![Christoph Hellwig](/assets/img/avatar_default.png)
We now have an i_dio_count filed and surrounding infrastructure to wait for direct I/O completion instead of i_icount, and we have never needed to iocount waits for buffered I/O given that we only set the page uptodate after finishing all required work. Thus remove i_iocount, and replace the actually needed waits with calls to inode_dio_wait. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Alex Elder <aelder@sgi.com>
1064 lines
28 KiB
C
1064 lines
28 KiB
C
/*
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* Copyright (c) 2000-2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "xfs.h"
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#include "xfs_fs.h"
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#include "xfs_types.h"
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#include "xfs_bit.h"
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#include "xfs_log.h"
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#include "xfs_inum.h"
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#include "xfs_trans.h"
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#include "xfs_trans_priv.h"
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#include "xfs_sb.h"
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#include "xfs_ag.h"
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#include "xfs_mount.h"
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#include "xfs_bmap_btree.h"
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#include "xfs_inode.h"
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#include "xfs_dinode.h"
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#include "xfs_error.h"
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#include "xfs_filestream.h"
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#include "xfs_vnodeops.h"
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#include "xfs_inode_item.h"
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#include "xfs_quota.h"
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#include "xfs_trace.h"
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#include "xfs_fsops.h"
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#include <linux/kthread.h>
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#include <linux/freezer.h>
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struct workqueue_struct *xfs_syncd_wq; /* sync workqueue */
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/*
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* The inode lookup is done in batches to keep the amount of lock traffic and
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* radix tree lookups to a minimum. The batch size is a trade off between
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* lookup reduction and stack usage. This is in the reclaim path, so we can't
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* be too greedy.
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*/
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#define XFS_LOOKUP_BATCH 32
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STATIC int
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xfs_inode_ag_walk_grab(
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struct xfs_inode *ip)
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{
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struct inode *inode = VFS_I(ip);
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ASSERT(rcu_read_lock_held());
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/*
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* check for stale RCU freed inode
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*
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* If the inode has been reallocated, it doesn't matter if it's not in
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* the AG we are walking - we are walking for writeback, so if it
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* passes all the "valid inode" checks and is dirty, then we'll write
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* it back anyway. If it has been reallocated and still being
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* initialised, the XFS_INEW check below will catch it.
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*/
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spin_lock(&ip->i_flags_lock);
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if (!ip->i_ino)
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goto out_unlock_noent;
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/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
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if (__xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
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goto out_unlock_noent;
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spin_unlock(&ip->i_flags_lock);
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/* nothing to sync during shutdown */
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if (XFS_FORCED_SHUTDOWN(ip->i_mount))
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return EFSCORRUPTED;
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/* If we can't grab the inode, it must on it's way to reclaim. */
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if (!igrab(inode))
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return ENOENT;
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if (is_bad_inode(inode)) {
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IRELE(ip);
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return ENOENT;
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}
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/* inode is valid */
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return 0;
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out_unlock_noent:
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spin_unlock(&ip->i_flags_lock);
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return ENOENT;
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}
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STATIC int
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xfs_inode_ag_walk(
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struct xfs_mount *mp,
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struct xfs_perag *pag,
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int (*execute)(struct xfs_inode *ip,
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struct xfs_perag *pag, int flags),
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int flags)
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{
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uint32_t first_index;
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int last_error = 0;
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int skipped;
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int done;
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int nr_found;
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restart:
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done = 0;
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skipped = 0;
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first_index = 0;
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nr_found = 0;
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do {
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struct xfs_inode *batch[XFS_LOOKUP_BATCH];
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int error = 0;
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int i;
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rcu_read_lock();
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nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
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(void **)batch, first_index,
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XFS_LOOKUP_BATCH);
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if (!nr_found) {
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rcu_read_unlock();
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break;
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}
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/*
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* Grab the inodes before we drop the lock. if we found
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* nothing, nr == 0 and the loop will be skipped.
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*/
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for (i = 0; i < nr_found; i++) {
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struct xfs_inode *ip = batch[i];
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if (done || xfs_inode_ag_walk_grab(ip))
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batch[i] = NULL;
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/*
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* Update the index for the next lookup. Catch
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* overflows into the next AG range which can occur if
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* we have inodes in the last block of the AG and we
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* are currently pointing to the last inode.
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*
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* Because we may see inodes that are from the wrong AG
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* due to RCU freeing and reallocation, only update the
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* index if it lies in this AG. It was a race that lead
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* us to see this inode, so another lookup from the
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* same index will not find it again.
