xfs_agnumber_t
xfs_filestream_lookup_ag(
xfs_inode_t *ip)
{
xfs_mru_cache_t *cache;
fstrm_item_t *item;
xfs_agnumber_t ag;
int ref;
if (!(ip->i_d.di_mode & (S_IFREG | S_IFDIR))) {
ASSERT(0);
return NULLAGNUMBER;
}
cache = ip->i_mount->m_filestream;
item = xfs_mru_cache_lookup(cache, ip->i_ino);
if (!item) {
TRACE_LOOKUP(ip->i_mount, ip, NULL, NULLAGNUMBER, 0);
return NULLAGNUMBER;
}
ASSERT(ip == item->ip);
ag = item->ag;
ref = xfs_filestream_peek_ag(ip->i_mount, ag);
xfs_mru_cache_done(cache);
TRACE_LOOKUP(ip->i_mount, ip, item->pip, ag, ref);
return ag;
}
int
xfs_filestream_associate(
xfs_inode_t *pip,
xfs_inode_t *ip)
{
xfs_mount_t *mp;
xfs_mru_cache_t *cache;
fstrm_item_t *item;
xfs_agnumber_t ag, rotorstep, startag;
int err = 0;
ASSERT(pip->i_d.di_mode & S_IFDIR);
ASSERT(ip->i_d.di_mode & S_IFREG);
if (!(pip->i_d.di_mode & S_IFDIR) || !(ip->i_d.di_mode & S_IFREG))
return -EINVAL;
mp = pip->i_mount;
cache = mp->m_filestream;
/*
* We have a problem, Houston.
*
* Taking the iolock here violates inode locking order - we already
* hold the ilock. Hence if we block getting this lock we may never
* wake. Unfortunately, that means if we can't get the lock, we're
* screwed in terms of getting a stream association - we can't spin
* waiting for the lock because someone else is waiting on the lock we
* hold and we cannot drop that as we are in a transaction here.
*
* Lucky for us, this inversion is not a problem because it's a
* directory inode that we are trying to lock here.
*
* So, if we can't get the iolock without sleeping then just give up
*/
if (!xfs_ilock_nowait(pip, XFS_IOLOCK_EXCL))
return 1;
/* If the parent directory is already in the cache, use its AG. */
item = xfs_mru_cache_lookup(cache, pip->i_ino);
if (item) {
ASSERT(item->ip == pip);
ag = item->ag;
xfs_mru_cache_done(cache);
TRACE_LOOKUP(mp, pip, pip, ag, xfs_filestream_peek_ag(mp, ag));
err = _xfs_filestream_update_ag(ip, pip, ag);
goto exit;
}
/*
* Set the starting AG using the rotor for inode32, otherwise
* use the directory inode's AG.
*/
if (mp->m_flags & XFS_MOUNT_32BITINODES) {
rotorstep = xfs_rotorstep;
startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
mp->m_agfrotor = (mp->m_agfrotor + 1) %
(mp->m_sb.sb_agcount * rotorstep);
} else
startag = XFS_INO_TO_AGNO(mp, pip->i_ino);
/* Pick a new AG for the parent inode starting at startag. */
err = _xfs_filestream_pick_ag(mp, startag, &ag, 0, 0);
if (err || ag == NULLAGNUMBER)
goto exit_did_pick;
/* Associate the parent inode with the AG. */
err = _xfs_filestream_update_ag(pip, NULL, ag);
if (err)
goto exit_did_pick;
/* Associate the file inode with the AG. */
err = _xfs_filestream_update_ag(ip, pip, ag);
if (err)
goto exit_did_pick;
TRACE_ASSOCIATE(mp, ip, pip, ag, xfs_filestream_peek_ag(mp, ag));
exit_did_pick:
/*
* If _xfs_filestream_pick_ag() returned a valid AG, remove the
* reference it took on it, since the file and directory will have taken
* their own now if they were successfully cached.
*/
if (ag != NULLAGNUMBER)
xfs_filestream_put_ag(mp, ag);
exit:
xfs_iunlock(pip, XFS_IOLOCK_EXCL);
return -err;
}
int
xfs_filestream_associate(
xfs_inode_t *pip,
xfs_inode_t *ip)
{
xfs_mount_t *mp;
xfs_mru_cache_t *cache;
fstrm_item_t *item;
xfs_agnumber_t ag, rotorstep, startag;
int err = 0;
ASSERT(S_ISDIR(pip->i_d.di_mode));
ASSERT(S_ISREG(ip->i_d.di_mode));
if (!S_ISDIR(pip->i_d.di_mode) || !S_ISREG(ip->i_d.di_mode))
return -EINVAL;
mp = pip->i_mount;
cache = mp->m_filestream;
if (!xfs_ilock_nowait(pip, XFS_IOLOCK_EXCL))
return 1;
item = xfs_mru_cache_lookup(cache, pip->i_ino);
if (item) {
ASSERT(item->ip == pip);
ag = item->ag;
xfs_mru_cache_done(cache);
TRACE_LOOKUP(mp, pip, pip, ag, xfs_filestream_peek_ag(mp, ag));
err = _xfs_filestream_update_ag(ip, pip, ag);
goto exit;
}
if (mp->m_flags & XFS_MOUNT_32BITINODES) {
rotorstep = xfs_rotorstep;
startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
mp->m_agfrotor = (mp->m_agfrotor + 1) %
(mp->m_sb.sb_agcount * rotorstep);
} else
startag = XFS_INO_TO_AGNO(mp, pip->i_ino);
err = _xfs_filestream_pick_ag(mp, startag, &ag, 0, 0);
if (err || ag == NULLAGNUMBER)
goto exit_did_pick;
err = _xfs_filestream_update_ag(pip, NULL, ag);
if (err)
goto exit_did_pick;
err = _xfs_filestream_update_ag(ip, pip, ag);
if (err)
goto exit_did_pick;
TRACE_ASSOCIATE(mp, ip, pip, ag, xfs_filestream_peek_ag(mp, ag));
exit_did_pick:
if (ag != NULLAGNUMBER)
xfs_filestream_put_ag(mp, ag);
exit:
xfs_iunlock(pip, XFS_IOLOCK_EXCL);
return -err;
}
