posix/ctime: Fix stat(time attributes) inconsistency during readdirp

Problem:
   Creation of tar file on gluster volume throws warning
'file changed as we read it'

Cause:
   During readdirp, for few of the files whose inode is not
present, time attributes were served from backend. This caused
the ctime of few files to be different between before readdir
and after readdir by tar.

Solution:
  If ctime feature is enabled and inode is not present, don't
serve the time attributes from backend file, serve it from xattr.

Backport of:
> Patch: https://review.gluster.org/22540
> BUG: 1698078
> Change-Id: I427ef865f97399475faf5aa6ca495f7e317603ae
> Signed-off-by: Kotresh HR <khiremat@redhat.com>
(cherry picked from commit c56f102da21c5b69e656a055aaf736281596284d)

fixes: bz#1699703
Change-Id: I427ef865f97399475faf5aa6ca495f7e317603ae
Signed-off-by: Kotresh HR <khiremat@redhat.com>

4 files changed, 123 insertions, 26 deletions

diff --git a/tests/basic/ctime/ctime-readdir.c b/tests/basic/ctime/ctime-readdir.c
new file mode 100644
index 00000000000..8760db29ae8
--- /dev/null
+++ b/tests/basic/ctime/ctime-readdir.c
@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <dirent.h>
+#include <string.h>
+#include <assert.h>
+
+int
+main(int argc, char **argv)
+{
+    DIR *dir = NULL;
+    struct dirent *entry = NULL;
+    int ret = 0;
+    char *path = NULL;
+
+    assert(argc == 2);
+    path = argv[1];
+
+    dir = opendir(path);
+    if (!dir) {
+        printf("opendir(%s) failed.\n", path);
+        return -1;
+    }
+
+    while ((entry = readdir(dir)) != NULL) {
+    }
+    if (dir)
+        closedir(dir);
+
+    return ret;
+}
diff --git a/tests/basic/ctime/ctime-readdir.t b/tests/basic/ctime/ctime-readdir.t
new file mode 100644
index 00000000000..4564fc1b667
--- /dev/null
+++ b/tests/basic/ctime/ctime-readdir.t
@@ -0,0 +1,50 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+
+cleanup;
+
+TEST glusterd
+
+TEST $CLI volume create $V0 replica 3 ${H0}:$B0/brick{1,2,3};
+TEST $CLI volume set $V0 performance.stat-prefetch on
+TEST $CLI volume set $V0 performance.readdir-ahead off
+TEST $CLI volume start $V0;
+
+TEST glusterfs --volfile-id=$V0 --volfile-server=$H0 --entry-timeout=0 $M0;
+
+TEST mkdir $M0/dir0
+TEST "echo hello_world > $M0/dir0/FILE"
+
+ctime1=$(stat -c %Z $M0/dir0/FILE)
+echo "Mount change time: $ctime1"
+
+sleep 2
+
+#Write to back end directly to modify ctime of backend file
+TEST "echo write_from_backend >> $B0/brick1/dir0/FILE"
+TEST "echo write_from_backend >> $B0/brick2/dir0/FILE"
+TEST "echo write_from_backend >> $B0/brick3/dir0/FILE"
+echo "Backend change time"
+echo "brick1: $(stat -c %Z $B0/brick1/dir0/FILE)"
+echo "brick2: $(stat -c %Z $B0/brick2/dir0/FILE)"
+echo "brick3: $(stat -c %Z $B0/brick3/dir0/FILE)"
+
+#Stop and start to hit the case of no inode for readdir
+TEST umount $M0
+TEST $CLI volume stop $V0
+TEST $CLI volume start $V0
+TEST glusterfs --volfile-id=$V0 --volfile-server=$H0 --entry-timeout=0 $M0;
+
+TEST build_tester $(dirname $0)/ctime-readdir.c
+
+#Do readdir
+TEST ./$(dirname $0)/ctime-readdir $M0/dir0
+
+EXPECT "$ctime1" stat -c %Z $M0/dir0/FILE
+echo "Mount change time after readdir $(stat -c %Z $M0/dir0/FILE)"
+
+cleanup_tester $(dirname $0)/ctime-readdir
+
+cleanup;
diff --git a/xlators/storage/posix/src/posix-helpers.c b/xlators/storage/posix/src/posix-helpers.c
index 193afc5f3fa..37e33a918bb 100644
--- a/xlators/storage/posix/src/posix-helpers.c
+++ b/xlators/storage/posix/src/posix-helpers.c
@@ -832,17 +832,26 @@ posix_pstat(xlator_t *this, inode_t *inode, uuid_t gfid, const char *path,
 
     iatt_from_stat(&stbuf, &lstatbuf);
 
