From dd0880b8ee67f9a69802a2a3ef26cd5df6881129 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Mon, 24 Feb 2020 14:13:01 +0100
Subject: [SERVER] Introduce ignoreAllocErrors

If enabled, a failed fallocate will not abort image replication, but
retry with sparse mode.
---
 src/server/globals.c | 3 +++
 src/server/globals.h | 6 ++++++
 src/server/image.c   | 9 +++++++--
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/server/globals.c b/src/server/globals.c
index f8c3f66..2e87400 100644
--- a/src/server/globals.c
+++ b/src/server/globals.c
@@ -21,6 +21,7 @@ atomic_int _backgroundReplication = BGR_FULL;
 atomic_int _bgrMinClients = 0;
 atomic_bool _lookupMissingForProxy = true;
 atomic_bool _sparseFiles = false;
+atomic_bool _ignoreAllocErrors = false;
 atomic_bool _removeMissingImages = true;
 atomic_int _uplinkTimeout = SOCKET_TIMEOUT_UPLINK;
 atomic_int _clientTimeout = SOCKET_TIMEOUT_CLIENT;
@@ -75,6 +76,7 @@ static int ini_handler(void *custom UNUSED, const char* section, const char* key
 	SAVE_TO_VAR_INT( dnbd3, bgrMinClients );
 	SAVE_TO_VAR_BOOL( dnbd3, lookupMissingForProxy );
 	SAVE_TO_VAR_BOOL( dnbd3, sparseFiles );
+	SAVE_TO_VAR_BOOL( dnbd3, ignoreAllocErrors );
 	SAVE_TO_VAR_BOOL( dnbd3, removeMissingImages );
 	SAVE_TO_VAR_BOOL( dnbd3, closeUnusedFd );
 	SAVE_TO_VAR_UINT( dnbd3, serverPenalty );
@@ -322,6 +324,7 @@ size_t globals_dumpConfig(char *buffer, size_t size)
 	PINT(bgrMinClients);
 	PBOOL(lookupMissingForProxy);
 	PBOOL(sparseFiles);
+	PBOOL(ignoreAllocErrors);
 	PBOOL(removeMissingImages);
 	PINT(uplinkTimeout);
 	PINT(clientTimeout);
diff --git a/src/server/globals.h b/src/server/globals.h
index df8c595..b1336dc 100644
--- a/src/server/globals.h
+++ b/src/server/globals.h
@@ -254,6 +254,12 @@ extern atomic_bool _lookupMissingForProxy;
  */
 extern atomic_bool _sparseFiles;
 
+/**
+ * If true, don't abort image replication if preallocating
+ * the image fails, but retry with sparse file.
+ */
+extern atomic_bool _ignoreAllocErrors;
+
 /**
  * Port to listen on (default: #define PORT (5003))
  */
diff --git a/src/server/image.c b/src/server/image.c
index 16dae45..6017e59 100644
--- a/src/server/image.c
+++ b/src/server/image.c
@@ -1111,14 +1111,19 @@ bool image_create(char *image, int revision, uint64_t size)
 		logadd( LOG_DEBUG1, "Could not allocate %d bytes for %s (errno=%d)", mapsize, cache, err );
 	}
 	// Now write image
+	bool fallback = false;
 	if ( !_sparseFiles && !file_alloc( fdImage, 0, size ) ) {
 		logadd( LOG_ERROR, "Could not allocate %" PRIu64 " bytes for %s (errno=%d)", size, path, errno );
 		logadd( LOG_ERROR, "It is highly recommended to use a file system that supports preallocating disk"
 				" space without actually writing all zeroes to the block device." );
 		logadd( LOG_ERROR, "If you cannot fix this, try setting sparseFiles=true, but don't expect"
 				" divine performance during replication." );
-		goto failure_cleanup;
-	} else if ( _sparseFiles && !file_setSize( fdImage, size ) ) {
+		if ( !_ignoreAllocErrors ) {
+			goto failure_cleanup;
+		}
+		fallback = true;
+	}
+	if ( ( _sparseFiles || fallback ) && !file_setSize( fdImage, size ) ) {
 		logadd( LOG_ERROR, "Could not create sparse file of %" PRIu64 " bytes for %s (errno=%d)", size, path, errno );
 		logadd( LOG_ERROR, "Make sure you have enough disk space, check directory permissions, fs errors etc." );
 		goto failure_cleanup;
-- 
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