fs: avoid I_NEW inodes

To be on the safe side, it should be less fragile to exclude I_NEW inodes
from inode list scans by default (unless there is an important reason to
have them).

Normally they will get excluded (eg.  by zero refcount or writecount etc),
however it is a bit fragile for list walkers to know exactly what parts of
the inode state is set up and valid to test when in I_NEW.  So along these
lines, move I_NEW checks upward as well (sometimes taking I_FREEING etc
checks with them too -- this shouldn't be a problem should it?)

Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 8 insertions, 2 deletions

diff --git a/fs/dquot.c b/fs/dquot.c
index bca3cac4bee7..cb1c3bc324de 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -789,12 +789,12 @@ static void add_dquot_ref(struct super_block *sb, int type)
 
         spin_lock(&inode_lock);
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
+                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+                        continue;
                 if (!atomic_read(&inode->i_writecount))
                         continue;
                 if (!dqinit_needed(inode, type))
                         continue;
-                if (inode->i_state & (I_FREEING|I_WILL_FREE))
-                        continue;
 
                 __iget(inode);
                 spin_unlock(&inode_lock);
@@ -870,6 +870,12 @@ static void remove_dquot_ref(struct super_block *sb, int type,
 
         spin_lock(&inode_lock);
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
+                /*
+                 *  We have to scan also I_NEW inodes because they can already
+                 *  have quota pointer initialized. Luckily, we need to touch
+                 *  only quota pointers and these have separate locking
+                 *  (dqptr_sem).
+                 */
                 if (!IS_NOQUOTA(inode))
                         remove_inode_dquot_ref(inode, type, tofree_head);
         }