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Subject[PATCH 04/09] f2fs: fix race conditon on truncation with inline_data
Date
Let's consider the following scenario.

blkaddr[0] inline_data i_size i_blocks writepage truncate
NEW X 4096 2 dirty page #0
NEW X 0 change i_size
NEW X 0 2 f2fs_write_inline_data
NEW X 0 2 get_dnode_of_data
NEW X 0 2 truncate_data_blocks_range
NULL O 0 1 memcpy(inline_data)
NULL O 0 1 f2fs_put_dnode
NULL O 0 1 f2fs_truncate
NULL O 0 1 get_dnode_of_data
NULL O 0 1 *invalid block addr*

This patch adds checking inline_data flag during f2fs_truncate not to refer
corrupted block indices.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
fs/f2fs/file.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 8e68bb6..543d8c6 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -473,6 +473,12 @@ int truncate_blocks(struct inode *inode, u64 from, bool lock)
return err;
}

+ /* writepage can convert inline_data under get_donde_of_data */
+ if (f2fs_has_inline_data(inode)) {
+ f2fs_put_dnode(&dn);
+ goto done;
+ }
+
count = ADDRS_PER_PAGE(dn.node_page, F2FS_I(inode));

count -= dn.ofs_in_node;
--
2.1.1


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