From 2d6528fe90e6876f6d06abc7bdebc64a5f3ba0cc Mon Sep 17 00:00:00 2001
From: Andrea Mazzoleni <amadvance@users.sourceforge.net>
Date: Sun, 4 Nov 2012 00:26:30 +0100
Subject: [PATCH] If O_NOATIME use fails with EPERM, retry without it.

---
 check.c    |  2 +-
 handle.c   | 16 +++++++++-------
 parity.c   |  6 ++++--
 portable.h | 15 +++++++++++----
 4 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/check.c b/check.c
index 37967b91..06531c4c 100644
--- a/check.c
+++ b/check.c
@@ -1002,7 +1002,7 @@ static int state_check_process(struct snapraid_state* state, int check, int fix,
 				}
 
 				/* create it */
-				/* do not follow links to ensure to open the real file */
+				/* O_NOFOLLOW: do not follow links to ensure to open the real file */
 				f = open(path, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_NOFOLLOW, 0600);
 				if (f == -1) {
 					fprintf(stderr, "Error creating empty file '%s'. %s.\n", path, strerror(errno));
diff --git a/handle.c b/handle.c
index aaa5d07f..46bbf9ee 100644
--- a/handle.c
+++ b/handle.c
@@ -80,14 +80,15 @@ int handle_create(struct snapraid_handle* handle, struct snapraid_file* file)
 		return -1;
 	}
 
-	/* opening in sequential mode in Windows */
-	/* do not follow links to ensure to open the real file */
+	/* open for read write */
+	/* O_SEQUENTIAL: opening in sequential mode in Windows */
+	/* O_NOFOLLOW: do not follow links to ensure to open the real file */
 	handle->f = open(handle->path, O_RDWR | O_CREAT | O_BINARY | O_SEQUENTIAL | O_NOFOLLOW, 0600);
 
 	/* if failed for missing permission */
 	if (handle->f == -1 && errno == EACCES) {
 		/* retry without requesting write permission */
-		handle->f = open(handle->path, O_RDONLY | O_BINARY | O_SEQUENTIAL | O_NOFOLLOW | O_NOATIME);
+		handle->f = open(handle->path, O_RDONLY | O_BINARY | O_SEQUENTIAL | O_NOFOLLOW);
 	}
 
 	if (handle->f == -1) {
@@ -158,11 +159,12 @@ int handle_open(struct snapraid_handle* handle, struct snapraid_file* file)
 	}
 
 	pathprint(handle->path, sizeof(handle->path), "%s%s", handle->disk->dir, file->sub);
-	
-	/* opening in sequential mode in Windows */
-	/* do not follow links to ensure to open the real file */
-	handle->f = open(handle->path, O_RDONLY | O_BINARY | O_SEQUENTIAL | O_NOFOLLOW | O_NOATIME);
 
+	/* open for read */
+	/* O_SEQUENTIAL: opening in sequential mode in Windows */
+	/* O_NOFOLLOW: do not follow links to ensure to open the real file */
+	/* O_NOATIME: do not change access time */
+	handle->f = open_noatime(handle->path, O_RDONLY | O_BINARY | O_SEQUENTIAL | O_NOFOLLOW);
 	if (handle->f == -1) {
 		/* invalidate for error */
 		handle->file = 0;
diff --git a/parity.c b/parity.c
index a0e3e89f..2c84aad7 100644
--- a/parity.c
+++ b/parity.c
@@ -221,8 +221,10 @@ int parity_open(struct snapraid_parity* parity, const char* path)
 
 	pathcpy(parity->path, sizeof(parity->path), path);
 
-	/* opening in sequential mode in Windows */
-	parity->f = open(parity->path, O_RDONLY | O_BINARY | O_SEQUENTIAL | O_NOATIME);
+	/* open for read */
+	/* O_SEQUENTIAL: opening in sequential mode in Windows */
+	/* O_NOATIME: do not change access time */
+	parity->f = open_noatime(parity->path, O_RDONLY | O_BINARY | O_SEQUENTIAL);
 	if (parity->f == -1) {
 		fprintf(stderr, "Error opening parity file '%s'. %s.\n", parity->path, strerror(errno));
 		return -1;
diff --git a/portable.h b/portable.h
index 31927634..b6fdded2 100644
--- a/portable.h
+++ b/portable.h
@@ -137,12 +137,19 @@
 #define STAT_NSEC(st) -1
 #endif
 
+#ifdef O_NOATIME
 /**
- * Defines O_NOATIME if absent.
- * O_NOATIME is used to open files in RDONLY mode avoding to update their access time.
+ * Open a file with the O_NOATIME flag to avoid to update the acces time.
  */
-#ifndef O_NOATIME
-#define O_NOATIME 0
+static int open_noatime(const char* file, int flags)
+{
+	int f = open(file, flags | O_NOATIME);
+	if (f == -1 && errno == EPERM)
+		f = open(file, flags);
+	return f;
+}
+#else
+#define open_noatime open 
 #endif
 
 /**