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*/
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if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag->pag_agno)
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continue;
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first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
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if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
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done = 1;
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}
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/* unlock now we've grabbed the inodes. */
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rcu_read_unlock();
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for (i = 0; i < nr_found; i++) {
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if (!batch[i])
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continue;
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error = execute(batch[i], pag, flags);
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IRELE(batch[i]);
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if (error == EAGAIN) {
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skipped++;
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continue;
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}
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if (error && last_error != EFSCORRUPTED)
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last_error = error;
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}
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/* bail out if the filesystem is corrupted. */
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if (error == EFSCORRUPTED)
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break;
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cond_resched();
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} while (nr_found && !done);
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if (skipped) {
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delay(1);
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goto restart;
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}
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return last_error;
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}
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int
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xfs_inode_ag_iterator(
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struct xfs_mount *mp,
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int (*execute)(struct xfs_inode *ip,
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struct xfs_perag *pag, int flags),
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int flags)
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{
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struct xfs_perag *pag;
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int error = 0;
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int last_error = 0;
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xfs_agnumber_t ag;
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ag = 0;
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while ((pag = xfs_perag_get(mp, ag))) {
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ag = pag->pag_agno + 1;
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error = xfs_inode_ag_walk(mp, pag, execute, flags);
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xfs_perag_put(pag);
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if (error) {
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last_error = error;
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if (error == EFSCORRUPTED)
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break;
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}
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}
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return XFS_ERROR(last_error);
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}
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STATIC int
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xfs_sync_inode_data(
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struct xfs_inode *ip,
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struct xfs_perag *pag,
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int flags)
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{
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struct inode *inode = VFS_I(ip);
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struct address_space *mapping = inode->i_mapping;
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int error = 0;
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if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
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return 0;
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if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) {
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if (flags & SYNC_TRYLOCK)
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return 0;
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xfs_ilock(ip, XFS_IOLOCK_SHARED);
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}
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error = xfs_flush_pages(ip, 0, -1, (flags & SYNC_WAIT) ?
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0 : XBF_ASYNC, FI_NONE);
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xfs_iunlock(ip, XFS_IOLOCK_SHARED);
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return error;
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}
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STATIC int
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xfs_sync_inode_attr(
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struct xfs_inode *ip,
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struct xfs_perag *pag,
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int flags)
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{
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int error = 0;
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xfs_ilock(ip, XFS_ILOCK_SHARED);
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if (xfs_inode_clean(ip))
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goto out_unlock;
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if (!xfs_iflock_nowait(ip)) {
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if (!(flags & SYNC_WAIT))
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goto out_unlock;
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xfs_iflock(ip);
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}
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if (xfs_inode_clean(ip)) {
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xfs_ifunlock(ip);
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goto out_unlock;
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}
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error = xfs_iflush(ip, flags);
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/*
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* We don't want to try again on non-blocking flushes that can't run
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* again immediately. If an inode really must be written, then that's
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* what the SYNC_WAIT flag is for.
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*/
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if (error == EAGAIN) {
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ASSERT(!(flags & SYNC_WAIT));
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error = 0;
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}
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out_unlock:
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xfs_iunlock(ip, XFS_ILOCK_SHARED);
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return error;
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}
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/*
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* Write out pagecache data for the whole filesystem.
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*/
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STATIC int
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xfs_sync_data(
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struct xfs_mount *mp,
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int flags)
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{
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int error;
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ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0);
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error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags);
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if (error)
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return XFS_ERROR(error);
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xfs_log_force(mp, (flags & SYNC_WAIT) ? XFS_LOG_SYNC : 0);
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return 0;
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}
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/*
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* Write out inode metadata (attributes) for the whole filesystem.
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*/
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STATIC int
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xfs_sync_attr(
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struct xfs_mount *mp,
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int flags)
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{
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ASSERT((flags & ~SYNC_WAIT) == 0);
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return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags);
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}
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STATIC int
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xfs_sync_fsdata(
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struct xfs_mount *mp)
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{
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struct xfs_buf *bp;
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int error;
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/*
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* If the buffer is pinned then push on the log so we won't get stuck
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* waiting in the write for someone, maybe ourselves, to flush the log.
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*
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* Even though we just pushed the log above, we did not have the
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* superblock buffer locked at that point so it can become pinned in
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* between there and here.
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*/
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bp = xfs_getsb(mp, 0);
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if (xfs_buf_ispinned(bp))
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xfs_log_force(mp, 0);
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error = xfs_bwrite(bp);
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xfs_buf_relse(bp);
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return error;
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}
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/*
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* When remounting a filesystem read-only or freezing the filesystem, we have
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* two phases to execute. This first phase is syncing the data before we
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* quiesce the filesystem, and the second is flushing all the inodes out after
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* we've waited for all the transactions created by the first phase to
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* complete. The second phase ensures that the inodes are written to their
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* location on disk rather than just existing in transactions in the log. This
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* means after a quiesce there is no log replay required to write the inodes to
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* disk (this is the main difference between a sync and a quiesce).
