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authorJan Kara <jack@suse.cz>2009-02-10 19:15:34 +0300
committerTheodore Tso <tytso@mit.edu>2009-02-10 19:15:34 +0300
commit7f5aa215088b817add9c71914b83650bdd49f8a9 (patch)
tree9b811d1f0b41a2738fc68654ae605bf5d8cf2a72 /include/linux/jbd2.h
parent9eddacf9e9c03578ef2c07c9534423e823d677f8 (diff)
downloadlinux-7f5aa215088b817add9c71914b83650bdd49f8a9.tar.xz
jbd2: Avoid possible NULL dereference in jbd2_journal_begin_ordered_truncate()
If we race with commit code setting i_transaction to NULL, we could possibly dereference it. Proper locking requires the journal pointer (to access journal->j_list_lock), which we don't have. So we have to change the prototype of the function so that filesystem passes us the journal pointer. Also add a more detailed comment about why the function jbd2_journal_begin_ordered_truncate() does what it does and how it should be used. Thanks to Dan Carpenter <error27@gmail.com> for pointing to the suspitious code. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Acked-by: Joel Becker <joel.becker@oracle.com> CC: linux-ext4@vger.kernel.org CC: ocfs2-devel@oss.oracle.com CC: mfasheh@suse.de CC: Dan Carpenter <error27@gmail.com>
Diffstat (limited to 'include/linux/jbd2.h')
-rw-r--r--include/linux/jbd2.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index b28b37eb11c6..4d248b3f1323 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1150,7 +1150,8 @@ extern int jbd2_journal_clear_err (journal_t *);
extern int jbd2_journal_bmap(journal_t *, unsigned long, unsigned long long *);
extern int jbd2_journal_force_commit(journal_t *);
extern int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *inode);
-extern int jbd2_journal_begin_ordered_truncate(struct jbd2_inode *inode, loff_t new_size);
+extern int jbd2_journal_begin_ordered_truncate(journal_t *journal,
+ struct jbd2_inode *inode, loff_t new_size);
extern void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode);
extern void jbd2_journal_release_jbd_inode(journal_t *journal, struct jbd2_inode *jinode);