libglusterfsclient: Revert and re-do readdir conformance

This commit basically reverts the previous readdir conformance
patch I sent a few days back. That commit had a completely retarded
and broken way of maintaining per-directory dirent.

It was broken for two reasons:
1. Creating a wrapper structure around the directory's fd_t
only for storing a struct dirent is not clean enough. This commit
takes a better approach by storing the dirent in fd_t context.
This dirent is valid only if the fd_t refers to a directory.

2. That commit was made and tested under the assumption (..stupidity
is a better word..) that only opendir call is used for opening a
directory. That is not correct. Directories are also opened using the
open syscall. The point is, glusterfs_open returns an fd_t and so did
glusterfs_opendir. The previous patch actually changed opendir to
return a new wrapper structure. That is fine, if we go by the POSIX
definition of open and opendir because, they're both supposed to
return different types, an int and a DIR*. However, in
libglusterfsclient, all other code assumes that directory handles
corresponding to DIR* and file descriptors corresponding to int types
are the same type, resulting in use of the same locking and fd context
addition/extraction code. So a directory opened using opendir returned
a wrapper structure which went down into the libglusterfsclient stack
where some function called a lock on the handle assuming it was an
fd_t, since it is not and dereferencing of the supposed fd->inode->lock
results in a seg fault.

Obviously, this didnt show up till unfs3 used open() to open a
directory and not opendir.

Signed-off-by: Anand V. Avati <avati@amp.gluster.com>

1 files changed, 5 insertions, 12 deletions

diff --git a/libglusterfsclient/src/libglusterfsclient-internals.h b/libglusterfsclient/src/libglusterfsclient-internals.h
index 4cdde26e78b..40ad6f6929f 100755
--- a/libglusterfsclient/src/libglusterfsclient-internals.h
+++ b/libglusterfsclient/src/libglusterfsclient-internals.h
@@ -83,6 +83,11 @@ typedef struct {
         pthread_mutex_t lock;
         off_t offset;
         libglusterfs_client_ctx_t *ctx;
+        /* `man readdir` says readdir is non-re-entrant
+         * only if two readdirs are racing on the same
+         * handle.
+         */
+	struct dirent dirp;
 } libglusterfs_client_fd_ctx_t;
 
 typedef struct libglusterfs_client_async_local {
@@ -231,16 +236,4 @@ struct vmp_entry {
 };
 
 
-/* Internal directory handle inited in opendir.
- * This is needed in order to store a per-handle
- * dirent structure.
- */
-struct libgf_dir_handle {
-        fd_t *dirfd;
-        struct dirent dirp;
-};
-
-
-
-
 #endif