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vfs: fix incorrect dentry_update_name_case() BUG_ON() test

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The case we should be verifying when updating the dentry name is that
the _parent_ inode (the directory) semaphore is held, not the semaphore
for the dentry itself.  It's the directory locking that rename and
readdir() etc all care about.

The comment just above even says so - but then the BUG_ON() still
checked the dentry inode itself.

Very few people noticed, because this helper function really isn't used
for very much, so you had to be using ncpfs to ever hit it.

I think I should just remove the BUG_ON (the function really has just
one user), but let's run with it fixed for a while before getting rid of
it entirely.

Reported-and-tested-by: Bongani Hlope <bonganih@bankservafrica.com>
Reported-and-tested-by: Bernd Feige <bernd.feige@uniklinik-freiburg.de>
Cc: Petr Vandrovec <petr@vandrovec.name>,
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2011-04-15 07:34:26 -07:00
parent e38f5b7450
commit 7ebfa57f6d
1 changed files with 1 additions and 1 deletions
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2
fs/dcache.c
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@ -2131,7 +2131,7 @@ EXPORT_SYMBOL(d_rehash);
*/
void dentry_update_name_case(struct dentry *dentry, struct qstr *name)
{
BUG_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
BUG_ON(!mutex_is_locked(&dentry->d_parent->d_inode->i_mutex));
BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */
spin_lock(&dentry->d_lock);