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author | Jan Kara <jack@suse.cz> | 2014-06-15 23:46:28 -0400 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2014-06-15 23:46:28 -0400 |
commit | c5c7b8ddfbf8cb3b2291e515a34ab1b8982f5a2d (patch) | |
tree | 2969953563a5ed1d21570be8a9496c10f7bdcfde /fs/mbcache.c | |
parent | 7171511eaec5bf23fb06078f59784a3a0626b38f (diff) | |
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ext4: Fix buffer double free in ext4_alloc_branch()
Error recovery in ext4_alloc_branch() calls ext4_forget() even for
buffer corresponding to indirect block it did not allocate. This leads
to brelse() being called twice for that buffer (once from ext4_forget()
and once from cleanup in ext4_ind_map_blocks()) leading to buffer use
count misaccounting. Eventually (but often much later because there
are other users of the buffer) we will see messages like:
VFS: brelse: Trying to free free buffer
Another manifestation of this problem is an error:
JBD2 unexpected failure: jbd2_journal_revoke: !buffer_revoked(bh);
inconsistent data on disk
The fix is easy - don't forget buffer we did not allocate. Also add an
explanatory comment because the indexing at ext4_alloc_branch() is
somewhat subtle.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/mbcache.c')
0 files changed, 0 insertions, 0 deletions