req->r_args.getattr.mask = cpu_to_le32(mask);
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req->r_ino1 = vino;
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req->r_num_caps = 1;
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err = ceph_mdsc_do_request(mdsc, NULL, req);
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inode = req->r_target_inode;
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if (inode)
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ihold(inode);
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ceph_mdsc_put_request(req);
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if (!inode)
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return ERR_PTR(-ESTALE);
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if (inode->i_nlink == 0) {
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iput(inode);
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return ERR_PTR(-ESTALE);
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}
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}
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return d_obtain_alias(inode);
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}
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/*
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* convert regular fh to dentry
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*/
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static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
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struct fid *fid,
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int fh_len, int fh_type)
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{
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struct ceph_nfs_fh *fh = (void *)fid->raw;
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if (fh_type != FILEID_INO32_GEN &&
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fh_type != FILEID_INO32_GEN_PARENT)
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return NULL;
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if (fh_len < sizeof(*fh) / 4)
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return NULL;
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dout("fh_to_dentry %llx\n", fh->ino);
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return __fh_to_dentry(sb, fh->ino);
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}
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static struct dentry *__get_parent(struct super_block *sb,
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struct dentry *child, u64 ino)
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{
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struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
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struct ceph_mds_request *req;
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struct inode *inode;
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int mask;
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int err;
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req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPPARENT,
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USE_ANY_MDS);
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if (IS_ERR(req))
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return ERR_CAST(req);
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if (child) {
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req->r_inode = d_inode(child);
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ihold(d_inode(child));
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} else {
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req->r_ino1 = (struct ceph_vino) {
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.ino = ino,
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.snap = CEPH_NOSNAP,
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};
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}
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mask = CEPH_STAT_CAP_INODE;
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if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
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mask |= CEPH_CAP_XATTR_SHARED;
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req->r_args.getattr.mask = cpu_to_le32(mask);
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req->r_num_caps = 1;
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err = ceph_mdsc_do_request(mdsc, NULL, req);
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inode = req->r_target_inode;
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if (inode)
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ihold(inode);
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ceph_mdsc_put_request(req);
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if (!inode)
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return ERR_PTR(-ENOENT);
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return d_obtain_alias(inode);
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}
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static struct dentry *ceph_get_parent(struct dentry *child)
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{
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/* don't re-export snaps */
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if (ceph_snap(d_inode(child)) != CEPH_NOSNAP)
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return ERR_PTR(-EINVAL);
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dout("get_parent %p ino %llx.%llx\n",
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child, ceph_vinop(d_inode(child)));
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return __get_parent(child->d_sb, child, 0);
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}
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/*
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* convert regular fh to parent
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*/
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static struct dentry *ceph_fh_to_parent(struct super_block *sb,
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struct fid *fid,
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int fh_len, int fh_type)
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{
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struct ceph_nfs_confh *cfh = (void *)fid->raw;
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struct dentry *dentry;
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if (fh_type != FILEID_INO32_GEN_PARENT)
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return NULL;
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if (fh_len < sizeof(*cfh) / 4)
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return NULL;
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dout("fh_to_parent %llx\n", cfh->parent_ino);
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dentry = __get_parent(sb, NULL, cfh->ino);
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if (unlikely(dentry == ERR_PTR(-ENOENT)))
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dentry = __fh_to_dentry(sb, cfh->parent_ino);
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return dentry;
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}
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static int ceph_get_name(struct dentry *parent, char *name,
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struct dentry *child)
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{
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struct ceph_mds_client *mdsc;
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struct ceph_mds_request *req;
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int err;
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mdsc = ceph_inode_to_client(d_inode(child))->mdsc;
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req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
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USE_ANY_MDS);
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if (IS_ERR(req))
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return PTR_ERR(req);
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inode_lock(d_inode(parent));
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req->r_inode = d_inode(child);
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ihold(d_inode(child));
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req->r_ino2 = ceph_vino(d_inode(parent));
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req->r_parent = d_inode(parent);
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set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
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req->r_num_caps = 2;
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err = ceph_mdsc_do_request(mdsc, NULL, req);
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inode_unlock(d_inode(parent));
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if (!err) {
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struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
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memcpy(name, rinfo->dname, rinfo->dname_len);
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name[rinfo->dname_len] = 0;
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dout("get_name %p ino %llx.%llx name %s\n",
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child, ceph_vinop(d_inode(child)), name);
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} else {
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dout("get_name %p ino %llx.%llx err %d\n",
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child, ceph_vinop(d_inode(child)), err);
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}
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ceph_mdsc_put_request(req);
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return err;
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}
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const struct export_operations ceph_export_ops = {
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.encode_fh = ceph_encode_fh,
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.fh_to_dentry = ceph_fh_to_dentry,
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.fh_to_parent = ceph_fh_to_parent,
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.get_parent = ceph_get_parent,
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.get_name = ceph_get_name,
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};
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