Added call out to a Linux-compatible fallocate() when we need to extend a file

allocation extent without changing end-of-file size.

Autobuild-User: Jeremy Allison <jra@samba.org>
Autobuild-Date: Tue Dec 21 02:41:24 CET 2010 on sn-devel-104

5 files changed, 86 insertions, 3 deletions

diff --git a/source3/configure.in b/source3/configure.in
index b43d0b34de..ed99b17191 100644
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -741,6 +741,7 @@ AC_CHECK_HEADERS(sys/syslog.h syslog.h)
 AC_CHECK_HEADERS(langinfo.h locale.h)
 AC_CHECK_HEADERS(xfs/libxfs.h)
 AC_CHECK_HEADERS(netgroup.h)
+AC_CHECK_HEADERS(linux/falloc.h)
 
 AC_CHECK_HEADERS(rpcsvc/yp_prot.h,,,[[
 #if HAVE_RPC_RPC_H
@@ -1095,6 +1096,7 @@ AC_CHECK_FUNCS(sigprocmask sigblock sigaction sigset innetgr setnetgrent getnetg
 AC_CHECK_FUNCS(initgroups select poll rdchk getgrnam getgrent pathconf)
 AC_CHECK_FUNCS(setpriv setgidx setuidx setgroups sysconf stat64 fstat64)
 AC_CHECK_FUNCS(lstat64 fopen64 atexit grantpt lseek64 ftruncate64 posix_fallocate posix_fallocate64)
+AC_CHECK_FUNCS(fallocate fallocate64)
 AC_CHECK_FUNCS(fseek64 fseeko64 ftell64 ftello64 setluid getpwanam)
 AC_CHECK_FUNCS(opendir64 readdir64 seekdir64 telldir64 rewinddir64 closedir64)
 AC_CHECK_FUNCS(getpwent_r)
@@ -2563,6 +2565,39 @@ fi
 fi
 # end utmp details
 
+AC_CACHE_CHECK([for linux fallocate],samba_cv_HAVE_LINUX_FALLOCATE,[
+AC_TRY_COMPILE([
+#if defined(HAVE_UNISTD_H)
+#include <unistd.h>
+#endif
+#include <sys/types.h>
+#define _GNU_SOURCE
+#include <fcntl.h>
+#if defined(HAVE_LINUX_FALLOC_H)
+#include <linux/falloc.h>
+#endif],
+[int ret = fallocate(0, FALLOC_FL_KEEP_SIZE, 0, 10);],
+samba_cv_HAVE_LINUX_FALLOCATE=yes,samba_cv_HAVE_LINUX_FALLOCATE=no)])
+if test x"$samba_cv_HAVE_LINUX_FALLOCATE" = x"yes" && test x"$ac_cv_func_fallocate" = x"yes"; then
+    AC_DEFINE(HAVE_LINUX_FALLOCATE,1,[Whether the Linux 'fallocate' function is available])
+fi
+
+AC_CACHE_CHECK([for linux fallocate64],samba_cv_HAVE_LINUX_FALLOCATE64,[
+AC_TRY_COMPILE([
+#if defined(HAVE_UNISTD_H)
+#include <unistd.h>
+#endif
+#include <sys/types.h>
+#define _GNU_SOURCE
+#include <fcntl.h>
+#if defined(HAVE_LINUX_FALLOC_H)
+#include <linux/falloc.h>
+#endif],
+[int ret = fallocate64(0, FALLOC_FL_KEEP_SIZE, 0, 10);],
+samba_cv_HAVE_LINUX_FALLOCATE64=yes,samba_cv_HAVE_LINUX_FALLOCATE64=no)])
+if test x"$samba_cv_HAVE_LINUX_FALLOCATE64" = x"yes" && test x"$ac_cv_func_fallocate64" = x"yes"; then
+    AC_DEFINE(HAVE_LINUX_FALLOCATE64,1,[Whether the Linux 'fallocate64' function is available])
+fi
 
