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btrfs-progs: convert: Fix data race when reporting progress

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The status display was reading the state while the task was updating
it. Use a mutex to prevent the race.

This race was detected using ThreadSanitizer and
misc-tests/005-convert-progress-thread-crash.

==================
WARNING: ThreadSanitizer: data race
  Write of size 8 by main thread:
    #0 ext2_copy_inodes btrfs-progs/convert/source-ext2.c:853
    #1 copy_inodes btrfs-progs/convert/main.c:145
    #2 do_convert btrfs-progs/convert/main.c:1297
    #3 main btrfs-progs/convert/main.c:1924

  Previous read of size 8 by thread T1:
    #0 print_copied_inodes btrfs-progs/convert/main.c:124

  Location is stack of main thread.

  Thread T1 (running) created by main thread at:
    #0 pthread_create <null>
    #1 task_start btrfs-progs/task-utils.c:50
    #2 do_convert btrfs-progs/convert/main.c:1295
    #3 main btrfs-progs/convert/main.c:1924

SUMMARY: ThreadSanitizer: data race
btrfs-progs/convert/source-ext2.c:853 in ext2_copy_inodes

Signed-off-by: Adam Buchbinder <abuchbinder@google.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Adam Buchbinder 2017-07-12 13:05:38 -07:00 committed by David Sterba
parent 0544aafcbf
commit 1639cc2a51
3 changed files with 14 additions and 0 deletions
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8
convert/main.c
View File

@ -88,6 +88,7 @@
#include <fcntl.h>
#include <unistd.h>
#include <getopt.h>
#include <pthread.h>
#include <stdbool.h>
#include "ctree.h"
@ -119,10 +120,12 @@ static void *print_copied_inodes(void *p)
task_period_start(priv->info, 1000 /* 1s */);
while (1) {
count++;
pthread_mutex_lock(&priv->mutex);
printf("copy inodes [%c] [%10llu/%10llu]\r",
work_indicator[count % 4],
(unsigned long long)priv->cur_copy_inodes,
(unsigned long long)priv->max_copy_inodes);
pthread_mutex_unlock(&priv->mutex);
fflush(stdout);
task_period_wait(priv->info);
}
@ -1287,6 +1290,11 @@ static int do_convert(const char *devname, u32 convert_flags, u32 nodesize,
}
printf("creating btrfs metadata");
ret = pthread_mutex_init(&ctx.mutex, NULL);
if (ret) {
error("failed to initialize mutex: %d", ret);
goto fail;
}
ctx.max_copy_inodes = (cctx.inodes_count - cctx.free_inodes_count);
ctx.cur_copy_inodes = 0;

3
convert/source-ext2.c
View File

@ -18,6 +18,7 @@
#include "kerncompat.h"
#include <linux/limits.h>
#include <pthread.h>
#include "disk-io.h"
#include "transaction.h"
#include "utils.h"
@ -850,7 +851,9 @@ static int ext2_copy_inodes(struct btrfs_convert_context *cctx,
ret = ext2_copy_single_inode(trans, root,
objectid, ext2_fs, ext2_ino,
&ext2_inode, convert_flags);
pthread_mutex_lock(&p->mutex);
p->cur_copy_inodes++;
pthread_mutex_unlock(&p->mutex);
if (ret)
return ret;
if (trans->blocks_used >= 4096) {

3
convert/source-fs.h
View File

@ -18,6 +18,8 @@
#define __BTRFS_CONVERT_SOURCE_FS_H__
#include "kerncompat.h"
#include <pthread.h>
#define CONV_IMAGE_SUBVOL_OBJECTID BTRFS_FIRST_FREE_OBJECTID
@ -37,6 +39,7 @@ extern const struct simple_range btrfs_reserved_ranges[3];
struct task_info;
struct task_ctx {
pthread_mutex_t mutex;
u64 max_copy_inodes;
u64 cur_copy_inodes;
struct task_info *info;