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*/
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/*
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* First stage of freeze - no writers will make progress now we are here,
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* so we flush delwri and delalloc buffers here, then wait for all I/O to
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* complete. Data is frozen at that point. Metadata is not frozen,
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* transactions can still occur here so don't bother flushing the buftarg
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* because it'll just get dirty again.
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*/
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int
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xfs_quiesce_data(
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struct xfs_mount *mp)
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{
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int error, error2 = 0;
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xfs_qm_sync(mp, SYNC_TRYLOCK);
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xfs_qm_sync(mp, SYNC_WAIT);
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/* force out the newly dirtied log buffers */
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xfs_log_force(mp, XFS_LOG_SYNC);
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/* write superblock and hoover up shutdown errors */
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error = xfs_sync_fsdata(mp);
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/* make sure all delwri buffers are written out */
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xfs_flush_buftarg(mp->m_ddev_targp, 1);
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/* mark the log as covered if needed */
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if (xfs_log_need_covered(mp))
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error2 = xfs_fs_log_dummy(mp);
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/* flush data-only devices */
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if (mp->m_rtdev_targp)
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XFS_bflush(mp->m_rtdev_targp);
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return error ? error : error2;
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}
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STATIC void
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xfs_quiesce_fs(
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struct xfs_mount *mp)
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{
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int count = 0, pincount;
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xfs_reclaim_inodes(mp, 0);
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xfs_flush_buftarg(mp->m_ddev_targp, 0);
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/*
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* This loop must run at least twice. The first instance of the loop
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* will flush most meta data but that will generate more meta data
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* (typically directory updates). Which then must be flushed and
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* logged before we can write the unmount record. We also so sync
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* reclaim of inodes to catch any that the above delwri flush skipped.
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*/
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do {
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xfs_reclaim_inodes(mp, SYNC_WAIT);
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xfs_sync_attr(mp, SYNC_WAIT);
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pincount = xfs_flush_buftarg(mp->m_ddev_targp, 1);
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if (!pincount) {
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delay(50);
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count++;
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}
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} while (count < 2);
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}
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/*
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* Second stage of a quiesce. The data is already synced, now we have to take
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* care of the metadata. New transactions are already blocked, so we need to
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* wait for any remaining transactions to drain out before proceeding.
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*/
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void
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xfs_quiesce_attr(
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struct xfs_mount *mp)
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{
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int error = 0;
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/* wait for all modifications to complete */
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while (atomic_read(&mp->m_active_trans) > 0)
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delay(100);
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/* flush inodes and push all remaining buffers out to disk */
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xfs_quiesce_fs(mp);
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/*
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* Just warn here till VFS can correctly support
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* read-only remount without racing.
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*/
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WARN_ON(atomic_read(&mp->m_active_trans) != 0);
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/* Push the superblock and write an unmount record */
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error = xfs_log_sbcount(mp);
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if (error)
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xfs_warn(mp, "xfs_attr_quiesce: failed to log sb changes. "
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"Frozen image may not be consistent.");
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xfs_log_unmount_write(mp);
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xfs_unmountfs_writesb(mp);
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}
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static void
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xfs_syncd_queue_sync(
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struct xfs_mount *mp)
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{
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queue_delayed_work(xfs_syncd_wq, &mp->m_sync_work,
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msecs_to_jiffies(xfs_syncd_centisecs * 10));
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}
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/*
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* Every sync period we need to unpin all items, reclaim inodes and sync
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* disk quotas. We might need to cover the log to indicate that the
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* filesystem is idle and not frozen.
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*/
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STATIC void
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xfs_sync_worker(
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struct work_struct *work)
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{
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struct xfs_mount *mp = container_of(to_delayed_work(work),
|
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struct xfs_mount, m_sync_work);
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int error;
|
|
|
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if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
|
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/* dgc: errors ignored here */
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if (mp->m_super->s_frozen == SB_UNFROZEN &&
|
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xfs_log_need_covered(mp))
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error = xfs_fs_log_dummy(mp);
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else
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xfs_log_force(mp, 0);
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error = xfs_qm_sync(mp, SYNC_TRYLOCK);
|
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|
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/* start pushing all the metadata that is currently dirty */
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xfs_ail_push_all(mp->m_ail);
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}
|
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|
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/* queue us up again */
|
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xfs_syncd_queue_sync(mp);
|
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}
|
|
|
|
/*
|
|
* Queue a new inode reclaim pass if there are reclaimable inodes and there
|
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* isn't a reclaim pass already in progress. By default it runs every 5s based
|
|
* on the xfs syncd work default of 30s. Perhaps this should have it's own
|
|
* tunable, but that can be done if this method proves to be ineffective or too
|
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* aggressive.
|
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*/
|
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static void
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xfs_syncd_queue_reclaim(
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struct xfs_mount *mp)
|
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{
|
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|
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/*
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* We can have inodes enter reclaim after we've shut down the syncd
|
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* workqueue during unmount, so don't allow reclaim work to be queued
|
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* during unmount.
