Provided support for big writes

include/fuse-lite/fuse_common.h

@@ -43,6 +43,8 @@ extern "C" {
 #define FUSE_CAP_DONT_MASK	(1 << 6)
 #endif
 
+#define FUSE_CAP_BIG_WRITES	(1 << 5)
+
 /**
  * Information about open files
  *
@@ -116,19 +118,12 @@ struct fuse_conn_info {
 	 */
 	unsigned max_readahead;
 
-#ifdef POSIXACLS
 	unsigned capable;
 	unsigned want;
 	/**
 	 * For future use.
 	 */
 	unsigned reserved[25];
-#else
-	/**
-	 * For future use.
-	 */
-	unsigned reserved[27];
-#endif
     };
 
 struct fuse_session;

include/fuse-lite/fuse_kernel.h

@@ -130,10 +130,12 @@ struct fuse_file_lock {
 
 /**
  * INIT request/reply flags
+ * FUSE_BIG_WRITES: allow big writes to be issued to the file system
  * FUSE_DONT_MASK: don't apply umask to file mode on create operations
  */
 #define FUSE_ASYNC_READ		(1 << 0)
 #define FUSE_POSIX_LOCKS	(1 << 1)
+#define FUSE_BIG_WRITES		(1 << 5)
 #define FUSE_DONT_MASK		(1 << 6)
 
 /**

include/ntfs-3g/param.h

@@ -50,6 +50,19 @@ enum {
 	/* maximum cluster size for allowing compression for new files */
 #define MAX_COMPRESSION_CLUSTER_SIZE 4096
 
+/*
+ *		Use of big write buffers
+ *
+ *	With small volumes, the cluster allocator may fail to allocate
+ *	enough clusters when the volume is nearly full. At most a run
+ *	can be allocated per bitmap chunk. So, there is a danger when the
+ *	number of chunks (capacity/(32768*clsiz)) is less than the number
+ *	of clusters in the biggest write buffer (131072/clsiz). Hence
+ *	a safe minimal capacity is 4GB
+ */
+
+#define SAFE_CAPACITY_FOR_BIG_WRITES 0x100000000LL
+
 /*
  *		Parameters for runlists
  */

libfuse-lite/fuse_lowlevel.c

@@ -1043,6 +1043,8 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
 	if (arg->flags & FUSE_DONT_MASK)
 	    f->conn.capable |= FUSE_CAP_DONT_MASK;
 #endif
+	if (arg->flags & FUSE_BIG_WRITES)
+	    f->conn.capable |= FUSE_CAP_BIG_WRITES;
     } else {
         f->conn.async_read = 0;
         f->conn.max_readahead = 0;
@@ -1087,6 +1089,8 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
     if (f->conn.want & FUSE_CAP_DONT_MASK)
 	outarg.flags |= FUSE_DONT_MASK;
 #endif
+    if (f->conn.want & FUSE_CAP_BIG_WRITES)
+	outarg.flags |= FUSE_BIG_WRITES;
     outarg.max_readahead = f->conn.max_readahead;
     outarg.max_write = f->conn.max_write;
 

src/lowntfs-3g.c

@@ -557,7 +557,8 @@ int ntfs_macfuse_setchgtime(const char *path, const struct timespec *tv)
 }
 #endif /* defined(__APPLE__) || defined(__DARWIN__) */
 
-#if defined(FUSE_CAP_DONT_MASK) || (defined(__APPLE__) || defined(__DARWIN__))
+#if defined(FUSE_CAP_DONT_MASK) || defined(FUSE_CAP_BIG_WRITES) \
+		|| (defined(__APPLE__) || defined(__DARWIN__))
 static void ntfs_init(void *userdata __attribute__((unused)),
 			struct fuse_conn_info *conn)
 {
@@ -568,6 +569,12 @@ static void ntfs_init(void *userdata __attribute__((unused)),
 		/* request umask not to be enforced by fuse */
 	conn->want |= FUSE_CAP_DONT_MASK;
 #endif /* defined FUSE_CAP_DONT_MASK */
+#ifdef FUSE_CAP_BIG_WRITES
+	if (ctx->big_writes
+	    && ((ctx->vol->nr_clusters << ctx->vol->cluster_size_bits)
+			>= SAFE_CAPACITY_FOR_BIG_WRITES))
+		conn->want |= FUSE_CAP_BIG_WRITES;
+#endif
 }
 #endif /* defined(FUSE_CAP_DONT_MASK) || (defined(__APPLE__) || defined(__DARWIN__)) */
 
