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author | 2005-07-12 13:58:10 -0700 | |
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committer | 2005-07-12 16:00:59 -0700 | |
commit | 168a9fd6a1bf91041adf9909f6c72cf747f0ca8c (patch) | |
tree | 65b4dc843f34f0837b10f4fbbc1763f5aae87b7b | |
parent | [PATCH] lower VM_DONTCOPY total_vm (diff) | |
download | linux-168a9fd6a1bf91041adf9909f6c72cf747f0ca8c.tar.gz linux-168a9fd6a1bf91041adf9909f6c72cf747f0ca8c.tar.bz2 linux-168a9fd6a1bf91041adf9909f6c72cf747f0ca8c.zip |
[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 <miklos@szeredi.hu>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r-- | fs/inode.c | 26 |
1 files changed, 9 insertions, 17 deletions
diff --git a/fs/inode.c b/fs/inode.c index 6d695037a0a3..0116d06731c2 100644 --- 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); |