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*/
|
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if (!(mp->m_super->s_flags & MS_ACTIVE))
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return;
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|
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rcu_read_lock();
|
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if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
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queue_delayed_work(xfs_syncd_wq, &mp->m_reclaim_work,
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msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10));
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}
|
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rcu_read_unlock();
|
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}
|
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|
|
/*
|
|
* This is a fast pass over the inode cache to try to get reclaim moving on as
|
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* many inodes as possible in a short period of time. It kicks itself every few
|
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* seconds, as well as being kicked by the inode cache shrinker when memory
|
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* goes low. It scans as quickly as possible avoiding locked inodes or those
|
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* already being flushed, and once done schedules a future pass.
|
|
*/
|
|
STATIC void
|
|
xfs_reclaim_worker(
|
|
struct work_struct *work)
|
|
{
|
|
struct xfs_mount *mp = container_of(to_delayed_work(work),
|
|
struct xfs_mount, m_reclaim_work);
|
|
|
|
xfs_reclaim_inodes(mp, SYNC_TRYLOCK);
|
|
xfs_syncd_queue_reclaim(mp);
|
|
}
|
|
|
|
/*
|
|
* Flush delayed allocate data, attempting to free up reserved space
|
|
* from existing allocations. At this point a new allocation attempt
|
|
* has failed with ENOSPC and we are in the process of scratching our
|
|
* heads, looking about for more room.
|
|
*
|
|
* Queue a new data flush if there isn't one already in progress and
|
|
* wait for completion of the flush. This means that we only ever have one
|
|
* inode flush in progress no matter how many ENOSPC events are occurring and
|
|
* so will prevent the system from bogging down due to every concurrent
|
|
* ENOSPC event scanning all the active inodes in the system for writeback.
|
|
*/
|
|
void
|
|
xfs_flush_inodes(
|
|
struct xfs_inode *ip)
|
|
{
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
|
|
queue_work(xfs_syncd_wq, &mp->m_flush_work);
|
|
flush_work_sync(&mp->m_flush_work);
|
|
}
|
|
|
|
STATIC void
|
|
xfs_flush_worker(
|
|
struct work_struct *work)
|
|
{
|
|
struct xfs_mount *mp = container_of(work,
|
|
struct xfs_mount, m_flush_work);
|
|
|
|
xfs_sync_data(mp, SYNC_TRYLOCK);
|
|
xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT);
|
|
}
|
|
|
|
int
|
|
xfs_syncd_init(
|
|
struct xfs_mount *mp)
|
|
{
|
|
INIT_WORK(&mp->m_flush_work, xfs_flush_worker);
|
|
INIT_DELAYED_WORK(&mp->m_sync_work, xfs_sync_worker);
|
|
INIT_DELAYED_WORK(&mp->m_reclaim_work, xfs_reclaim_worker);
|
|
|
|
xfs_syncd_queue_sync(mp);
|
|
xfs_syncd_queue_reclaim(mp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void
|
|
xfs_syncd_stop(
|
|
struct xfs_mount *mp)
|
|
{
|
|
cancel_delayed_work_sync(&mp->m_sync_work);
|
|
cancel_delayed_work_sync(&mp->m_reclaim_work);
|
|
cancel_work_sync(&mp->m_flush_work);
|
|
}
|
|
|
|
void
|
|
__xfs_inode_set_reclaim_tag(
|
|
struct xfs_perag *pag,
|
|
struct xfs_inode *ip)
|
|
{
|
|
radix_tree_tag_set(&pag->pag_ici_root,
|
|
XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
|
|
XFS_ICI_RECLAIM_TAG);
|
|
|
|
if (!pag->pag_ici_reclaimable) {
|
|
/* propagate the reclaim tag up into the perag radix tree */
|
|
spin_lock(&ip->i_mount->m_perag_lock);
|
|
radix_tree_tag_set(&ip->i_mount->m_perag_tree,
|
|
XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
|
|
XFS_ICI_RECLAIM_TAG);
|
|
spin_unlock(&ip->i_mount->m_perag_lock);
|
|
|
|
/* schedule periodic background inode reclaim */
|
|
xfs_syncd_queue_reclaim(ip->i_mount);
|
|
|
|
trace_xfs_perag_set_reclaim(ip->i_mount, pag->pag_agno,
|
|
-1, _RET_IP_);
|
|
}
|
|
pag->pag_ici_reclaimable++;
|
|
}
|
|
|
|
/*
|
|
* We set the inode flag atomically with the radix tree tag.
