On Wed, Mar 25, 2020 at 12:42:05PM +1100, Dave Chinner wrote: > From: Dave Chinner <dchinner@xxxxxxxxxx> > > There's lots of indent in this code which makes it a bit hard to > follow. We are also going to completely rework the inode lookup code > as part of the inode reclaim rework, so factor out the inode lookup > code from the inode cluster freeing code. > > Based on prototype code from Christoph Hellwig. > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> > --- https://lore.kernel.org/linux-xfs/20191104232000.GR4153244@magnolia/ https://lore.kernel.org/linux-xfs/20191101120521.GE59146@bfoster/ > fs/xfs/xfs_inode.c | 152 +++++++++++++++++++++++++-------------------- > 1 file changed, 84 insertions(+), 68 deletions(-) > > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > index 14b922f2a6db7..5c930863ed5b8 100644 > --- a/fs/xfs/xfs_inode.c > +++ b/fs/xfs/xfs_inode.c > @@ -2503,6 +2503,88 @@ xfs_iunlink_remove( > return error; > } > > +/* > + * Look up the inode number specified and mark it stale if it is found. If it is > + * dirty, return the inode so it can be attached to the cluster buffer so it can > + * be processed appropriately when the cluster free transaction completes. > + */ > +static struct xfs_inode * > +xfs_ifree_get_one_inode( > + struct xfs_perag *pag, > + struct xfs_inode *free_ip, > + int inum) > +{ > + struct xfs_mount *mp = pag->pag_mount; > + struct xfs_inode *ip; > + > +retry: > + rcu_read_lock(); > + ip = radix_tree_lookup(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, inum)); > + > + /* Inode not in memory, nothing to do */ > + if (!ip) > + goto out_rcu_unlock; > + > + /* > + * because this is an RCU protected lookup, we could find a recently > + * freed or even reallocated inode during the lookup. We need to check > + * under the i_flags_lock for a valid inode here. Skip it if it is not > + * valid, the wrong inode or stale. > + */ > + spin_lock(&ip->i_flags_lock); > + if (ip->i_ino != inum || __xfs_iflags_test(ip, XFS_ISTALE)) { > + spin_unlock(&ip->i_flags_lock); > + goto out_rcu_unlock; > + } > + spin_unlock(&ip->i_flags_lock); > + > + /* > + * Don't try to lock/unlock the current inode, but we _cannot_ skip the > + * other inodes that we did not find in the list attached to the buffer > + * and are not already marked stale. If we can't lock it, back off and > + * retry. > + */ > + if (ip != free_ip) { > + if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) { > + rcu_read_unlock(); > + delay(1); > + goto retry; > + } > + > + /* > + * Check the inode number again in case we're racing with > + * freeing in xfs_reclaim_inode(). See the comments in that > + * function for more information as to why the initial check is > + * not sufficient. > + */ > + if (ip->i_ino != inum) { > + xfs_iunlock(ip, XFS_ILOCK_EXCL); > + goto out_rcu_unlock; > + } > + } > + rcu_read_unlock(); > + > + xfs_iflock(ip); > + xfs_iflags_set(ip, XFS_ISTALE); > + > + /* > + * We don't need to attach clean inodes or those only with unlogged > + * changes (which we throw away, anyway). > + */ > + if (!ip->i_itemp || xfs_inode_clean(ip)) { > + ASSERT(ip != free_ip); > + xfs_ifunlock(ip); > + xfs_iunlock(ip, XFS_ILOCK_EXCL); > + goto out_no_inode; > + } > + return ip; > + > +out_rcu_unlock: > + rcu_read_unlock(); > +out_no_inode: > + return NULL; > +} > + > /* > * A big issue when freeing the inode cluster is that we _cannot_ skip any > * inodes that are in memory - they all must be marked stale and attached to > @@ -2603,77 +2685,11 @@ xfs_ifree_cluster( > * even trying to lock them. > */ > for (i = 0; i < igeo->inodes_per_cluster; i++) { > -retry: > - rcu_read_lock(); > - ip = radix_tree_lookup(&pag->pag_ici_root, > - XFS_INO_TO_AGINO(mp, (inum + i))); > - > - /* Inode not in memory, nothing to do */ > - if (!ip) { > - rcu_read_unlock(); > + ip = xfs_ifree_get_one_inode(pag, free_ip, inum + i); > + if (!ip) > continue; > - } > - > - /* > - * because this is an RCU protected lookup, we could > - * find a recently freed or even reallocated inode > - * during the lookup. We need to check under the > - * i_flags_lock for a valid inode here. Skip it if it > - * is not valid, the wrong inode or stale. > - */ > - spin_lock(&ip->i_flags_lock); > - if (ip->i_ino != inum + i || > - __xfs_iflags_test(ip, XFS_ISTALE)) { > - spin_unlock(&ip->i_flags_lock); > - rcu_read_unlock(); > - continue; > - } > - spin_unlock(&ip->i_flags_lock); > - > - /* > - * Don't try to lock/unlock the current inode, but we > - * _cannot_ skip the other inodes that we did not find > - * in the list attached to the buffer and are not > - * already marked stale. If we can't lock it, back off > - * and retry. > - */ > - if (ip != free_ip) { > - if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) { > - rcu_read_unlock(); > - delay(1); > - goto retry; > - } > - > - /* > - * Check the inode number again in case we're > - * racing with freeing in xfs_reclaim_inode(). > - * See the comments in that function for more > - * information as to why the initial check is > - * not sufficient. > - */ > - if (ip->i_ino != inum + i) { > - xfs_iunlock(ip, XFS_ILOCK_EXCL); > - rcu_read_unlock(); > - continue; > - } > - } > - rcu_read_unlock(); > > - xfs_iflock(ip); > - xfs_iflags_set(ip, XFS_ISTALE); > - > - /* > - * we don't need to attach clean inodes or those only > - * with unlogged changes (which we throw away, anyway). > - */ > iip = ip->i_itemp; > - if (!iip || xfs_inode_clean(ip)) { > - ASSERT(ip != free_ip); > - xfs_ifunlock(ip); > - xfs_iunlock(ip, XFS_ILOCK_EXCL); > - continue; > - } > - > iip->ili_last_fields = iip->ili_fields; > iip->ili_fields = 0; > iip->ili_fsync_fields = 0; > -- > 2.26.0.rc2 >
