Messages in this thread | | | Date | Fri, 27 Jul 2018 19:29:16 +0900 | From | Jaegeuk Kim <> | Subject | Re: [PATCH] f2fs: avoid race between zero_range and background GC |
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On 07/26, Chao Yu wrote: > Thread A Background GC > - f2fs_zero_range > - truncate_pagecache_range > - gc_data_segment > - get_read_data_page > - move_data_page > - set_page_dirty > - set_cold_data > - f2fs_do_zero_range > - dn->data_blkaddr = NEW_ADDR; > - f2fs_set_data_blkaddr > > Actually, we don't need to set dirty & checked flag on the page, since > all valid data in the page should be zeroed by zero_range().
But, it doesn't matter too much, right?
> Use i_gc_rwsem[WRITE] to avoid such race condition.
Hope to avoid abusing i_gc_rwsem[] tho.
> > Signed-off-by: Chao Yu <yuchao0@huawei.com> > --- > fs/f2fs/file.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index 267ec3794e1e..7bd2412a8c37 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -1309,6 +1309,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, > if (ret) > return ret; > > + down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > down_write(&F2FS_I(inode)->i_mmap_sem); > ret = filemap_write_and_wait_range(mapping, offset, offset + len - 1); > if (ret) > @@ -1389,6 +1390,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, > } > out_sem: > up_write(&F2FS_I(inode)->i_mmap_sem); > + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > > return ret; > } > -- > 2.18.0.rc1
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