core: avoid dynamic TLS allocation when possible

Some interdependencies between logging and memory management functions
make it impossible to use the logging framework before initializing
memory subsystem because they both depend on Thread Local Storage
allocated through pthread_key_create() during initialization.

This causes a crash when we try to log something very early in the
initialization phase.

To prevent this, several dynamically allocated TLS structures have
been replaced by static TLS reserved at compile time using '__thread'
keyword. This also reduces the number of error sources, making
initialization simpler.

Updates: bz#1193929
Change-Id: I8ea2e072411e30790d50084b6b7e909c7bb01d50
Signed-off-by: Xavi Hernandez <xhernandez@redhat.com>

2 files changed, 5 insertions, 49 deletions

diff --git a/xlators/features/changelog/lib/src/gf-changelog-helpers.c b/xlators/features/changelog/lib/src/gf-changelog-helpers.c
index 7acc5742c25..75f8a6dfc08 100644
--- a/xlators/features/changelog/lib/src/gf-changelog-helpers.c
+++ b/xlators/features/changelog/lib/src/gf-changelog-helpers.c
@@ -58,20 +58,7 @@ gf_rfc3986_encode_space_newline(unsigned char *s, char *enc, char *estr)
  *       made a part of libglusterfs.
  */
 
-static pthread_key_t rl_key;
-static pthread_once_t rl_once = PTHREAD_ONCE_INIT;
-
-static void
-readline_destructor(void *ptr)
-{
-    GF_FREE(ptr);
-}
-
-static void
-readline_once(void)
-{
-    pthread_key_create(&rl_key, readline_destructor);
-}
+static __thread read_line_t thread_tsd = {};
 
 static ssize_t
 my_read(read_line_t *tsd, int fd, char *ptr)
@@ -91,27 +78,6 @@ my_read(read_line_t *tsd, int fd, char *ptr)
     return 1;
 }
 
-static int
-gf_readline_init_once(read_line_t **tsd)
-{
-    if (pthread_once(&rl_once, readline_once) != 0)
-        return -1;
-
-    *tsd = pthread_getspecific(rl_key);
-    if (*tsd)
-        goto out;
-
-    *tsd = GF_CALLOC(1, sizeof(**tsd), gf_changelog_mt_libgfchangelog_rl_t);
-    if (!*tsd)
-        return -1;
-
-    if (pthread_setspecific(rl_key, *tsd) != 0)
-        return -1;
-
-out:
-    return 0;
-}
-
 ssize_t
 gf_readline(int fd, void *vptr, size_t maxlen)
 {
@@ -119,10 +85,7 @@ gf_readline(int fd, void *vptr, size_t maxlen)
     size_t rc = 0;
     char c = ' ';
     char *ptr = NULL;
-    read_line_t *tsd = NULL;
-
-    if (gf_readline_init_once(&tsd))
-        return -1;
+    read_line_t *tsd = &thread_tsd;
 
     ptr = vptr;
     for (n = 1; n < maxlen; n++) {
@@ -145,10 +108,7 @@ off_t
 gf_lseek(int fd, off_t offset, int whence)
 {
     off_t off = 0;
-    read_line_t *tsd = NULL;
-
-    if (gf_readline_init_once(&tsd))
-        return -1;
+    read_line_t *tsd = &thread_tsd;
 
     off = sys_lseek(fd, offset, whence);
     if (off == -1)
@@ -163,10 +123,7 @@ gf_lseek(int fd, off_t offset, int whence)
 int
 gf_ftruncate(int fd, off_t length)
 {
-    read_line_t *tsd = NULL;
-
-    if (gf_readline_init_once(&tsd))
-        return -1;
+    read_line_t *tsd = &thread_tsd;
 
     if (sys_ftruncate(fd, 0))
         return -1;
diff --git a/xlators/features/changelog/lib/src/gf-changelog.c b/xlators/features/changelog/lib/src/gf-changelog.c
index 7ed9e553e68..d6acb37f3ef 100644
--- a/xlators/features/changelog/lib/src/gf-changelog.c
+++ b/xlators/features/changelog/lib/src/gf-changelog.c
@@ -237,9 +237,8 @@ gf_changelog_init_master()
 {
     int ret = 0;
 
-    mem_pools_init_early();
     ret = gf_changelog_init_context();
-    mem_pools_init_late();
+    mem_pools_init();
 
     return ret;
 }