diff options
Diffstat (limited to 'fs/xfs/xfs_vnodeops.c')
| -rw-r--r-- | fs/xfs/xfs_vnodeops.c | 162 |
1 files changed, 41 insertions, 121 deletions
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c index c5dc7ea8526..077c86b6cb2 100644 --- a/fs/xfs/xfs_vnodeops.c +++ b/fs/xfs/xfs_vnodeops.c @@ -1708,111 +1708,6 @@ 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; int xfs_middle_retries; @@ -1946,6 +1841,45 @@ again: #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, @@ -2018,9 +1952,7 @@ xfs_remove( 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 @@ -2047,9 +1979,6 @@ xfs_remove( } } - /* - * 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); @@ -2155,7 +2084,6 @@ xfs_link( { 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; @@ -2203,15 +2131,7 @@ xfs_link( 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 & |