1 /* 2 * getsectsize.c --- get the sector size of a device. 3 * 4 * Copyright (C) 1995, 1995 Theodore Ts'o. 5 * Copyright (C) 2003 VMware, Inc. 6 * 7 * %Begin-Header% 8 * This file may be redistributed under the terms of the GNU Library 9 * General Public License, version 2. 10 * %End-Header% 11 */ 12 13 #define _LARGEFILE_SOURCE 14 #define _LARGEFILE64_SOURCE 15 16 #include <stdio.h> 17 #if HAVE_UNISTD_H 18 #include <unistd.h> 19 #endif 20 #if HAVE_ERRNO_H 21 #include <errno.h> 22 #endif 23 #include <fcntl.h> 24 #ifdef HAVE_LINUX_FD_H 25 #include <sys/ioctl.h> 26 #include <linux/fd.h> 27 #endif 28 29 #if defined(__linux__) && defined(_IO) 30 #if !defined(BLKSSZGET) 31 #define BLKSSZGET _IO(0x12,104)/* get block device sector size */ 32 #endif 33 #if !defined(BLKPBSZGET) 34 #define BLKPBSZGET _IO(0x12,123)/* get block physical sector size */ 35 #endif 36 #endif 37 38 #include "ext2_fs.h" 39 #include "ext2fs.h" 40 41 /* 42 * Returns the logical sector size of a device 43 */ 44 errcode_t ext2fs_get_device_sectsize(const char *file, int *sectsize) 45 { 46 int fd; 47 48 fd = ext2fs_open_file(file, O_RDONLY, 0); 49 if (fd < 0) 50 return errno; 51 52 #ifdef BLKSSZGET 53 if (ioctl(fd, BLKSSZGET, sectsize) >= 0) { 54 close(fd); 55 return 0; 56 } 57 #endif 58 *sectsize = 0; 59 close(fd); 60 return 0; 61 } 62 63 /* 64 * Return desired alignment for direct I/O 65 */ 66 int ext2fs_get_dio_alignment(int fd) 67 { 68 int align = 0; 69 70 #ifdef BLKSSZGET 71 if (ioctl(fd, BLKSSZGET, &align) < 0) 72 align = 0; 73 #endif 74 75 #ifdef _SC_PAGESIZE 76 if (align <= 0) 77 align = sysconf(_SC_PAGESIZE); 78 #endif 79 #ifdef HAVE_GETPAGESIZE 80 if (align <= 0) 81 align = getpagesize(); 82 #endif 83 if (align <= 0) 84 align = 4096; 85 86 return align; 87 } 88 89 /* 90 * Returns the physical sector size of a device 91 */ 92 errcode_t ext2fs_get_device_phys_sectsize(const char *file, int *sectsize) 93 { 94 int fd; 95 96 fd = ext2fs_open_file(file, O_RDONLY, 0); 97 if (fd < 0) 98 return errno; 99 100 #ifdef BLKPBSZGET 101 if (ioctl(fd, BLKPBSZGET, sectsize) >= 0) { 102 close(fd); 103 return 0; 104 } 105 #endif 106 *sectsize = 0; 107 close(fd); 108 return 0; 109 } 110
