From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Fri, 12 Sep 2014 15:35:58 +0000 (+0900)
Subject: f2fs: fix double lock for inode page during roll-foward recovery
X-Git-Tag: fixes-for-v3.18-merge-window~8^2~25
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=60979115a69e0e7916a1c1796f902264f1350977;p=pandora-kernel.git

f2fs: fix double lock for inode page during roll-foward recovery

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@kernel.org>
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