 ICONV_LOOK_DIRS="/usr /usr/local /sw /opt"
 AC_ARG_WITH(libiconv,
diff --git a/source3/include/proto.h b/source3/include/proto.h
index dabb315875..566b3f31df 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -888,6 +888,7 @@ int sys_lstat(const char *fname,SMB_STRUCT_STAT *sbuf,
 	      bool fake_dir_create_times);
 int sys_ftruncate(int fd, SMB_OFF_T offset);
 int sys_posix_fallocate(int fd, SMB_OFF_T offset, SMB_OFF_T len);
+int sys_fallocate(int fd, enum vfs_fallocate_mode mode, SMB_OFF_T offset, SMB_OFF_T len);
 SMB_OFF_T sys_lseek(int fd, SMB_OFF_T offset, int whence);
 int sys_fseek(FILE *fp, SMB_OFF_T offset, int whence);
 SMB_OFF_T sys_ftell(FILE *fp);
diff --git a/source3/lib/system.c b/source3/lib/system.c
index 02322b72b5..4cf6a299da 100644
--- a/source3/lib/system.c
+++ b/source3/lib/system.c
@@ -695,6 +695,41 @@ int sys_posix_fallocate(int fd, SMB_OFF_T offset, SMB_OFF_T len)
 }
 
 /*******************************************************************
+ An fallocate() function that matches the semantics of the Linux one.
+********************************************************************/
+
+#ifdef HAVE_LINUX_FALLOC_H
+#include <linux/falloc.h>
+#endif
+
+int sys_fallocate(int fd, enum vfs_fallocate_mode mode, SMB_OFF_T offset, SMB_OFF_T len)
+{
+#if defined(HAVE_LINUX_FALLOCATE64) || defined(HAVE_LINUX_FALLOCATE)
+	int lmode;
+	switch (mode) {
+	case VFS_FALLOCATE_EXTEND_SIZE:
+		lmode = 0;
+		break;
+	case VFS_FALLOCATE_KEEP_SIZE:
+		lmode = FALLOC_FL_KEEP_SIZE;
+		break;
+	default:
+		errno = EINVAL;
+		return -1;
+	}
+#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OFF64_T) && defined(HAVE_LINUX_FALLOCATE64)
+	return fallocate64(fd, lmode, offset, len);
+#elif defined(HAVE_LINUX_FALLOCATE)
+	return fallocate(fd, lmode, offset, len);
+#endif
+#else
+	/* TODO - plumb in fallocate from other filesysetms like VXFS etc. JRA. */
+	errno = ENOSYS;
+	return -1;
+#endif
+}
+
+/*******************************************************************
  An ftruncate() wrapper that will deal with 64 bit filesizes.
 ********************************************************************/
 
diff --git a/source3/modules/vfs_default.c b/source3/modules/vfs_default.c
index e08d48ff5f..54f38c3714 100644
--- a/source3/modules/vfs_default.c
+++ b/source3/modules/vfs_default.c
@@ -965,9 +965,10 @@ static int vfswrap_fallocate(vfs_handle_struct *handle,
 	START_PROFILE(syscall_fallocate);
 	if (mode == VFS_FALLOCATE_EXTEND_SIZE) {
 		result = sys_posix_fallocate(fsp->fh->fd, offset, len);
+	} else if (mode == VFS_FALLOCATE_KEEP_SIZE) {
+		result = sys_fallocate(fsp->fh->fd, mode, offset, len);
 	} else {
-		/* TODO - implement call into Linux fallocate call. */
-		errno = ENOSYS;
+		errno = EINVAL;
 		result = -1;
 	}
 	END_PROFILE(syscall_fallocate);
diff --git a/source3/smbd/vfs.c b/source3/smbd/vfs.c
index 2ebe2a1062..802639f2fb 100644
--- a/source3/smbd/vfs.c
+++ b/source3/smbd/vfs.c
@@ -501,13 +501,24 @@ int vfs_allocate_file_space(files_struct *fsp, uint64_t len)
 		return ret;
 	}
 
+	if (!lp_strict_allocate(SNUM(fsp->conn)))
+		return 0;
+
 	/* Grow - we need to test if we have enough space. */
 
 	contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_ALLOC_GROW);
+
+	/* See if we have a syscall that will allocate beyond end-of-file
+	   without changing EOF. */
+	ret = SMB_VFS_FALLOCATE(fsp, VFS_FALLOCATE_KEEP_SIZE, 0, len);
+
 	contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_ALLOC_GROW);
 
-	if (!lp_strict_allocate(SNUM(fsp->conn)))
+	if (ret == 0) {
+		/* We changed the allocation size on disk, but not
+		   EOF - exactly as required. We're done ! */
 		return 0;
+	}
 
 	len -= fsp->fsp_name->st.st_ex_size;
 	len /= 1024; /* Len is now number of 1k blocks needed. */