Few synchronization and alignment related fixes

1 files changed, 38 insertions, 13 deletions

diff --git a/default.c b/default.c
index 8ff5135..02b9f6a 100644
--- a/default.c
+++ b/default.c
@@ -40,6 +40,8 @@
 
 typedef struct {
     int fd;
+
+    int sync_mode;
     
     size_t prior_size;		/**< original size of file */
     size_t preallocated;	/**< preallocated bytes */
@@ -56,9 +58,6 @@ int fastwriter_default_open(fastwriter_t *fw, const char *name, fastwriter_flags
     int open_flags = (O_CREAT|O_WRONLY|O_NOATIME|O_LARGEFILE);
     int open_mode = (S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
 
-#ifdef SYNC_MODE
-    open_flags |= O_DIRECT;//|O_SYNC;
-#endif /* SYNC_MODE */
     
     fastwriter_default_t *ctx;
 
@@ -72,9 +71,17 @@ int fastwriter_default_open(fastwriter_t *fw, const char *name, fastwriter_flags
 
     fw->ctx = ctx;
 
+#ifdef SYNC_MODE
+    open_flags |= O_DIRECT;
+    ctx->sync_mode = 1;
+#endif /* SYNC_MODE */
+
+    ctx->prior_size = 0;
+
     if (!strcmp(fs, "raw")) {
 	ctx->wr_block = EXT4_WRITEBLOCK;
 	ctx->pa_block = 0;
+	ctx->prior_size = (size_t)-1;
     } else if (!strcmp(fs, "ext4")) {
 	ctx->wr_block = EXT4_WRITEBLOCK;
 	ctx->pa_block = EXT4_PREALLOCATE;
@@ -95,13 +102,21 @@ int fastwriter_default_open(fastwriter_t *fw, const char *name, fastwriter_flags
     ctx->fd = open(name, open_flags, open_mode);
     if (ctx->fd < 0) return errno;
 
-    ctx->prior_size = 0;
-    
-#ifndef HAVE_LINUX_FALLOC_H
     if (((open_flags&FASTWRITER_FLAGS_OVERWRITE)==0)&&(strcmp(fs, "raw"))) {
 	ctx->prior_size = lseek(ctx->fd, 0, SEEK_END);
+# ifdef SYNC_MODE	
+	if (ctx->prior_size%FASTWRITER_SYNCIO_ALIGN) {
+	    close(ctx->fd);
+	    
+	    ctx->fd = open(name, open_flags&~O_DIRECT, open_mode);
+	    if (ctx->fd < 0) return errno;
+	    
+	    ctx->prior_size = lseek(ctx->fd, 0, SEEK_END);
+	    
+	    ctx->sync_mode = 0;
+	}
+# endif /* SYNC_MODE */
     }
-#endif /* HAVE_LINUX_FALLOC_H */
 
     ctx->preallocated = 0;
 
@@ -114,11 +129,11 @@ void fastwriter_default_close(fastwriter_t *fw) {
 	fastwriter_default_t *ctx = (fastwriter_default_t*)fw->ctx;
 
 	if (ctx->fd >= 0) {
-#ifndef HAVE_LINUX_FALLOC_H
-	    if (ctx->prior_size) {
-		ftrucate(ctx->fd, ctx->prior_size + fw->written);
+#if defined(SYNC_MODE)||!defined(HAVE_LINUX_FALLOC_H)
+	    if (ctx->prior_size != (size_t)-1) {
+		ftruncate(ctx->fd, ctx->prior_size + fw->written);
 	    }
-#endif /* HAVE_LINUX_FALLOC_H */
+#endif
 	    close(ctx->fd);
 	}
 	
@@ -130,9 +145,10 @@ void fastwriter_default_close(fastwriter_t *fw) {
 
 int fastwriter_default_write(fastwriter_t *fw, fastwriter_write_flags_t flags, size_t size, void *data, size_t *written) {
     size_t sum = 0;
+    size_t delta = 0;
     ssize_t res;
     fastwriter_default_t *ctx = (fastwriter_default_t*)fw->ctx;
-    
+
     if ((flags&FASTWRITER_WRITE_FLAG_FORCE)==0) {
 	if (size < ctx->wr_block) {
 	    *written = 0;
@@ -141,6 +157,7 @@ int fastwriter_default_write(fastwriter_t *fw, fastwriter_write_flags_t flags, s
     
         size -= size % ctx->wr_block;
     }
+    
 
     if ((ctx->pa_block)&&((fw->written + size) > ctx->preallocated)) {
 #ifdef HAVE_LINUX_FALLOC_H
@@ -153,9 +170,17 @@ int fastwriter_default_write(fastwriter_t *fw, fastwriter_write_flags_t flags, s
 	    ctx->preallocated += ctx->pa_block;
 	}
     }
+
+#ifdef SYNC_MODE
+	// we expect this to happen only at last iteration (buffer is multiply of the required align)
+    if ((ctx->sync_mode)&&(size%FASTWRITER_SYNCIO_ALIGN)) {
+	delta = FASTWRITER_SYNCIO_ALIGN - size%FASTWRITER_SYNCIO_ALIGN;
+    }
+#endif /* SYNC_MODE */
     
     do {
-	res = write(ctx->fd, data, size);
+	res = write(ctx->fd, data + sum, size + delta - sum);
+//	printf("%i %i %p %zu %i\n", res, ctx->fd, data, size, delta);
 	if (res < 0) {
 	    *written = sum;
 	    return errno;