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f2fs: avoid race condition in handling wait_io

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__submit_merged_bio    f2fs_write_end_io        f2fs_write_end_io
                       wait_io = X              wait_io = x
                       complete(X)              complete(X)
                       wait_io = NULL
wait_for_completion()
free(X)
                                                 spin_lock(X)
                                                 kernel panic

In order to avoid this, this patch removes the wait_io facility.
Instead, we can use wait_on_all_pages_writeback(sbi) to wait for end_ios.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jaegeuk Kim 2014-10-29 14:37:22 -07:00
parent adf4983bde
commit 6a8f8ca582
3 changed files with 10 additions and 29 deletions
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3
fs/f2fs/checkpoint.c
View File

@ -978,6 +978,9 @@ static void do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
/* Here, we only have one bio having CP pack */
sync_meta_pages(sbi, META_FLUSH, LONG_MAX);
/* wait for previous submitted meta pages writeback */
wait_on_all_pages_writeback(sbi);
release_dirty_inode(sbi);
if (unlikely(f2fs_cp_error(sbi)))

35
fs/f2fs/data.c
View File

@ -61,11 +61,6 @@ static void f2fs_write_end_io(struct bio *bio, int err)
dec_page_count(sbi, F2FS_WRITEBACK);
}
if (sbi->wait_io) {
complete(sbi->wait_io);
sbi->wait_io = NULL;
}
if (!get_pages(sbi, F2FS_WRITEBACK) &&
!list_empty(&sbi->cp_wait.task_list))
wake_up(&sbi->cp_wait);
@ -95,34 +90,18 @@ static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
static void __submit_merged_bio(struct f2fs_bio_info *io)
{
struct f2fs_io_info *fio = &io->fio;
int rw;
if (!io->bio)
return;
rw = fio->rw;
if (is_read_io(rw)) {
trace_f2fs_submit_read_bio(io->sbi->sb, rw,
fio->type, io->bio);
submit_bio(rw, io->bio);
} else {
trace_f2fs_submit_write_bio(io->sbi->sb, rw,
fio->type, io->bio);
/*
* META_FLUSH is only from the checkpoint procedure, and we
* should wait this metadata bio for FS consistency.
*/
if (fio->type == META_FLUSH) {
DECLARE_COMPLETION_ONSTACK(wait);
io->sbi->wait_io = &wait;
submit_bio(rw, io->bio);
wait_for_completion(&wait);
} else {
submit_bio(rw, io->bio);
}
}
if (is_read_io(fio->rw))
trace_f2fs_submit_read_bio(io->sbi->sb, fio->rw,
fio->type, io->bio);
else
trace_f2fs_submit_write_bio(io->sbi->sb, fio->rw,
fio->type, io->bio);
submit_bio(fio->rw, io->bio);
io->bio = NULL;
}

1
fs/f2fs/f2fs.h
View File

@ -516,7 +516,6 @@ struct f2fs_sb_info {
/* for bio operations */
struct f2fs_bio_info read_io; /* for read bios */
struct f2fs_bio_info write_io[NR_PAGE_TYPE]; /* for write bios */
struct completion *wait_io; /* for completion bios */
/* for checkpoint */
struct f2fs_checkpoint *ckpt; /* raw checkpoint pointer */