If the inode is same and its data index are needed to truncate, we can fall into
double lock for its inode page via get_dnode_of_data.
Error case is like this.
1. write data 1, 2, 3, 4, 5 in inode #4.
2. write data 100, 102, 103, 104, 105 in dnode #6 of inode #4.
3. sync
4. update data 100->106 in dnode #6.
5. fsync inode #4.
6. power-cut
-> Then,
1. go back to #3's checkpoint
2. in do_recover_data, get_dnode_of_data() gets inode #4.
3. detect 100->106 in dnode #6.
4. check_index_in_prev_nodes tries to truncate 100 in dnode #6.
5. to trigger truncate_hole, get_dnode_of_data should grab inode #4.
6. detect *kernel hang*
This patch should resolve that bug.
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/recovery.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index dbeb32d..5638c05 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -306,16 +306,30 @@ got_it:
ino = ino_of_node(node_page);
f2fs_put_page(node_page, 1);
- /* Deallocate previous index in the node page */
- inode = f2fs_iget(sbi->sb, ino);
- if (IS_ERR(inode))
- return PTR_ERR(inode);
+ if (ino != dn->inode->i_ino) {
+ /* Deallocate previous index in the node page */
+ inode = f2fs_iget(sbi->sb, ino);
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+ } else {
+ inode = dn->inode;
+ }
bidx = start_bidx_of_node(offset, F2FS_I(inode)) +
- le16_to_cpu(sum.ofs_in_node);
+ le16_to_cpu(sum.ofs_in_node);
- truncate_hole(inode, bidx, bidx + 1);
- iput(inode);
+ if (ino != dn->inode->i_ino) {
+ truncate_hole(inode, bidx, bidx + 1);
+ iput(inode);
+ } else {
+ struct dnode_of_data tdn;
+ set_new_dnode(&tdn, inode, dn->inode_page, NULL, 0);
+ if (get_dnode_of_data(&tdn, bidx, LOOKUP_NODE))
+ return 0;
+ if (tdn.data_blkaddr != NULL_ADDR)
+ truncate_data_blocks_range(&tdn, 1);
+ f2fs_put_page(tdn.node_page, 1);
+ }
return 0;
}
--
1.8.5.2 (Apple Git-48)
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