goto std_return;
}
-#ifdef DEBUG
-/*
- * Some counters to see if (and how often) we are hitting some deadlock
- * prevention code paths.
- */
-
-int xfs_rm_locks;
-int xfs_rm_lock_delays;
-int xfs_rm_attempts;
-#endif
-
-/*
- * The following routine will lock the inodes associated with the
- * directory and the named entry in the directory. The locks are
- * acquired in increasing inode number.
- *
- * If the entry is "..", then only the directory is locked. The
- * vnode ref count will still include that from the .. entry in
- * this case.
- *
- * There is a deadlock we need to worry about. If the locked directory is
- * in the AIL, it might be blocking up the log. The next inode we lock
- * could be already locked by another thread waiting for log space (e.g
- * a permanent log reservation with a long running transaction (see
- * xfs_itruncate_finish)). To solve this, we must check if the directory
- * is in the ail and use lock_nowait. If we can't lock, we need to
- * drop the inode lock on the directory and try again. xfs_iunlock will
- * potentially push the tail if we were holding up the log.
- */
-STATIC int
-xfs_lock_dir_and_entry(
- xfs_inode_t *dp,
- xfs_inode_t *ip) /* inode of entry 'name' */
-{
- int attempts;
- xfs_ino_t e_inum;
- xfs_inode_t *ips[2];
- xfs_log_item_t *lp;
-
-#ifdef DEBUG
- xfs_rm_locks++;
-#endif
- attempts = 0;
-
-again:
- xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
-
- e_inum = ip->i_ino;
-
- xfs_itrace_ref(ip);
-
- /*
- * We want to lock in increasing inum. Since we've already
- * acquired the lock on the directory, we may need to release
- * if if the inum of the entry turns out to be less.
- */
- if (e_inum > dp->i_ino) {
- /*
- * We are already in the right order, so just
- * lock on the inode of the entry.
- * We need to use nowait if dp is in the AIL.
- */
-
- lp = (xfs_log_item_t *)dp->i_itemp;
- if (lp && (lp->li_flags & XFS_LI_IN_AIL)) {
- if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) {
- attempts++;
-#ifdef DEBUG
- xfs_rm_attempts++;
-#endif
-
- /*
- * Unlock dp and try again.
- * xfs_iunlock will try to push the tail
- * if the inode is in the AIL.
- */
-
- xfs_iunlock(dp, XFS_ILOCK_EXCL);
-
- if ((attempts % 5) == 0) {
- delay(1); /* Don't just spin the CPU */
-#ifdef DEBUG
- xfs_rm_lock_delays++;
-#endif
- }
- goto again;
- }
- } else {
- xfs_ilock(ip, XFS_ILOCK_EXCL);
- }
- } else if (e_inum < dp->i_ino) {
- xfs_iunlock(dp, XFS_ILOCK_EXCL);
-
- ips[0] = ip;
- ips[1] = dp;
- xfs_lock_inodes(ips, 2, XFS_ILOCK_EXCL);
- }
- /* else e_inum == dp->i_ino */
- /* This can happen if we're asked to lock /x/..
- * the entry is "..", which is also the parent directory.
- */
-
- return 0;
-}
-
#ifdef DEBUG
int xfs_locked_n;
int xfs_small_retries;
#endif
}
+void
+xfs_lock_two_inodes(
+ xfs_inode_t *ip0,
+ xfs_inode_t *ip1,
+ uint lock_mode)
+{
+ xfs_inode_t *temp;
+ int attempts = 0;
+ xfs_log_item_t *lp;
+
+ ASSERT(ip0->i_ino != ip1->i_ino);
+
+ if (ip0->i_ino > ip1->i_ino) {
+ temp = ip0;
+ ip0 = ip1;
+ ip1 = temp;
+ }
+
+ again:
+ xfs_ilock(ip0, xfs_lock_inumorder(lock_mode, 0));
+
+ /*
+ * If the first lock we have locked is in the AIL, we must TRY to get
+ * the second lock. If we can't get it, we must release the first one
+ * and try again.
+ */
+ lp = (xfs_log_item_t *)ip0->i_itemp;
+ if (lp && (lp->li_flags & XFS_LI_IN_AIL)) {
+ if (!xfs_ilock_nowait(ip1, xfs_lock_inumorder(lock_mode, 1))) {
+ xfs_iunlock(ip0, lock_mode);
+ if ((++attempts % 5) == 0)
+ delay(1); /* Don't just spin the CPU */
+ goto again;
+ }
+ } else {
+ xfs_ilock(ip1, xfs_lock_inumorder(lock_mode, 1));
+ }
+}
+
int
xfs_remove(
xfs_inode_t *dp,
goto out_trans_cancel;
}
- error = xfs_lock_dir_and_entry(dp, ip);
- if (error)
- goto out_trans_cancel;
+ xfs_lock_two_inodes(dp, ip, XFS_ILOCK_EXCL);
/*
* At this point, we've gotten both the directory and the entry
}
}
- /*
- * Entry must exist since we did a lookup in xfs_lock_dir_and_entry.
- */
XFS_BMAP_INIT(&free_list, &first_block);
error = xfs_dir_removename(tp, dp, name, ip->i_ino,
&first_block, &free_list, resblks);
{
xfs_mount_t *mp = tdp->i_mount;
xfs_trans_t *tp;
- xfs_inode_t *ips[2];
int error;
xfs_bmap_free_t free_list;
xfs_fsblock_t first_block;
goto error_return;
}
- if (sip->i_ino < tdp->i_ino) {
- ips[0] = sip;
- ips[1] = tdp;
- } else {
- ips[0] = tdp;
- ips[1] = sip;
- }
-
- xfs_lock_inodes(ips, 2, XFS_ILOCK_EXCL);
+ xfs_lock_two_inodes(sip, tdp, XFS_ILOCK_EXCL);
/*
* Increment vnode ref counts since xfs_trans_commit &
projects / linux-2.6-omap-h63xx.git / blobdiff