-    if (inode && priv->ctime) {
-        if (!inode_locked) {
-            ret = posix_get_mdata_xattr(this, path, -1, inode, &stbuf);
+    if (priv->ctime) {
+        if (inode) {
+            if (!inode_locked) {
+                ret = posix_get_mdata_xattr(this, path, -1, inode, &stbuf);
+            } else {
+                ret = __posix_get_mdata_xattr(this, path, -1, inode, &stbuf);
+            }
+            if (ret) {
+                gf_msg(this->name, GF_LOG_WARNING, errno, P_MSG_GETMDATA_FAILED,
+                       "posix get mdata failed on gfid: %s",
+                       uuid_utoa(inode->gfid));
+                goto out;
+            }
         } else {
-            ret = __posix_get_mdata_xattr(this, path, -1, inode, &stbuf);
-        }
-        if (ret) {
-            gf_msg(this->name, GF_LOG_WARNING, errno, P_MSG_GETMDATA_FAILED,
-                   "posix get mdata failed on gfid: %s",
-                   uuid_utoa(inode->gfid));
-            goto out;
+            ret = __posix_get_mdata_xattr(this, path, -1, NULL, &stbuf);
+            if (ret) {
+                gf_msg(this->name, GF_LOG_WARNING, errno, P_MSG_GETMDATA_FAILED,
+                       "posix get mdata failed on path: %s", path);
+                goto out;
+            }
         }
     }
 
diff --git a/xlators/storage/posix/src/posix-metadata.c b/xlators/storage/posix/src/posix-metadata.c
index 0ea90992714..7ff522519d8 100644
--- a/xlators/storage/posix/src/posix-metadata.c
+++ b/xlators/storage/posix/src/posix-metadata.c
@@ -79,6 +79,7 @@ posix_fetch_mdata_xattr(xlator_t *this, const char *real_path_arg, int _fd,
         fd_based_fop = _gf_true;
     }
     if (!(fd_based_fop || real_path_arg)) {
+        GF_VALIDATE_OR_GOTO(this->name, inode, out);
         MAKE_HANDLE_PATH(real_path, this, inode->gfid, NULL);
         if (!real_path) {
             uuid_utoa_r(inode->gfid, gfid_str);
@@ -114,14 +115,14 @@ posix_fetch_mdata_xattr(xlator_t *this, const char *real_path_arg, int _fd,
                          key,
                          real_path ? real_path
                                    : (real_path_arg ? real_path_arg : "null"),
-                         uuid_utoa(inode->gfid));
+                         inode ? uuid_utoa(inode->gfid) : "null");
         } else {
             gf_msg(this->name, GF_LOG_DEBUG, *op_errno, P_MSG_XATTR_FAILED,
                    "getxattr failed"
                    " on %s gfid: %s key: %s ",
                    real_path ? real_path
                              : (real_path_arg ? real_path_arg : "null"),
-                   uuid_utoa(inode->gfid), key);
+                   inode ? uuid_utoa(inode->gfid) : "null", key);
         }
         op_ret = -1;
         goto out;
@@ -148,7 +149,7 @@ posix_fetch_mdata_xattr(xlator_t *this, const char *real_path_arg, int _fd,
                "getxattr failed on "
                " on %s gfid: %s key: %s ",
                real_path ? real_path : (real_path_arg ? real_path_arg : "null"),
-               uuid_utoa(inode->gfid), key);
+               inode ? uuid_utoa(inode->gfid) : "null", key);
         goto out;
     }
 
@@ -233,9 +234,14 @@ __posix_get_mdata_xattr(xlator_t *this, const char *real_path, int _fd,
     int ret = -1;
     int op_errno = 0;
 
