linux_dsm_epyc7002/fs/xfs/xfs_dquot_item.c
Brian Foster 8a62714313 xfs: fix unmount hang and memory leak on shutdown during quotaoff
AIL removal of the quotaoff start intent and free of both quotaoff
intents is currently limited to the ->iop_committed() handler of the
end intent. This executes when the end intent is committed to the
on-disk log and marks the completion of the operation. The problem
with this is it assumes the success of the operation. If a shutdown
or other error occurs during the quotaoff, it's possible for the
quotaoff task to exit without removing the start intent from the
AIL. This results in an unmount hang as the AIL cannot be emptied.
Further, no other codepath frees the intents and so this is also a
memory leak vector.

First, update the high level quotaoff error path to directly remove
and free the quotaoff start intent if it still exists in the AIL at
the time of the error. Next, update both of the start and end
quotaoff intents with an ->iop_release() callback to properly handle
transaction abort.

This means that If the quotaoff start transaction aborts, it frees
the start intent in the transaction commit path. If the filesystem
shuts down before the end transaction allocates, the quotaoff
sequence removes and frees the start intent. If the end transaction
aborts, it removes the start intent and frees both. This ensures
that a shutdown does not result in a hung unmount and that memory is
not leaked regardless of when a quotaoff error occurs.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-03-18 08:12:23 -07:00

385 lines
9.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2003 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_quota.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_trans_priv.h"
#include "xfs_qm.h"
#include "xfs_log.h"
static inline struct xfs_dq_logitem *DQUOT_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_dq_logitem, qli_item);
}
/*
* returns the number of iovecs needed to log the given dquot item.
*/
STATIC void
xfs_qm_dquot_logitem_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
*nvecs += 2;
*nbytes += sizeof(struct xfs_dq_logformat) +
sizeof(struct xfs_disk_dquot);
}
/*
* fills in the vector of log iovecs for the given dquot log item.
*/
STATIC void
xfs_qm_dquot_logitem_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_dq_logitem *qlip = DQUOT_ITEM(lip);
struct xfs_log_iovec *vecp = NULL;
struct xfs_dq_logformat *qlf;
qlf = xlog_prepare_iovec(lv, &vecp, XLOG_REG_TYPE_QFORMAT);
qlf->qlf_type = XFS_LI_DQUOT;
qlf->qlf_size = 2;
qlf->qlf_id = be32_to_cpu(qlip->qli_dquot->q_core.d_id);
qlf->qlf_blkno = qlip->qli_dquot->q_blkno;
qlf->qlf_len = 1;
qlf->qlf_boffset = qlip->qli_dquot->q_bufoffset;
xlog_finish_iovec(lv, vecp, sizeof(struct xfs_dq_logformat));
xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_DQUOT,
&qlip->qli_dquot->q_core,
sizeof(struct xfs_disk_dquot));
}
/*
* Increment the pin count of the given dquot.
*/
STATIC void
xfs_qm_dquot_logitem_pin(
struct xfs_log_item *lip)
{
struct xfs_dquot *dqp = DQUOT_ITEM(lip)->qli_dquot;
ASSERT(XFS_DQ_IS_LOCKED(dqp));
atomic_inc(&dqp->q_pincount);
}
/*
* Decrement the pin count of the given dquot, and wake up
* anyone in xfs_dqwait_unpin() if the count goes to 0. The
* dquot must have been previously pinned with a call to
* xfs_qm_dquot_logitem_pin().
*/
STATIC void
xfs_qm_dquot_logitem_unpin(
struct xfs_log_item *lip,
int remove)
{
struct xfs_dquot *dqp = DQUOT_ITEM(lip)->qli_dquot;
ASSERT(atomic_read(&dqp->q_pincount) > 0);
if (atomic_dec_and_test(&dqp->q_pincount))
wake_up(&dqp->q_pinwait);
}
/*
* This is called to wait for the given dquot to be unpinned.
* Most of these pin/unpin routines are plagiarized from inode code.
*/
void
xfs_qm_dqunpin_wait(
struct xfs_dquot *dqp)
{
ASSERT(XFS_DQ_IS_LOCKED(dqp));
if (atomic_read(&dqp->q_pincount) == 0)
return;
/*
* Give the log a push so we don't wait here too long.
