Dear Mani, -> It depends upon the actual disk block size not the file system block size ..
I think that it always depends on the file-system block size. A disk block size will always less than or equal to File system block size. For example, say a FS X has block size 2K and disk block size =512. So, when you create a 1 byte file, file_size = 1byte and disk blocks =4. Now, if another FS Y has block size 4K and you create a 1 byte file then :- file_size = 1 byte and disk blocks= 8. On Mon, Aug 8, 2011 at 12:46 PM, mani <manish...@gmail.com> wrote: > The ls uses st_size while du uses st_blocks. > So > st_size "file size in bytes" > st_blocks "number of 512 byte blocks allocated". > It depends upon the actual disk block size not the file system block size > .. > try using the ls -ls it will give you both the o/p's . > > Are you using the same hard disk with same disk block size ? > > > On Sat, Aug 6, 2011 at 9:51 PM, mani <manish...@gmail.com> wrote: > >> Dear Ashish, >> >> The ls uses st_size while du uses st_blocks. >> try using the ls -ls it will give you both the o/p's . >> >> Thanks >> Manish >> >> On Fri, Aug 5, 2011 at 7:45 AM, Ashish Sangwan >> <ashishsangw...@gmail.com>wrote: >> >>> I write 1 program to create sparse file which contains alternate empty >>> blocks and data blocks. For example block1=empty, block2=data, block3=empty >>> ..... >>> >>> #define BLOCK_SIZE 4096 >>> void *buf; >>> int main(int argc, char **argv) >>> { >>> buf=malloc(512); >>> memset(buf,"a",512); >>> int fd=0; >>> int i; >>> int sector_per_block=BLOCK_SIZE/512; >>> int block_count=4; >>> if(argc !=2 ){ >>> printf("Wrong usage\n USAGE: program absolute_path_to_write\n"); >>> _exit(-1); >>> } >>> fd=open(argv[1],O_RDWR | O_CREAT,0666); >>> if(fd <= 0){ >>> printf("file open failed\n"); >>> _exit(0); >>> } >>> while(block_count > 0){ >>> lseek(fd,BLOCK_SIZE,SEEK_CUR); >>> block_count--; >>> for(i=0;i<sector_per_block;i++) >>> write(fd,buf,512); >>> block_count--; >>> } >>> close(fd); >>> return 0; >>> } >>> >>> Suppose, I create a new_sparse_file using this above code. >>> >>> When I run this program, on ext3 FS with block size 4KB, ls -lh shows >>> size of new_sparse_file as 16KB, while du -h shows 8 kb, which, I think is >>> correct. >>> >>> On xfs, block size of 4kb, ls -lh shows 16KB but du -h shows 12kb. >>> Why are there different kinds of behavior? >>> >>> If I increase the block_count to be written so that a 200MB file is >>> created, on XFS du -h shows 187MB and on EXT3 it shows 101MB. >>> >>> _______________________________________________ >>> Kernelnewbies mailing list >>> Kernelnewbies@kernelnewbies.org >>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >>> >>> >> >
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