|
|
* Once we get tag lookups on the radix tree, this inode flag
|
|
* can go away.
|
|
*/
|
|
void
|
|
xfs_inode_set_reclaim_tag(
|
|
xfs_inode_t *ip)
|
|
{
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
struct xfs_perag *pag;
|
|
|
|
pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
|
|
spin_lock(&pag->pag_ici_lock);
|
|
spin_lock(&ip->i_flags_lock);
|
|
__xfs_inode_set_reclaim_tag(pag, ip);
|
|
__xfs_iflags_set(ip, XFS_IRECLAIMABLE);
|
|
spin_unlock(&ip->i_flags_lock);
|
|
spin_unlock(&pag->pag_ici_lock);
|
|
xfs_perag_put(pag);
|
|
}
|
|
|
|
STATIC void
|
|
__xfs_inode_clear_reclaim(
|
|
xfs_perag_t *pag,
|
|
xfs_inode_t *ip)
|
|
{
|
|
pag->pag_ici_reclaimable--;
|
|
if (!pag->pag_ici_reclaimable) {
|
|
/* clear the reclaim tag from the perag radix tree */
|
|
spin_lock(&ip->i_mount->m_perag_lock);
|
|
radix_tree_tag_clear(&ip->i_mount->m_perag_tree,
|
|
XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
|
|
XFS_ICI_RECLAIM_TAG);
|
|
spin_unlock(&ip->i_mount->m_perag_lock);
|
|
trace_xfs_perag_clear_reclaim(ip->i_mount, pag->pag_agno,
|
|
-1, _RET_IP_);
|
|
}
|
|
}
|
|
|
|
void
|
|
__xfs_inode_clear_reclaim_tag(
|
|
xfs_mount_t *mp,
|
|
xfs_perag_t *pag,
|
|
xfs_inode_t *ip)
|
|
{
|
|
radix_tree_tag_clear(&pag->pag_ici_root,
|
|
XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
|
|
__xfs_inode_clear_reclaim(pag, ip);
|
|
}
|
|
|
|
/*
|
|
* Grab the inode for reclaim exclusively.
|
|
* Return 0 if we grabbed it, non-zero otherwise.
|
|
*/
|
|
STATIC int
|
|
xfs_reclaim_inode_grab(
|
|
struct xfs_inode *ip,
|
|
int flags)
|
|
{
|
|
ASSERT(rcu_read_lock_held());
|
|
|
|
/* quick check for stale RCU freed inode */
|
|
if (!ip->i_ino)
|
|
return 1;
|
|
|
|
/*
|
|
* do some unlocked checks first to avoid unnecessary lock traffic.
|
|
* The first is a flush lock check, the second is a already in reclaim
|
|
* check. Only do these checks if we are not going to block on locks.
|
|
*/
|
|
if ((flags & SYNC_TRYLOCK) &&
|
|
(!ip->i_flush.done || __xfs_iflags_test(ip, XFS_IRECLAIM))) {
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* The radix tree lock here protects a thread in xfs_iget from racing
|
|
* with us starting reclaim on the inode. Once we have the
|
|
* XFS_IRECLAIM flag set it will not touch us.
|
|
*
|
|
* Due to RCU lookup, we may find inodes that have been freed and only
|
|
* have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
|
|
* aren't candidates for reclaim at all, so we must check the
|
|
* XFS_IRECLAIMABLE is set first before proceeding to reclaim.
|
|
*/
|
|
spin_lock(&ip->i_flags_lock);
|
|
if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
|
|
__xfs_iflags_test(ip, XFS_IRECLAIM)) {
|
|
/* not a reclaim candidate. */
|
|
spin_unlock(&ip->i_flags_lock);
|
|
return 1;
|
|
}
|
|
__xfs_iflags_set(ip, XFS_IRECLAIM);
|
|
spin_unlock(&ip->i_flags_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Inodes in different states need to be treated differently, and the return
|
|
* value of xfs_iflush is not sufficient to get this right. The following table
|
|
* lists the inode states and the reclaim actions necessary for non-blocking
|
|
* reclaim:
|
|
*
|
|
*
|
|
* inode state iflush ret required action
|
|
* --------------- ---------- ---------------
|
|
* bad - reclaim
|
|
* shutdown EIO unpin and reclaim
|
|
* clean, unpinned 0 reclaim
|
|
* stale, unpinned 0 reclaim
|
|
* clean, pinned(*) 0 requeue
|
|
* stale, pinned EAGAIN requeue
|
|
* dirty, delwri ok 0 requeue
|
|
* dirty, delwri blocked EAGAIN requeue
|
|
* dirty, sync flush 0 reclaim
|
|
*
|
|
* (*) dgc: I don't think the clean, pinned state is possible but it gets
|
|
* handled anyway given the order of checks implemented.
