tree 65b4dc843f34f0837b10f4fbbc1763f5aae87b7b
parent 3b6bfcdb116f2cc2cab921fcac6d39d4022952d2
author Miklos Szeredi <[EMAIL PROTECTED]> Wed, 13 Jul 2005 03:58:10 -0700
committer Linus Torvalds <[EMAIL PROTECTED]> Wed, 13 Jul 2005 06:00:59 -0700
[PATCH] __wait_on_freeing_inode fix
This patch fixes queer behavior in __wait_on_freeing_inode().
If I_LOCK was not set it called yield(), effectively busy waiting for the
removal of the inode from the hash. This change was introduced within
"[PATCH] eliminate inode waitqueue hashtable" Changeset 1.1938.166.16 last
october by wli.
The solution is to restore the old behavior, of unconditionally waiting on
the waitqueue. It doesn't matter if I_LOCK is not set initally, the task
will go to sleep, and wake up when wake_up_inode() is called from
generic_delete_inode() after removing the inode from the hash chain.
Comment is also updated to better reflect current behavior.
This condition is very hard to trigger normally (simultaneous clear_inode()
with iget()) so probably only heavy stress testing can reveal any change of
behavior.
Signed-off-by: Miklos Szeredi <[EMAIL PROTECTED]>
Acked-by: Christoph Hellwig <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
fs/inode.c | 26 +++++++++-----------------
1 files changed, 9 insertions(+), 17 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1244,29 +1244,21 @@ int inode_wait(void *word)
}
/*
- * If we try to find an inode in the inode hash while it is being deleted, we
- * have to wait until the filesystem completes its deletion before reporting
- * that it isn't found. This is because iget will immediately call
- * ->read_inode, and we want to be sure that evidence of the deletion is found
- * by ->read_inode.
+ * If we try to find an inode in the inode hash while it is being
+ * deleted, we have to wait until the filesystem completes its
+ * deletion before reporting that it isn't found. This function waits
+ * until the deletion _might_ have completed. Callers are responsible
+ * to recheck inode state.
+ *
+ * It doesn't matter if I_LOCK is not set initially, a call to
+ * wake_up_inode() after removing from the hash list will DTRT.
+ *
* This is called with inode_lock held.
*/
static void __wait_on_freeing_inode(struct inode *inode)
{
wait_queue_head_t *wq;
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK);
-
- /*
- * I_FREEING and I_CLEAR are cleared in process context under
- * inode_lock, so we have to give the tasks who would clear them
- * a chance to run and acquire inode_lock.
- */
- if (!(inode->i_state & I_LOCK)) {
- spin_unlock(&inode_lock);
- yield();
- spin_lock(&inode_lock);
- return;
- }
wq = bit_waitqueue(&inode->i_state, __I_LOCK);
prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&inode_lock);
-
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