Messages in this thread Patch in this message | | | From | Chao Yu <> | Subject | [PATCH] f2fs: avoid race between zero_range and background GC | Date | Thu, 26 Jul 2018 18:45:36 +0800 |
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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().
Use i_gc_rwsem[WRITE] to avoid such race condition.
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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