diff --git a/fileio.c b/fileio.c

index b183e20..72d6076 100644

--- a/fileio.c

+++ b/fileio.c

@@ -34,6 +34,7 @@

 #define ALIGNED_LENGTH(len) ((((len) - 1) | (ALIGN_BOUNDRY-1)) + 1)

 extern int sparse_files;

+extern int sparse_files_block_size;

 OFF_T preallocated_len = 0;

@@ -147,7 +148,7 @@ int write_file(int f, int use_seek, OFF_T offset, const char *buf, int len)

 	while (len > 0) {

 		int r1;

 		if (sparse_files > 0) {

-			int len1 = MIN(len, SPARSE_WRITE_SIZE);

+			int len1 = MIN(len, sparse_files_block_size ? sparse_files_block_size : SPARSE_WRITE_SIZE);

 			r1 = write_sparse(f, use_seek, offset, buf, len1);

 			offset += r1;

 		} else {

diff --git a/options.c b/options.c

index 195672e..d08c05a 100644

--- a/options.c

+++ b/options.c

@@ -76,6 +76,7 @@ int remove_source_files = 0;

 int one_file_system = 0;

 int protocol_version = PROTOCOL_VERSION;

 int sparse_files = 0;

+long sparse_files_block_size = 0;

 int preallocate_files = 0;

 int do_compression = 0;

 int def_compress_level = NOT_SPECIFIED;

@@ -717,6 +718,7 @@ void usage(enum logcode F)

   rprintf(F,"     --fake-super            store/recover privileged attrs using xattrs\n");

 #endif

   rprintf(F," -S, --sparse                turn sequences of nulls into sparse blocks\n");

+  rprintf(F,"     --sparse-block=SIZE     set block size used to handle sparse files\n");

 #ifdef SUPPORT_PREALLOCATION

   rprintf(F,"     --preallocate           allocate dest files before writing them\n");

 #else

@@ -927,6 +929,7 @@ static struct poptOption long_options[] = {

   {"sparse",          'S', POPT_ARG_VAL,    &sparse_files, 1, 0, 0 },

   {"no-sparse",        0,  POPT_ARG_VAL,    &sparse_files, 0, 0, 0 },

   {"no-S",             0,  POPT_ARG_VAL,    &sparse_files, 0, 0, 0 },

+  {"sparse-block",     0,  POPT_ARG_LONG,   &sparse_files_block_size, 0, 0, 0 },

   {"preallocate",      0,  POPT_ARG_NONE,   &preallocate_files, 0, 0, 0},

   {"inplace",          0,  POPT_ARG_VAL,    &inplace, 1, 0, 0 },

   {"no-inplace",       0,  POPT_ARG_VAL,    &inplace, 0, 0, 0 },

diff --git a/options.c b/options.c

index b12da55..5a27452 100644

--- a/options.c

+++ b/options.c

@@ -2606,6 +2606,12 @@ void server_options(char **args, int *argc_p)

 		args[ac++] = arg;

 	}

+	if (sparse_files_block_size) {

+		if (asprintf(&arg, "--sparse-block=%lu", sparse_files_block_size) < 0)

+			goto oom;

+		args[ac++] = arg;

+	}

+

 	if (io_timeout) {

 		if (asprintf(&arg, "--timeout=%d", io_timeout) < 0)

 			goto oom;

diff --git a/rsync.yo b/rsync.yo

--- a/rsync.yo

+++ b/rsync.yo

@@ -377,6 +377,7 @@ to the detailed description below for a complete description.  verb(

      --super                 receiver attempts super-user activities

      --fake-super            store/recover privileged attrs using xattrs

  -S, --sparse                turn sequences of nulls into sparse blocks

+     --sparse-block=SIZE     set block size used to handle sparse files

      --preallocate           allocate dest files before writing

  -n, --dry-run               perform a trial run with no changes made

  -W, --whole-file            copy files whole (w/o delta-xfer algorithm)

@@ -1299,6 +1300,15 @@ If combined with bf(--sparse), the file will only have sparse blocks (as

 opposed to allocated sequences of null bytes) if the kernel version and

 filesystem type support creating holes in the allocated data.

+dit(bf(--sparse-block=SIZE)) Change the block size used to handle sparse files

+to SIZE bytes.  This option only has an effect if the bf(--sparse) (bf(-S))

+option was also specified.  The default block size used by rsync to detect a

+file hole is 1024 bytes; when the receiver writes data to the destination file

+and option bf(--sparse) is used, rsync checks every 1024-bytes chunk to detect

+if they are actually filled with data or not.  With certain filesystems,

+optimized to receive data streams for example, enlarging this block size can

+strongly increase performance.  The option can be used to tune this block size.

+

 dit(bf(-n, --dry-run)) This makes rsync perform a trial run that doesn't

 make any changes (and produces mostly the same output as a real run).  It

 is most commonly used in combination with the bf(-v, --verbose) and/or

diff --git a/rsync.1 b/rsync.1

index 855dd47..1d7af3c 100644

--- a/rsync.1

+++ b/rsync.1

@@ -454,6 +454,7 @@ to the detailed description below for a complete description.

      \-\-super                 receiver attempts super\-user activities

      \-\-fake\-super            store/recover privileged attrs using xattrs

  \-S, \-\-sparse                turn sequences of nulls into sparse blocks

+     \-\-sparse-block=SIZE      set block size used to handle sparse files

      \-\-preallocate           allocate dest files before writing

  \-n, \-\-dry\-run               perform a trial run with no changes made

  \-W, \-\-whole\-file            copy files whole (w/o delta\-xfer algorithm)

@@ -1493,6 +1493,16 @@ If combined with \fB\-\-sparse\fP, the file will only have sparse blocks (as

 opposed to allocated sequences of null bytes) if the kernel version and

 filesystem type support creating holes in the allocated data.

 .IP 

+.IP "\fB\-\-sparse\-block=SIZE\fP"

+Change the block size used to handle sparse files

+to SIZE bytes.  This option only has an effect if the \fB\-\-sparse\fP (\fB\-S\fP)

+option was also specified.  The default block size used by rsync to detect a

+file hole is 1024 bytes; when the receiver writes data to the destination file

+and option \fB\-\-sparse\fP is used, rsync checks every 1024\-bytes chunk to detect

+if they are actually filled with data or not.  With certain filesystems,

+optimized to receive data streams for example, enlarging this block size can

+strongly increase performance.  The option can be used to tune this block size.

+.IP

 .IP "\fB\-n, \-\-dry\-run\fP"

 This makes rsync perform a trial run that doesn\(cq\&t

 make any changes (and produces mostly the same output as a real run).  It