@@ -3364,7 +3371,8 @@ static struct fuse_lowlevel_ops ntfs_3g_ops = {
 	.setbkuptime	= ntfs_macfuse_setbkuptime,
 	.setchgtime	= ntfs_macfuse_setchgtime,
 #endif /* defined(__APPLE__) || defined(__DARWIN__) */
-#if defined(FUSE_CAP_DONT_MASK) || (defined(__APPLE__) || defined(__DARWIN__))
+#if defined(FUSE_CAP_DONT_MASK) || defined(FUSE_CAP_BIG_WRITES) \
+		|| (defined(__APPLE__) || defined(__DARWIN__))
 	.init		= ntfs_init
 #endif
 };

src/ntfs-3g.8.in

@@ -284,6 +284,11 @@ This option disables creating new transparently compressed files in directories
 marked for compression. Existing compressed files can still be read and
 updated. Currently this is the default option.
 .TP
+.B big_writes
+This option prevents fuse from splitting write buffers into 4K chunks,
+enabling big write buffers to be transferred from the application in a
+single step (up to some system limit, generally 128K bytes).
+.TP
 .B debug
 Makes ntfs-3g to print a lot of debug output from libntfs-3g and FUSE.
 .TP

src/ntfs-3g.c

@@ -635,7 +635,8 @@ int ntfs_macfuse_setchgtime(const char *path, const struct timespec *tv)
 }
 #endif /* defined(__APPLE__) || defined(__DARWIN__) */
 
-#if defined(FUSE_CAP_DONT_MASK) || (defined(__APPLE__) || defined(__DARWIN__))
+#if defined(FUSE_CAP_DONT_MASK) || defined(FUSE_CAP_BIG_WRITES) \
+		|| (defined(__APPLE__) || defined(__DARWIN__))
 static void *ntfs_init(struct fuse_conn_info *conn)
 {
 #if defined(__APPLE__) || defined(__DARWIN__)
@@ -645,6 +646,12 @@ static void *ntfs_init(struct fuse_conn_info *conn)
 		/* request umask not to be enforced by fuse */
 	conn->want |= FUSE_CAP_DONT_MASK;
 #endif /* defined FUSE_CAP_DONT_MASK */
+#ifdef FUSE_CAP_BIG_WRITES
+	if (ctx->big_writes
+	    && ((ctx->vol->nr_clusters << ctx->vol->cluster_size_bits)
+			>= SAFE_CAPACITY_FOR_BIG_WRITES))
+		conn->want |= FUSE_CAP_BIG_WRITES;
+#endif
 	return NULL;
 }
 #endif /* defined(FUSE_CAP_DONT_MASK) || (defined(__APPLE__) || defined(__DARWIN__)) */
@@ -3283,7 +3290,8 @@ static struct fuse_operations ntfs_3g_ops = {
 	.setbkuptime	= ntfs_macfuse_setbkuptime,
 	.setchgtime	= ntfs_macfuse_setchgtime,
 #endif /* defined(__APPLE__) || defined(__DARWIN__) */
-#if defined(FUSE_CAP_DONT_MASK) || (defined(__APPLE__) || defined(__DARWIN__))
+#if defined(FUSE_CAP_DONT_MASK) || defined(FUSE_CAP_BIG_WRITES) \
+		|| (defined(__APPLE__) || defined(__DARWIN__))
 	.init		= ntfs_init
 #endif
 };

src/ntfs-3g_common.c

@@ -99,6 +99,7 @@ const struct DEFOPTION optionlist[] = {
 	{ "norecover", OPT_NORECOVER, FLGOPT_BOGUS },
 	{ "remove_hiberfile", OPT_REMOVE_HIBERFILE, FLGOPT_BOGUS },
 	{ "sync", OPT_SYNC, FLGOPT_BOGUS | FLGOPT_APPEND },
+	{ "big_writes", OPT_BIG_WRITES, FLGOPT_BOGUS },
 	{ "locale", OPT_LOCALE, FLGOPT_STRING },
 	{ "nfconv", OPT_NFCONV, FLGOPT_BOGUS },
 	{ "nonfconv", OPT_NONFCONV, FLGOPT_BOGUS },
@@ -314,6 +315,11 @@ char *parse_mount_options(ntfs_fuse_context_t *ctx,
 			case OPT_SYNC :
 				ctx->sync = TRUE;
 				break;
+#ifdef FUSE_CAP_BIG_WRITES
+			case OPT_BIG_WRITES :
+				ctx->big_writes = TRUE;
+				break;
+#endif
 			case OPT_LOCALE :
 				ntfs_set_char_encoding(val);
 				break;

src/ntfs-3g_common.h

@@ -73,6 +73,7 @@ enum {
 	OPT_NORECOVER,
 	OPT_REMOVE_HIBERFILE,
 	OPT_SYNC,
+	OPT_BIG_WRITES,
 	OPT_LOCALE,
 	OPT_NFCONV,
 	OPT_NONFCONV,
@@ -127,6 +128,7 @@ typedef struct {
 	BOOL recover;
 	BOOL hiberfile;
 	BOOL sync;
+	BOOL big_writes;
 	BOOL debug;
 	BOOL no_detach;
 	BOOL blkdev;