https://bugzilla.kernel.org/show_bug.cgi?id=50981 --- Comment #1 from Yongqiang Yang <xiaoqiangnk@xxxxxxxxx> 2012-11-26 05:55:56 --- which block size does the filesystem use, 1K or 4K? Yongqiang On Mon, Nov 26, 2012 at 12:31 AM, <bugzilla-daemon@xxxxxxxxxxxxxxxxxxx>wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=50981 > > Summary: ext4 : DATA CORRUPTION read and write on same 4096 > page range > Product: File System > Version: 2.5 > Kernel Version: 2.6.32 Red Hat Enterprise Linux Workstation release > 6.2 (Santiago) > Platform: All > OS/Version: Linux > Tree: Mainline > Status: NEW > Severity: high > Priority: P1 > Component: ext4 > AssignedTo: fs_ext4@xxxxxxxxxxxxxxxxxxxx > ReportedBy: meetmehiro@xxxxxxxxx > Regression: No > > > Kernal version and Red hat > > 2.6.32 , Red Hat Enterprise Linux Workstation release 6.2 (Santiago) > > > I have one scientific application, that is running on ext4 , after three to > fours days, I have started to seen that data is not correct.. then i tried > to > find simple reproducer for the same. > > Pl. find the reproducer for the same with this issue is hitting easily. > > Logs : > > ./sim ext4_write > creating the threads > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > reader thread has opened the file, fd : 4 > reader..checking data integrity > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > reader..checking data integrity > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > reader..checking data integrity > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > reader..checking data integrity > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > reader..checking data integrity > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > reader..checking data integrity > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > reader..checking data integrity > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > reader..checking data integrity > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > reader..checking data integrity > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > reader..checking data integrity > writing B at offset 0... > writing A at offset 0... > reader..checking data integrity > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > reader..checking data integrity > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > reader..checking data integrity > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > reader..checking data integrity > writing A at offset 0... > writing B at offset 0... > writing A at offset 0... > writing B at offset 0... > reader..checking data integrity > writing A at offset 0... > reader.. corrupted data, at offset : 511 > writing B at offset 0... > > > > C program : > #include <stdio.h> > #include <fcntl.h> > #include <pthread.h> > #include <assert.h> > #include <errno.h> > #include <sys/types.h> > #include <sys/stat.h> > #include <fcntl.h> > #include <unistd.h> > #include <sys/mman.h> > > pthread_t reader_id, writer_id; > > char write_buf [4096] = {0,}; > char read_buf[4096] = {0,}; > > char datafile[256] = {0,}; > int stop_write = 0; > > > > void * writer (void * arg) > { > > int fd = -1; > int count = 0; > /* this thread will open the file and write 4k data to it > alternatively > * of a different data set to the same offset > */ > /* opening the file */ > assert((fd = open(datafile, O_CREAT|O_RDWR, 0777)) != -1); > > while (1) { > > if (stop_write) > { > close(fd); > printf("write stopped\n"); > return NULL; > } > if (count % 2 == 0) > memset(write_buf, 'A', sizeof(write_buf)); > else > memset(write_buf, 'B', sizeof(write_buf)); > > > assert(lseek(fd, 0, SEEK_SET) == 0); > printf("writing %c at offset 0...\n", write_buf[0]); > assert(write(fd, write_buf, 4096) == 4096); > count ++; > > } > //pthread_exit((void *)0); > close(fd); > return NULL; > } > > void * reader(void * arg) > { > > int fd = -1; > int count = 0; > /* this thread will open the file and write 4k data to it > alternatively > * of a different data set to the same offset > */ > /* opening the file */ > assert((fd = open(datafile, O_CREAT|O_RDWR, 0777)) != -1); > printf("reader thread has opened the file, fd : %d\n", fd); > while (1) { > > memset(read_buf, '\0', 4096); > assert(lseek(fd, 0, SEEK_SET) == 0); > assert(read(fd, read_buf, 4096) == 4096); > count ++; > printf("reader..checking data integrity\n"); > int i=0; > for (i=0; i < 4095; i++) > { > int prev_char = read_buf[i]; > int next_char = read_buf[i+1]; > if (prev_char != next_char) > { > printf("reader.. corrupted data, at offset > : > %d\n", i); > stop_write = 1; > int output_fd = open("res.txt", > O_CREAT|O_RDWR, > 0777); > > assert(write(output_fd, read_buf, 4096) == > 4096); > close(output_fd); > close(fd); > return NULL; > } > } > > > } > //pthread_exit((void *)0); > close(fd); > return NULL; > } > int main (int argc, char *argv[]) > { > pthread_attr_t attr; > void * arg = NULL; > int *status; > int err = 0; > > if (argc != 2) { > printf("usage : ./reader_writer <file pathname>\n"); > exit(1); > } > > > memset(datafile, '\0', sizeof(datafile)); > strcpy(datafile, argv[1]); > > pthread_attr_init(&attr); > pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE); > > /* create the reader and writer thread */ > printf("creating the threads\n"); > if ((err = pthread_create(&writer_id, &attr, writer, (void *)arg)) > != > 0) { > printf ("pthread_create failed err no :%d\n", err); > } > if ((err = pthread_create(&reader_id, &attr, reader, (void *)arg)) > != > 0) { > printf ("pthread_create failed err no :%d\n", err); > } > pthread_attr_destroy(&attr); > > /* Wait on the other threads */ > assert(pthread_join(writer_id, (void *)&status) == 0); > assert(pthread_join(reader_id, (void *)&status) == 0); > > pthread_exit(NULL); > } > > How to run > gcc program.c -o ext4_program -lpthread > ./ext4_program ext4_write > > -- > Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email > ------- You are receiving this mail because: ------- > You are watching the assignee of the bug. > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