*/
xfs_log_force(dqp->q_mount, 0);
wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
}
/*
* Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
* have been failed during writeback
*
* this informs the AIL that the dquot is already flush locked on the next push,
* and acquires a hold on the buffer to ensure that it isn't reclaimed before
* dirty data makes it to disk.
*/
STATIC void
xfs_dquot_item_error(
struct xfs_log_item *lip,
struct xfs_buf *bp)
{
ASSERT(!completion_done(&DQUOT_ITEM(lip)->qli_dquot->q_flush));
xfs_set_li_failed(lip, bp);
}
STATIC uint
xfs_qm_dquot_logitem_push(
struct xfs_log_item *lip,
struct list_head *buffer_list)
__releases(&lip->li_ailp->ail_lock)
__acquires(&lip->li_ailp->ail_lock)
{
struct xfs_dquot *dqp = DQUOT_ITEM(lip)->qli_dquot;
struct xfs_buf *bp = lip->li_buf;
uint rval = XFS_ITEM_SUCCESS;
int error;
if (atomic_read(&dqp->q_pincount) > 0)
return XFS_ITEM_PINNED;
/*
* The buffer containing this item failed to be written back
* previously. Resubmit the buffer for IO
*/
if (test_bit(XFS_LI_FAILED, &lip->li_flags)) {
if (!xfs_buf_trylock(bp))
return XFS_ITEM_LOCKED;
if (!xfs_buf_resubmit_failed_buffers(bp, buffer_list))
rval = XFS_ITEM_FLUSHING;
xfs_buf_unlock(bp);
return rval;
}
if (!xfs_dqlock_nowait(dqp))
return XFS_ITEM_LOCKED;
/*
* Re-check the pincount now that we stabilized the value by
* taking the quota lock.
*/
if (atomic_read(&dqp->q_pincount) > 0) {
rval = XFS_ITEM_PINNED;
goto out_unlock;
}
/*
* Someone else is already flushing the dquot. Nothing we can do
* here but wait for the flush to finish and remove the item from
* the AIL.
*/
if (!xfs_dqflock_nowait(dqp)) {
rval = XFS_ITEM_FLUSHING;
goto out_unlock;
}
spin_unlock(&lip->li_ailp->ail_lock);
error = xfs_qm_dqflush(dqp, &bp);
if (!error) {
if (!xfs_buf_delwri_queue(bp, buffer_list))
rval = XFS_ITEM_FLUSHING;
xfs_buf_relse(bp);
}
spin_lock(&lip->li_ailp->ail_lock);
out_unlock:
xfs_dqunlock(dqp);
return rval;
}
STATIC void
xfs_qm_dquot_logitem_release(
struct xfs_log_item *lip)
{
struct xfs_dquot *dqp = DQUOT_ITEM(lip)->qli_dquot;
ASSERT(XFS_DQ_IS_LOCKED(dqp));
/*
* dquots are never 'held' from getting unlocked at the end of
* a transaction. Their locking and unlocking is hidden inside the
* transaction layer, within trans_commit. Hence, no LI_HOLD flag
* for the logitem.
*/
xfs_dqunlock(dqp);
}
STATIC void
xfs_qm_dquot_logitem_committing(
struct xfs_log_item *lip,
xfs_lsn_t commit_lsn)
{
return xfs_qm_dquot_logitem_release(lip);
}
static const struct xfs_item_ops xfs_dquot_item_ops = {
.iop_size = xfs_qm_dquot_logitem_size,
.iop_format = xfs_qm_dquot_logitem_format,
.iop_pin = xfs_qm_dquot_logitem_pin,
.iop_unpin = xfs_qm_dquot_logitem_unpin,
.iop_release = xfs_qm_dquot_logitem_release,
.iop_committing = xfs_qm_dquot_logitem_committing,
.iop_push = xfs_qm_dquot_logitem_push,
.iop_error = xfs_dquot_item_error
};
/*
* Initialize the dquot log item for a newly allocated dquot.
* The dquot isn't locked at this point, but it isn't on any of the lists
* either, so we don't care.
*/
void
xfs_qm_dquot_logitem_init(
struct xfs_dquot *dqp)
{
struct xfs_dq_logitem *lp = &dqp->q_logitem;
xfs_log_item_init(dqp->q_mount, &lp->qli_item, XFS_LI_DQUOT,
&xfs_dquot_item_ops);
lp->qli_dquot = dqp;
}
/*------------------ QUOTAOFF LOG ITEMS -------------------*/
static inline struct xfs_qoff_logitem *QOFF_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_qoff_logitem, qql_item);
}
/*
* This returns the number of iovecs needed to log the given quotaoff item.
