performance/write-behind: initialize lock in wb-file before wb-file is set in fd-ctx.

- Consider a combination of fuse->quick-read->read-ahead->wb->client.
    quick-read can do open-behind (open is returned as success even
    before it is issued to backend) and hence the fd can already be
    in the list of open fds of the inode. A flush call on some other
    fd opened on the same inode, will result in ra_flush issuing flush
    calls to all the fds opened on the same inode. This can result in
    wb_flush trying to hold a lock on non-initialized lock there by causing
    memory corruption.

Signed-off-by: Raghavendra G <raghavendra@gluster.com>
Signed-off-by: Anand Avati <avati@gluster.com>

BUG: 2679 (Crash in GlusterFS 3.0.5 in GSP)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2679

1 files changed, 31 insertions, 25 deletions

diff --git a/xlators/performance/write-behind/src/write-behind.c b/xlators/performance/write-behind/src/write-behind.c
index 43956a920..952de57b7 100644
--- a/xlators/performance/write-behind/src/write-behind.c
+++ b/xlators/performance/write-behind/src/write-behind.c
@@ -297,7 +297,7 @@ wb_file_t *
 wb_file_create (xlator_t *this, fd_t *fd, int32_t flags)
 {
         wb_file_t *file = NULL;
-        wb_conf_t *conf = this->private; 
+        wb_conf_t *conf = this->private;
 
         file = GF_CALLOC (1, sizeof (*file), gf_wb_mt_wb_file_t);
         if (file == NULL) {
@@ -307,7 +307,7 @@ wb_file_create (xlator_t *this, fd_t *fd, int32_t flags)
         INIT_LIST_HEAD (&file->request);
         INIT_LIST_HEAD (&file->passive_requests);
 
-        /* 
+        /*
            fd_ref() not required, file should never decide the existance of
            an fd
         */
@@ -318,6 +318,8 @@ wb_file_create (xlator_t *this, fd_t *fd, int32_t flags)
         file->window_conf = conf->window_size;
         file->flags = flags;
 
+        LOCK_INIT (&file->lock);
+
         fd_ctx_set (fd, this, (uint64_t)(long)file);
 
 out:
@@ -1325,21 +1327,23 @@ wb_open_cbk (call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
                         goto out;
                 }
 
-                /* If O_DIRECT then, we disable chaching */
-                if (((flags & O_DIRECT) == O_DIRECT)
-                    || ((flags & O_ACCMODE) == O_RDONLY)
-                    || (((flags & O_SYNC) == O_SYNC)
-                        && conf->enable_O_SYNC == _gf_true)) { 
-                        file->window_conf = 0;
-                }
+                LOCK (&file->lock);
+                {
+                        /* If O_DIRECT then, we disable chaching */
+                        if (((flags & O_DIRECT) == O_DIRECT)
+                            || ((flags & O_ACCMODE) == O_RDONLY)
+                            || (((flags & O_SYNC) == O_SYNC)
+                                && conf->enable_O_SYNC == _gf_true)) {
+                                file->window_conf = 0;
+                        }
 
-                if (wbflags & GF_OPEN_NOWB) {
-                        file->disabled = 1;
+                        if (wbflags & GF_OPEN_NOWB) {
+                                file->disabled = 1;
+                        }
                 }
- 
-                LOCK_INIT (&file->lock);
+                UNLOCK (&file->lock);
         }
-        
+
 out:
         STACK_UNWIND_STRICT (open, frame, op_ret, op_errno, fd);
         return 0;
@@ -1400,22 +1404,24 @@ wb_create_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
                         goto out;
                 }
 
-                /* If O_DIRECT then, we disable chaching */
-                if (frame->local) {
-                        if (((flags & O_DIRECT) == O_DIRECT)
-                            || ((flags & O_ACCMODE) == O_RDONLY)
-                            || (((flags & O_SYNC) == O_SYNC)
-                                && (conf->enable_O_SYNC == _gf_true))) { 
-                                file->window_conf = 0;
+                LOCK (&file->lock);
+                {
+                        /* If O_DIRECT then, we disable chaching */
+                        if (frame->local) {
+                                if (((flags & O_DIRECT) == O_DIRECT)
+                                    || ((flags & O_ACCMODE) == O_RDONLY)
+                                    || (((flags & O_SYNC) == O_SYNC)
+                                        && (conf->enable_O_SYNC == _gf_true))) {
+                                        file->window_conf = 0;
+                                }
                         }
                 }
-
-                LOCK_INIT (&file->lock);
+                UNLOCK (&file->lock);
         }
-        
+
         frame->local = NULL;
 
-out:        
+out:
         STACK_UNWIND_STRICT (create, frame, op_ret, op_errno, fd, inode, buf,
                              preparent, postparent);
         return 0;