|
|
*
|
|
* As can be seen from the table, the return value of xfs_iflush() is not
|
|
* sufficient to correctly decide the reclaim action here. The checks in
|
|
* xfs_iflush() might look like duplicates, but they are not.
|
|
*
|
|
* Also, because we get the flush lock first, we know that any inode that has
|
|
* been flushed delwri has had the flush completed by the time we check that
|
|
* the inode is clean. The clean inode check needs to be done before flushing
|
|
* the inode delwri otherwise we would loop forever requeuing clean inodes as
|
|
* we cannot tell apart a successful delwri flush and a clean inode from the
|
|
* return value of xfs_iflush().
|
|
*
|
|
* Note that because the inode is flushed delayed write by background
|
|
* writeback, the flush lock may already be held here and waiting on it can
|
|
* result in very long latencies. Hence for sync reclaims, where we wait on the
|
|
* flush lock, the caller should push out delayed write inodes first before
|
|
* trying to reclaim them to minimise the amount of time spent waiting. For
|
|
* background relaim, we just requeue the inode for the next pass.
|
|
*
|
|
* Hence the order of actions after gaining the locks should be:
|
|
* bad => reclaim
|
|
* shutdown => unpin and reclaim
|
|
* pinned, delwri => requeue
|
|
* pinned, sync => unpin
|
|
* stale => reclaim
|
|
* clean => reclaim
|
|
* dirty, delwri => flush and requeue
|
|
* dirty, sync => flush, wait and reclaim
|
|
*/
|
|
STATIC int
|
|
xfs_reclaim_inode(
|
|
struct xfs_inode *ip,
|
|
struct xfs_perag *pag,
|
|
int sync_mode)
|
|
{
|
|
int error;
|
|
|
|
restart:
|
|
error = 0;
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
if (!xfs_iflock_nowait(ip)) {
|
|
if (!(sync_mode & SYNC_WAIT))
|
|
goto out;
|
|
xfs_iflock(ip);
|
|
}
|
|
|
|
if (is_bad_inode(VFS_I(ip)))
|
|
goto reclaim;
|
|
if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
|
|
xfs_iunpin_wait(ip);
|
|
goto reclaim;
|
|
}
|
|
if (xfs_ipincount(ip)) {
|
|
if (!(sync_mode & SYNC_WAIT)) {
|
|
xfs_ifunlock(ip);
|
|
goto out;
|
|
}
|
|
xfs_iunpin_wait(ip);
|
|
}
|
|
if (xfs_iflags_test(ip, XFS_ISTALE))
|
|
goto reclaim;
|
|
if (xfs_inode_clean(ip))
|
|
goto reclaim;
|
|
|
|
/*
|
|
* Now we have an inode that needs flushing.
|
|
*
|
|
* We do a nonblocking flush here even if we are doing a SYNC_WAIT
|
|
* reclaim as we can deadlock with inode cluster removal.
|
|
* xfs_ifree_cluster() can lock the inode buffer before it locks the
|
|
* ip->i_lock, and we are doing the exact opposite here. As a result,
|
|
* doing a blocking xfs_itobp() to get the cluster buffer will result
|
|
* in an ABBA deadlock with xfs_ifree_cluster().
|
|
*
|
|
* As xfs_ifree_cluser() must gather all inodes that are active in the
|
|
* cache to mark them stale, if we hit this case we don't actually want
|
|
* to do IO here - we want the inode marked stale so we can simply
|
|
* reclaim it. Hence if we get an EAGAIN error on a SYNC_WAIT flush,
|
|
* just unlock the inode, back off and try again. Hopefully the next
|
|
* pass through will see the stale flag set on the inode.
