[nginx] Writing to some file systems can be interrupted.

[Valentin Bartenev]

details:   http://hg.nginx.org/nginx/rev/6fce16b1fc10
branches:  
changeset: 6240:6fce16b1fc10
user:      Valentin Bartenev <vbart at nginx.com>
date:      Wed Sep 02 19:26:40 2015 +0300
description:
Writing to some file systems can be interrupted.

At least such behavior was observed with CephFS, see:
http://mailman.nginx.org/pipermail/nginx/2015-July/048188.html.

diffstat:

 src/os/unix/ngx_files.c |  13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

diffs (33 lines):

diff -r 281863981d0b -r 6fce16b1fc10 src/os/unix/ngx_files.c
--- a/src/os/unix/ngx_files.c	Mon Aug 31 23:26:33 2015 +0300
+++ b/src/os/unix/ngx_files.c	Wed Sep 02 19:26:40 2015 +0300
@@ -264,6 +264,7 @@ ngx_write_chain_to_file(ngx_file_t *file
     u_char        *prev;
     size_t         size;
     ssize_t        total, n;
+    ngx_err_t      err;
     ngx_array_t    vec;
     struct iovec  *iov, iovs[NGX_IOVS];
 
@@ -335,10 +336,20 @@ ngx_write_chain_to_file(ngx_file_t *file
             file->sys_offset = offset;
         }
 
+eintr:
+
         n = writev(file->fd, vec.elts, vec.nelts);
 
         if (n == -1) {
-            ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
+            err = ngx_errno;
+
+            if (err == NGX_EINTR) {
+                ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err,
+                               "writev() was interrupted");
+                goto eintr;
+            }
+
+            ngx_log_error(NGX_LOG_CRIT, file->log, err,
                           "writev() \"%s\" failed", file->name.data);
             return NGX_ERROR;
         }