cluster/afr: Fix gfid unsplit code when renamed filename exceeds NAME_MAX

Summary:
- We noticed some folks name their files all the way up to NAME_MAX (usually 255) and when split-brain is encountered, we fail to heal the file.
- This diff puts an upper bound on the number of bytes we will snprintf into the buffer so that we do not fail the rename.
- This is a port of D3646254 to 3.8

Test Plan: Prove test -- can show it fails without patch as well.

Reviewers: #posix_storage, rwareing

Reviewed By: rwareing

Change-Id: I51c6b28374d4a3f21e29044cb727b4b1da7b69e1
Reviewed-on: https://review.gluster.org/18194
Reviewed-by: Shreyas Siravara <sshreyas@fb.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.org>

1 files changed, 14 insertions, 1 deletions

diff --git a/xlators/cluster/afr/src/afr-self-heal-name.c b/xlators/cluster/afr/src/afr-self-heal-name.c
index 9ca56f8bd9d..8e5546a702f 100644
--- a/xlators/cluster/afr/src/afr-self-heal-name.c
+++ b/xlators/cluster/afr/src/afr-self-heal-name.c
@@ -84,6 +84,19 @@ _afr_sh_create_unsplit_loc (struct afr_reply *replies, const int child_idx,
                 ret = ENOMEM;
                 goto err;
         }
+
+        /*
+         * Attempting to do a rename on a file that is too long
+         * will return ENAMETOOLONG and heals will fail. Therefore
+         * we should just limit the name to NAME_MAX
+         * knowing that the filename will be truncated.
+         */
+        if (new_name_len > NAME_MAX) {
+                gf_log ("afr", GF_LOG_WARNING,
+                        "Filename too long, truncating to %d bytes.", NAME_MAX);
+                new_name_len = NAME_MAX;
+        }
+
         snprintf (new_name, new_name_len, ".unsplit_%s_%s", tmp_gfid_str,
                 loc->name);
         unsplit_loc->name = new_name;
@@ -376,7 +389,7 @@ __afr_selfheal_assign_gfid (xlator_t *this, inode_t *parent, uuid_t pargfid,
                                 continue;
                         }
                         gf_log (this->name, GF_LOG_WARNING,
-                                "type[%d] = %d (not %d)", i, 
+                                "type[%d] = %d (not %d)", i,
                                 replies[i].poststat.ia_type, ia_type);
                         if (ia_type != IA_INVAL) {
                                 ret = -EIO;