|
|
*/
|
|
error = xfs_iflush(ip, SYNC_TRYLOCK | sync_mode);
|
|
if (sync_mode & SYNC_WAIT) {
|
|
if (error == EAGAIN) {
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
/* backoff longer than in xfs_ifree_cluster */
|
|
delay(2);
|
|
goto restart;
|
|
}
|
|
xfs_iflock(ip);
|
|
goto reclaim;
|
|
}
|
|
|
|
/*
|
|
* When we have to flush an inode but don't have SYNC_WAIT set, we
|
|
* flush the inode out using a delwri buffer and wait for the next
|
|
* call into reclaim to find it in a clean state instead of waiting for
|
|
* it now. We also don't return errors here - if the error is transient
|
|
* then the next reclaim pass will flush the inode, and if the error
|
|
* is permanent then the next sync reclaim will reclaim the inode and
|
|
* pass on the error.
|
|
*/
|
|
if (error && error != EAGAIN && !XFS_FORCED_SHUTDOWN(ip->i_mount)) {
|
|
xfs_warn(ip->i_mount,
|
|
"inode 0x%llx background reclaim flush failed with %d",
|
|
(long long)ip->i_ino, error);
|
|
}
|
|
out:
|
|
xfs_iflags_clear(ip, XFS_IRECLAIM);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
/*
|
|
* We could return EAGAIN here to make reclaim rescan the inode tree in
|
|
* a short while. However, this just burns CPU time scanning the tree
|
|
* waiting for IO to complete and xfssyncd never goes back to the idle
|
|
* state. Instead, return 0 to let the next scheduled background reclaim
|
|
* attempt to reclaim the inode again.
|
|
*/
|
|
return 0;
|
|
|
|
reclaim:
|
|
xfs_ifunlock(ip);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
|
|
XFS_STATS_INC(xs_ig_reclaims);
|
|
/*
|
|
* Remove the inode from the per-AG radix tree.
|
|
*
|
|
* Because radix_tree_delete won't complain even if the item was never
|
|
* added to the tree assert that it's been there before to catch
|
|
* problems with the inode life time early on.
|
|
*/
|
|
spin_lock(&pag->pag_ici_lock);
|
|
if (!radix_tree_delete(&pag->pag_ici_root,
|
|
XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino)))
|
|
ASSERT(0);
|
|
__xfs_inode_clear_reclaim(pag, ip);
|
|
spin_unlock(&pag->pag_ici_lock);
|
|
|
|
/*
|
|
* Here we do an (almost) spurious inode lock in order to coordinate
|
|
* with inode cache radix tree lookups. This is because the lookup
|
|
* can reference the inodes in the cache without taking references.
|
|
*
|
|
* We make that OK here by ensuring that we wait until the inode is
|
|
* unlocked after the lookup before we go ahead and free it. We get
|
|
* both the ilock and the iolock because the code may need to drop the
|
|
* ilock one but will still hold the iolock.
|
|
*/
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
|
|
xfs_qm_dqdetach(ip);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
|
|
|
|
xfs_inode_free(ip);
|
|
return error;
|
|
|
|
}
|
|
|
|
/*
|
|
* Walk the AGs and reclaim the inodes in them. Even if the filesystem is
|
|
* corrupted, we still want to try to reclaim all the inodes. If we don't,
|
|
* then a shut down during filesystem unmount reclaim walk leak all the
|
|
* unreclaimed inodes.
|
|
*/
|
|
int
|
|
xfs_reclaim_inodes_ag(
|
|
struct xfs_mount *mp,
|
|
int flags,
|
|
int *nr_to_scan)
|
|
{
|
|
struct xfs_perag *pag;
|
|
int error = 0;
|
|
int last_error = 0;
|
|
xfs_agnumber_t ag;
|
|
int trylock = flags & SYNC_TRYLOCK;
|
|
int skipped;
|
|
|
|
restart:
|
|
ag = 0;
|
|
skipped = 0;
|
|
while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
|
|
unsigned long first_index = 0;
|
|
int done = 0;
|
|
int nr_found = 0;
|
|
|
|
ag = pag->pag_agno + 1;
|
|
|
|
if (trylock) {
|
|
if (!mutex_trylock(&pag->pag_ici_reclaim_lock)) {
|
|
skipped++;
|
|
xfs_perag_put(pag);
|
|
continue;
|
|
}
|
|
first_index = pag->pag_ici_reclaim_cursor;
|
|
} else
|
|
mutex_lock(&pag->pag_ici_reclaim_lock);
|
|
|
|
do {
|
|
struct xfs_inode *batch[XFS_LOOKUP_BATCH];
|
|
int i;
|
|
|
|
rcu_read_lock();
|
|
nr_found = radix_tree_gang_lookup_tag(
|
|
&pag->pag_ici_root,
|
|
(void **)batch, first_index,
|
|
XFS_LOOKUP_BATCH,
|
|
XFS_ICI_RECLAIM_TAG);
|
|
if (!nr_found) {
|
|
done = 1;
|
|
rcu_read_unlock();
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Grab the inodes before we drop the lock. if we found
|
|
* nothing, nr == 0 and the loop will be skipped.
