reiserfs: workaround for dead loop in finish_unfinished

There is possible dead loop in finish_unfinished function.

In most situation, the call chain iput -> ...  -> reiserfs_delete_inode ->
remove_save_link will success.  But for some reason such as data
corruption, reiserfs_delete_inode fails on reiserfs_do_truncate ->
search_for_position_by_key.

Then remove_save_link won't be called.  We always get the same
"save_link_key" in the while loop in finish_unfinished function.  The
following patch adds a check for the possible dead loop and just remove
save link when deap loop.

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Lepton Wu <ytht.net@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: "Vladimir V. Saveliev" <vs@namesys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index edfd74f9f7e4db8d84c63135b331591f7be5d661..b82897ae090bdba89331029216c3ce33893415fd 100644 (file)
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -145,7 +145,7 @@ static int finish_unfinished(struct super_block *s)
 {
        INITIALIZE_PATH(path);
        struct cpu_key max_cpu_key, obj_key;
-       struct reiserfs_key save_link_key;
+       struct reiserfs_key save_link_key, last_inode_key;
        int retval = 0;
        struct item_head *ih;
        struct buffer_head *bh;
@@ -166,6 +166,8 @@ static int finish_unfinished(struct super_block *s)
        set_cpu_key_k_offset(&max_cpu_key, ~0U);
        max_cpu_key.key_length = 3;
 
+       memset(&last_inode_key, 0, sizeof(last_inode_key));
+
 #ifdef CONFIG_QUOTA
        /* Needed for iput() to work correctly and not trash data */
        if (s->s_flags & MS_ACTIVE) {
@@ -278,8 +280,18 @@ static int finish_unfinished(struct super_block *s)
                        REISERFS_I(inode)->i_flags |= i_link_saved_unlink_mask;
                        /* not completed unlink (rmdir) found */
                        reiserfs_info(s, "Removing %k..", INODE_PKEY(inode));
-                       /* removal gets completed in iput */
-                       retval = 0;
+                       if (memcmp(&last_inode_key, INODE_PKEY(inode),
+                                       sizeof(last_inode_key))){
+                               last_inode_key = *INODE_PKEY(inode);
+                               /* removal gets completed in iput */
+                               retval = 0;
+                       } else {
+                               reiserfs_warning(s, "Dead loop in "
+                                               "finish_unfinished detected, "
+                                               "just remove save link\n");
+                               retval = remove_save_link_only(s,
+                                                       &save_link_key, 0);
+                       }
                }
 
                iput(inode);