posix: use the correct op_errno

Problem:
If readdir/fstat was performed on a directory that was removed,
posix_fd_ctx_get() fails with ENOENT but we incorrectly use the ret
value (-1 in this case) as op_errno, logging "Operation not permitted"
messages in the brick logs. Also in case of fstat, the -1 op_errno was
also propagated to the client via stack unwind, causing the message to
appear in protocol/client logs as well.

Fix:
Use the right op_errno in readdir, fstat and writev. Also, if
posix_fd_ctx_get() failed with ENOENT, convert it into EBADF because
ENOENT is not a valid error for an fd operation.

> Reviewed-on: https://review.gluster.org/17414
> Smoke: Gluster Build System <jenkins@build.gluster.org>
> Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
> Tested-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
> Reviewed-by: Amar Tumballi <amarts@redhat.com>
> CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
(cherry picked from commit de92c363c95d16966dbcc9d8763fd4448dd84d13)

Change-Id: Ie43c0789d5040ec73b7cf885d015a183b8c64d70
BUG: 1457732
Signed-off-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-on: https://review.gluster.org/17515
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

2 files changed, 14 insertions, 8 deletions

diff --git a/xlators/storage/posix/src/posix-helpers.c b/xlators/storage/posix/src/posix-helpers.c
index 3a97da6a79f..d39a77bbe06 100644
--- a/xlators/storage/posix/src/posix-helpers.c
+++ b/xlators/storage/posix/src/posix-helpers.c
@@ -1695,7 +1695,13 @@ __posix_fd_ctx_get (fd_t *fd, xlator_t *this, struct posix_fd **pfd_p,
         if (fd->inode->ia_type == IA_IFDIR) {
                 dir = sys_opendir (real_path);
                 if (!dir) {
-                        op_errno = errno;
+                        (errno == ENOENT) ? (op_errno = EBADF) :
+                                            (op_errno = errno);
+                        gf_msg (this->name, GF_LOG_ERROR, errno,
+                                P_MSG_READ_FAILED,
+                                "Failed to get anonymous fd for "
+                                "real_path: %s. Returning %s.", real_path,
+                                strerror(op_errno));
                         GF_FREE (pfd);
                         pfd = NULL;
                         goto out;
@@ -1716,11 +1722,13 @@ __posix_fd_ctx_get (fd_t *fd, xlator_t *this, struct posix_fd **pfd_p,
                         _fd = open (unlink_path, fd->flags);
                 }
                 if (_fd == -1) {
-                        op_errno = errno;
-                        gf_msg (this->name, GF_LOG_ERROR, op_errno,
+                        (errno == ENOENT) ? (op_errno = EBADF) :
+                                            (op_errno = errno);
+                        gf_msg (this->name, GF_LOG_ERROR, errno,
                                 P_MSG_READ_FAILED,
-                                "Failed to get anonymous "
-                                "real_path: %s _fd = %d", real_path, _fd);
+                                "Failed to get anonymous fd for "
+                                "real_path: %s. Returning %s.", real_path,
+                                strerror(op_errno));
                         GF_FREE (pfd);
                         pfd = NULL;
                         goto out;
diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c
index f53207fc5a8..47a477e4470 100644
--- a/xlators/storage/posix/src/posix.c
+++ b/xlators/storage/posix/src/posix.c
@@ -3396,7 +3396,6 @@ posix_writev (call_frame_t *frame, xlator_t *this, fd_t *fd,
         if (ret < 0) {
                 gf_msg (this->name, GF_LOG_WARNING, ret, P_MSG_PFD_NULL,
                         "pfd is NULL from fd=%p", fd);
-                op_errno = -ret;
                 goto out;
         }
 
@@ -5933,7 +5932,6 @@ posix_fstat (call_frame_t *frame, xlator_t *this,
         if (ret < 0) {
                 gf_msg (this->name, GF_LOG_WARNING, op_errno, P_MSG_PFD_NULL,
                         "pfd is NULL, fd=%p", fd);
-                op_errno = -ret;
                 goto out;
         }
 
@@ -6365,7 +6363,7 @@ posix_do_readdir (call_frame_t *frame, xlator_t *this,
 
         ret = posix_fd_ctx_get (fd, this, &pfd, &op_errno);
         if (ret < 0) {
-                gf_msg (this->name, GF_LOG_WARNING, -ret, P_MSG_PFD_NULL,
+                gf_msg (this->name, GF_LOG_WARNING, op_errno, P_MSG_PFD_NULL,
                         "pfd is NULL, fd=%p", fd);
                 goto out;
         }