telldir()/seekdir() portability fixes

POSIX says that an offset obtained from telldir() can only be used
on the same DIR *. Linux is abls to reuse the offset accross
closedir()/opendir() for a given directory, but this is not portable
and such a behavior should be fixed.

An incomplete fix for the posix xlator was merged in
http://review.gluster.org/8933
This change set completes it.

- Perform the same fix index xlator.
- Use appropriate casts and variable types so that 32 bit signed
  offsets obtained by telldir() do not get clobbered when copied into
  64 bit signed types.
- modify afr-self-heald.c so that it does not use anonymous fd,
  since this will cause closedir()/opendir() between each
  syncop_readdir(). On failure we fallback to anonymous fs
  only for Linux so that we can cope with updated client vs not
  updated brick.
- Avoid sending an EINVAL when the client request for the EOF offset.
  Here we fix an error in previous fix for posix xlator: since we
  fill each directory entry with the offset of the next entry, we
  must consider as EOF the offset of the last entry, and not the
  value of telldir() after we read it.

This is a backport of I59fb7f06a872c4f98987105792d648141c258c6a

BUG: 1138897
Change-Id: I1e9f3e4a7d780b98adf6d9f197ee2198d43ef94d
Signed-off-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-on: http://review.gluster.org/9084
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra Bhat <raghavendra@redhat.com>

1 files changed, 17 insertions, 9 deletions

diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c
index d8599881fb7..c1730e8d337 100644
--- a/xlators/storage/posix/src/posix.c
+++ b/xlators/storage/posix/src/posix.c
@@ -4853,6 +4853,7 @@ posix_fill_readdir (fd_t *fd, DIR *dir, off_t off, size_t size,
                     gf_dirent_t *entries, xlator_t *this, int32_t skip_dirs)
 {
         off_t     in_case = -1;
+        off_t     last_off = 0;
         size_t    filled = 0;
         int             count = 0;
         char      entrybuf[sizeof(struct dirent) + 256 + 8];
@@ -4888,11 +4889,11 @@ posix_fill_readdir (fd_t *fd, DIR *dir, off_t off, size_t size,
         } else {
                 seekdir (dir, off);
 #ifndef GF_LINUX_HOST_OS
-                if (telldir(dir) != (long)off && off != pfd->dir_eof) {
+                if ((u_long)telldir(dir) != off && off != pfd->dir_eof) {
                         gf_log (THIS->name, GF_LOG_ERROR,
-                                "seekdir(%ld) failed on dir=%p: "
+                                "seekdir(0x%llx) failed on dir=%p: "
                                 "Invalid argument (offset reused from "
-                                "another DIR * structure?)", (long)off, dir);
+                                "another DIR * structure?)", off, dir);
                         errno = EINVAL;
                         count = -1;
                         goto out;
@@ -4901,7 +4902,7 @@ posix_fill_readdir (fd_t *fd, DIR *dir, off_t off, size_t size,
         }
 
         while (filled <= size) {
-                in_case = telldir (dir);
+                in_case = (u_long)telldir (dir);
 
                 if (in_case == -1) {
                         gf_log (THIS->name, GF_LOG_ERROR,
@@ -4961,13 +4962,13 @@ posix_fill_readdir (fd_t *fd, DIR *dir, off_t off, size_t size,
                 if (this_size + filled > size) {
                         seekdir (dir, in_case);
 #ifndef GF_LINUX_HOST_OS
-                        if (telldir(dir) != (long)in_case &&
+                        if ((u_long)telldir(dir) != in_case &&
                             in_case != pfd->dir_eof) {
                                 gf_log (THIS->name, GF_LOG_ERROR,
-                                        "seekdir(%ld) failed on dir=%p: "
+                                        "seekdir(0x%llx) failed on dir=%p: "
                                         "Invalid argument (offset reused from "
                                         "another DIR * structure?)",
-                                        (long)in_case, dir);
+                                        in_case, dir);
                                 errno = EINVAL;
                                 count = -1;
                                 goto out;
@@ -4984,7 +4985,14 @@ posix_fill_readdir (fd_t *fd, DIR *dir, off_t off, size_t size,
                                 entry->d_name, strerror (errno));
                         goto out;
                 }
-                this_entry->d_off = telldir (dir);
+                /*
+                 * we store the offset of next entry here, which is
+                 * probably not intended, but code using syncop_readdir()
+                 * (glfs-heal.c, afr-self-heald.c, pump.c) rely on it
+                 * for directory read resumption.
+                 */
+                last_off = (u_long)telldir(dir);
+                this_entry->d_off = last_off;
                 this_entry->d_ino = entry->d_ino;
                 this_entry->d_type = entry->d_type;
 
@@ -4998,7 +5006,7 @@ posix_fill_readdir (fd_t *fd, DIR *dir, off_t off, size_t size,
                 /* Indicate EOF */
                 errno = ENOENT;
                 /* Remember EOF offset for later detection */
-                pfd->dir_eof = telldir (dir);
+                pfd->dir_eof = (u_long)last_off;
         }
 out:
         return count;