* We only need 1 iovec for an quotaoff item. It just logs the
* quotaoff_log_format structure.
*/
STATIC void
xfs_qm_qoff_logitem_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
*nvecs += 1;
*nbytes += sizeof(struct xfs_qoff_logitem);
}
STATIC void
xfs_qm_qoff_logitem_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_qoff_logitem *qflip = QOFF_ITEM(lip);
struct xfs_log_iovec *vecp = NULL;
struct xfs_qoff_logformat *qlf;
qlf = xlog_prepare_iovec(lv, &vecp, XLOG_REG_TYPE_QUOTAOFF);
qlf->qf_type = XFS_LI_QUOTAOFF;
qlf->qf_size = 1;
qlf->qf_flags = qflip->qql_flags;
xlog_finish_iovec(lv, vecp, sizeof(struct xfs_qoff_logitem));
}
/*
* There isn't much you can do to push a quotaoff item. It is simply
* stuck waiting for the log to be flushed to disk.
*/
STATIC uint
xfs_qm_qoff_logitem_push(
struct xfs_log_item *lip,
struct list_head *buffer_list)
{
return XFS_ITEM_LOCKED;
}
STATIC xfs_lsn_t
xfs_qm_qoffend_logitem_committed(
struct xfs_log_item *lip,
xfs_lsn_t lsn)
{
struct xfs_qoff_logitem *qfe = QOFF_ITEM(lip);
struct xfs_qoff_logitem *qfs = qfe->qql_start_lip;
xfs_qm_qoff_logitem_relse(qfs);
kmem_free(lip->li_lv_shadow);
kmem_free(qfe);
return (xfs_lsn_t)-1;
}
STATIC void
xfs_qm_qoff_logitem_release(
struct xfs_log_item *lip)
{
struct xfs_qoff_logitem *qoff = QOFF_ITEM(lip);
if (test_bit(XFS_LI_ABORTED, &lip->li_flags)) {
if (qoff->qql_start_lip)
xfs_qm_qoff_logitem_relse(qoff->qql_start_lip);
xfs_qm_qoff_logitem_relse(qoff);
}
}
static const struct xfs_item_ops xfs_qm_qoffend_logitem_ops = {
.iop_size = xfs_qm_qoff_logitem_size,
.iop_format = xfs_qm_qoff_logitem_format,
.iop_committed = xfs_qm_qoffend_logitem_committed,
.iop_push = xfs_qm_qoff_logitem_push,
.iop_release = xfs_qm_qoff_logitem_release,
};
static const struct xfs_item_ops xfs_qm_qoff_logitem_ops = {
.iop_size = xfs_qm_qoff_logitem_size,
.iop_format = xfs_qm_qoff_logitem_format,
.iop_push = xfs_qm_qoff_logitem_push,
.iop_release = xfs_qm_qoff_logitem_release,
};
/*
* Delete the quotaoff intent from the AIL and free it. On success,
* this should only be called for the start item. It can be used for
* either on shutdown or abort.
*/
void
xfs_qm_qoff_logitem_relse(
struct xfs_qoff_logitem *qoff)
{
struct xfs_log_item *lip = &qoff->qql_item;
ASSERT(test_bit(XFS_LI_IN_AIL, &lip->li_flags) ||
test_bit(XFS_LI_ABORTED, &lip->li_flags) ||
XFS_FORCED_SHUTDOWN(lip->li_mountp));
xfs_trans_ail_remove(lip, SHUTDOWN_LOG_IO_ERROR);
kmem_free(lip->li_lv_shadow);
kmem_free(qoff);
}
/*
* Allocate and initialize an quotaoff item of the correct quota type(s).
*/
struct xfs_qoff_logitem *
xfs_qm_qoff_logitem_init(
struct xfs_mount *mp,
struct xfs_qoff_logitem *start,
uint flags)
{
struct xfs_qoff_logitem *qf;
qf = kmem_zalloc(sizeof(struct xfs_qoff_logitem), 0);
xfs_log_item_init(mp, &qf->qql_item, XFS_LI_QUOTAOFF, start ?
&xfs_qm_qoffend_logitem_ops : &xfs_qm_qoff_logitem_ops);
qf->qql_item.li_mountp = mp;
qf->qql_start_lip = start;
qf->qql_flags = flags;
return qf;
}