-    GF_VALIDATE_OR_GOTO(this->name, inode, out);
+    /* Handle readdirp: inode might be null, time attributes should be served
+     * from xattr not from backend's file attributes */
+    if (inode) {
+        ret = __inode_ctx_get1(inode, this, (uint64_t *)&mdata);
+    } else {
+        ret = -1;
+    }
 
-    ret = __inode_ctx_get1(inode, this, (uint64_t *)&mdata);
     if (ret == -1 || !mdata) {
         mdata = GF_CALLOC(1, sizeof(posix_mdata_t), gf_posix_mt_mdata_attr);
         if (!mdata) {
@@ -251,7 +257,9 @@ __posix_get_mdata_xattr(xlator_t *this, const char *real_path, int _fd,
              * is hit when in-memory status is lost due to brick
              * down scenario
              */
-            __inode_ctx_set1(inode, this, (uint64_t *)&mdata);
+            if (inode) {
+                __inode_ctx_set1(inode, this, (uint64_t *)&mdata);
+            }
         } else {
             /* Failed to get mdata from disk, xattr missing.
              * This happens on two cases.
@@ -278,7 +286,8 @@ __posix_get_mdata_xattr(xlator_t *this, const char *real_path, int _fd,
                  */
                 gf_msg(this->name, GF_LOG_WARNING, op_errno,
                        P_MSG_FETCHMDATA_FAILED, "file: %s: gfid: %s key:%s ",
-                       real_path ? real_path : "null", uuid_utoa(inode->gfid),
+                       real_path ? real_path : "null",
+                       inode ? uuid_utoa(inode->gfid) : "null",
                        GF_XATTR_MDATA_KEY);
                 GF_FREE(mdata);
                 ret = 0;
@@ -297,6 +306,10 @@ __posix_get_mdata_xattr(xlator_t *this, const char *real_path, int _fd,
         stbuf->ia_atime = mdata->atime.tv_sec;
         stbuf->ia_atime_nsec = mdata->atime.tv_nsec;
     }
+    /* Not set in inode context, hence free mdata */
+    if (!inode) {
+        GF_FREE(mdata);
+    }
 
 out:
     return ret;
@@ -416,6 +429,11 @@ posix_set_mdata_xattr(xlator_t *this, const char *real_path, int fd,
             }
         }
 
+        if ((flag->ctime == 0) && (flag->mtime == 0) && (flag->atime == 0)) {
+            ret = 0;
+            goto unlock;
+        }
+
         /* Earlier, mdata was updated only if the existing time is less
          * than the time to be updated. This would fail the scenarios
          * where mtime can be set to any time using the syscall. Hence
@@ -486,7 +504,6 @@ out:
         stbuf->ia_atime_nsec = mdata->atime.tv_nsec;
     }
 
-
     return ret;
 }
 
@@ -604,10 +621,6 @@ posix_set_ctime(call_frame_t *frame, xlator_t *this, const char *real_path,
 
     if (priv->ctime) {
         (void)posix_get_mdata_flag(frame->root->flags, &flag);
-        if ((flag.ctime == 0) && (flag.mtime == 0) && (flag.atime == 0)) {
-            goto out;
-        }
-
         if (frame->root->ctime.tv_sec == 0) {
             gf_msg(this->name, GF_LOG_WARNING, errno, P_MSG_SETMDATA_FAILED,
                    "posix set mdata failed, No ctime : %s gfid:%s", real_path,
@@ -643,9 +656,6 @@ posix_set_parent_ctime(call_frame_t *frame, xlator_t *this,
 
     if (inode && priv->ctime) {
         (void)posix_get_parent_mdata_flag(frame->root->flags, &flag);
-        if ((flag.ctime == 0) && (flag.mtime == 0) && (flag.atime == 0)) {
-            goto out;
-        }
         ret = posix_set_mdata_xattr(this, real_path, fd, inode,
                                     &frame->root->ctime, stbuf, &flag,
                                     _gf_false);
@@ -655,7 +665,6 @@ posix_set_parent_ctime(call_frame_t *frame, xlator_t *this,
                    uuid_utoa(inode->gfid));
         }
     }
-out:
     return;
 }