|
|
*/
|
|
for (i = 0; i < nr_found; i++) {
|
|
struct xfs_inode *ip = batch[i];
|
|
|
|
if (done || xfs_reclaim_inode_grab(ip, flags))
|
|
batch[i] = NULL;
|
|
|
|
/*
|
|
* Update the index for the next lookup. Catch
|
|
* overflows into the next AG range which can
|
|
* occur if we have inodes in the last block of
|
|
* the AG and we are currently pointing to the
|
|
* last inode.
|
|
*
|
|
* Because we may see inodes that are from the
|
|
* wrong AG due to RCU freeing and
|
|
* reallocation, only update the index if it
|
|
* lies in this AG. It was a race that lead us
|
|
* to see this inode, so another lookup from
|
|
* the same index will not find it again.
|
|
*/
|
|
if (XFS_INO_TO_AGNO(mp, ip->i_ino) !=
|
|
pag->pag_agno)
|
|
continue;
|
|
first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
|
|
if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
|
|
done = 1;
|
|
}
|
|
|
|
/* unlock now we've grabbed the inodes. */
|
|
rcu_read_unlock();
|
|
|
|
for (i = 0; i < nr_found; i++) {
|
|
if (!batch[i])
|
|
continue;
|
|
error = xfs_reclaim_inode(batch[i], pag, flags);
|
|
if (error && last_error != EFSCORRUPTED)
|
|
last_error = error;
|
|
}
|
|
|
|
*nr_to_scan -= XFS_LOOKUP_BATCH;
|
|
|
|
cond_resched();
|
|
|
|
} while (nr_found && !done && *nr_to_scan > 0);
|
|
|
|
if (trylock && !done)
|
|
pag->pag_ici_reclaim_cursor = first_index;
|
|
else
|
|
pag->pag_ici_reclaim_cursor = 0;
|
|
mutex_unlock(&pag->pag_ici_reclaim_lock);
|
|
xfs_perag_put(pag);
|
|
}
|
|
|
|
/*
|
|
* if we skipped any AG, and we still have scan count remaining, do
|
|
* another pass this time using blocking reclaim semantics (i.e
|
|
* waiting on the reclaim locks and ignoring the reclaim cursors). This
|
|
* ensure that when we get more reclaimers than AGs we block rather
|
|
* than spin trying to execute reclaim.
|
|
*/
|
|
if (skipped && (flags & SYNC_WAIT) && *nr_to_scan > 0) {
|
|
trylock = 0;
|
|
goto restart;
|
|
}
|
|
return XFS_ERROR(last_error);
|
|
}
|
|
|
|
int
|
|
xfs_reclaim_inodes(
|
|
xfs_mount_t *mp,
|
|
int mode)
|
|
{
|
|
int nr_to_scan = INT_MAX;
|
|
|
|
return xfs_reclaim_inodes_ag(mp, mode, &nr_to_scan);
|
|
}
|
|
|
|
/*
|
|
* Scan a certain number of inodes for reclaim.
|
|
*
|
|
* When called we make sure that there is a background (fast) inode reclaim in
|
|
* progress, while we will throttle the speed of reclaim via doing synchronous
|
|
* reclaim of inodes. That means if we come across dirty inodes, we wait for
|
|
* them to be cleaned, which we hope will not be very long due to the
|
|
* background walker having already kicked the IO off on those dirty inodes.
|
|
*/
|
|
void
|
|
xfs_reclaim_inodes_nr(
|
|
struct xfs_mount *mp,
|
|
int nr_to_scan)
|
|
{
|
|
/* kick background reclaimer and push the AIL */
|
|
xfs_syncd_queue_reclaim(mp);
|
|
xfs_ail_push_all(mp->m_ail);
|
|
|
|
xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK | SYNC_WAIT, &nr_to_scan);
|
|
}
|
|
|
|
/*
|
|
* Return the number of reclaimable inodes in the filesystem for
|
|
* the shrinker to determine how much to reclaim.
|
|
*/
|
|
int
|
|
xfs_reclaim_inodes_count(
|
|
struct xfs_mount *mp)
|
|
{
|
|
struct xfs_perag *pag;
|
|
xfs_agnumber_t ag = 0;
|
|
int reclaimable = 0;
|
|
|
|
while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
|
|
ag = pag->pag_agno + 1;
|
|
reclaimable += pag->pag_ici_reclaimable;
|
|
xfs_perag_put(pag);
|
|
}
|
|
return reclaimable;
|
|
}
|
|
|