LU-11753 obdclass: index_page support variable length rec

mdd_dir_is_empty() may readdir from other MDT if directory
is striped or remote, in this case, it will issue OBD_IDX_READ
RPC to fetch dir page, and on remote MDT dt_index_page_build()
is called to build page, but this function doesn't support
variable length record, so it may miscalculate offset in
reading, which may cause crash.

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: Ia25a0aca52fb1323ea64a7ff72bf6022754af32c
Reviewed-on: https://review.whamcloud.com/33837
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Stephan Thiell <sthiell@stanford.edu>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/obdclass/dt_object.c b/lustre/obdclass/dt_object.c
index 95a9070..faff31f 100644 (file)
--- a/lustre/obdclass/dt_object.c
+++ b/lustre/obdclass/dt_object.c
@@ -721,8 +721,12 @@ static int dt_index_page_build(const struct lu_env *env, union lu_page *lp,
        struct idx_info *ii = (struct idx_info *)arg;
        struct lu_idxpage *lip = &lp->lp_idx;
        char *entry;
        struct idx_info *ii = (struct idx_info *)arg;
        struct lu_idxpage *lip = &lp->lp_idx;
        char *entry;

-       size_t size;
+       __u64 hash;
+       __u16 hashsize = 0;
+       __u16 keysize = 0;
+       __u16 recsize;

        int rc;
        int rc;

+

        ENTRY;
 
        if (nob < LIP_HDR_SIZE)
        ENTRY;
 
        if (nob < LIP_HDR_SIZE)


@@ -733,20 +737,12 @@ static int dt_index_page_build(const struct lu_env *env, union lu_page *lp,
        lip->lip_magic = LIP_MAGIC;
        nob           -= LIP_HDR_SIZE;
 
        lip->lip_magic = LIP_MAGIC;
        nob           -= LIP_HDR_SIZE;
 

-       /* compute size needed to store a key/record pair */
-       size = ii->ii_recsize + ii->ii_keysize;
-       if ((ii->ii_flags & II_FL_NOHASH) == 0)
-               /* add hash if the client wants it */
-               size += sizeof(__u64);
+       /* client wants to the 64-bit hash value associated with each record */
+       if (!(ii->ii_flags & II_FL_NOHASH))
+               hashsize = sizeof(hash);

 
        entry = lip->lip_entries;
        do {
 
        entry = lip->lip_entries;
        do {

-               char *tmp_entry = entry;
-               struct dt_key *key;
-               __u64 hash;
-               __u16 keysize;
-               __u16 recsize;
-

                /* fetch 64-bit hash value */
                hash = iops->store(env, it);
                ii->ii_hash_end = hash;
                /* fetch 64-bit hash value */
                hash = iops->store(env, it);
                ii->ii_hash_end = hash;


@@ -756,58 +752,54 @@ static int dt_index_page_build(const struct lu_env *env, union lu_page *lp,
                                GOTO(out, rc = 0);
                }
 
                                GOTO(out, rc = 0);
                }
 

-               if (nob < size) {
-                       if (lip->lip_nr == 0)
+               if (!(ii->ii_flags & II_FL_NOKEY)) {
+                       keysize = iops->key_size(env, it);
+                       if (!(ii->ii_flags & II_FL_VARKEY) &&
+                           keysize != ii->ii_keysize) {
+                               CERROR("keysize mismatch %hu != %hu.\n",
+                                      keysize, ii->ii_keysize);

                                GOTO(out, rc = -EINVAL);
                                GOTO(out, rc = -EINVAL);

-                       GOTO(out, rc = 0);
-               }
-
-               if (!(ii->ii_flags & II_FL_NOHASH)) {
-                       /*
-                        * client wants to the 64-bit hash value associated
-                        * with each record
-                        */
-                       memcpy(tmp_entry, &hash, sizeof(hash));
-                       tmp_entry += sizeof(hash);
+                       }

                }
 
                }
 

-               if (ii->ii_flags & II_FL_VARKEY)
-                       keysize = iops->key_size(env, it);
+               /* and finally the record */
+               if (ii->ii_flags & II_FL_VARREC)
+                       recsize = iops->rec_size(env, it, attr);

                else
                else

-                       keysize = ii->ii_keysize;
+                       recsize = ii->ii_recsize;

 
 

-               if (!(ii->ii_flags & II_FL_NOKEY)) {
-                       /* then the key value */
-                       key = iops->key(env, it);
-                       memcpy(tmp_entry, key, keysize);
-                       tmp_entry += keysize;
+               if (nob < hashsize + keysize + recsize) {
+                       if (lip->lip_nr == 0)
+                               GOTO(out, rc = -E2BIG);
+                       GOTO(out, rc = 0);

                }
 
                }
 

-               /* and finally the record */
-               rc = iops->rec(env, it, (struct dt_rec *)tmp_entry, attr);
-               if (rc != -ESTALE) {
-                       if (rc != 0)
-                               GOTO(out, rc);
-
+               rc = iops->rec(env, it,
+                              (struct dt_rec *)(entry + hashsize + keysize),
+                              attr);
+               if (!rc) {
+                       if (hashsize)
+                               memcpy(entry, &hash, hashsize);
+                       if (keysize) {
+                               struct dt_key *key;
+
+                               key = iops->key(env, it);
+                               memcpy(entry + hashsize, key, keysize);
+                       }

                        /* hash/key/record successfully copied! */
                        lip->lip_nr++;
                        if (unlikely(lip->lip_nr == 1 && ii->ii_count == 0))
                                ii->ii_hash_start = hash;
                        /* hash/key/record successfully copied! */
                        lip->lip_nr++;
                        if (unlikely(lip->lip_nr == 1 && ii->ii_count == 0))
                                ii->ii_hash_start = hash;

-
-                       if (ii->ii_flags & II_FL_VARREC)
-                               recsize = iops->rec_size(env, it, attr);
-                       else
-                               recsize = ii->ii_recsize;
-
-                       entry = tmp_entry + recsize;
-                       nob -= size;
+                       entry += hashsize + keysize + recsize;
+                       nob -= hashsize + keysize + recsize;
+               } else if (rc != -ESTALE) {
+                       GOTO(out, rc);

                }
 
                /* move on to the next record */
                do {
                        rc = iops->next(env, it);
                } while (rc == -ESTALE);
                }
 
                /* move on to the next record */
                do {
                        rc = iops->next(env, it);
                } while (rc == -ESTALE);

-

        } while (rc == 0);
 
        GOTO(out, rc);
        } while (rc == 0);
 
        GOTO(out, rc);