// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2016 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#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_defer.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_buf_item.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_rmap.h"
#include "xfs_refcount.h"
#include "xfs_bmap.h"
#include "xfs_alloc.h"
#include "xfs_buf.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_exchmaps.h"
static struct kmem_cache *xfs_defer_pending_cache;
/*
* Deferred Operations in XFS
*
* Due to the way locking rules work in XFS, certain transactions (block
* mapping and unmapping, typically) have permanent reservations so that
* we can roll the transaction to adhere to AG locking order rules and
* to unlock buffers between metadata updates. Prior to rmap/reflink,
* the mapping code had a mechanism to perform these deferrals for
* extents that were going to be freed; this code makes that facility
* more generic.
*
* When adding the reverse mapping and reflink features, it became
* necessary to perform complex remapping multi-transactions to comply
* with AG locking order rules, and to be able to spread a single
* refcount update operation (an operation on an n-block extent can
* update as many as n records!) among multiple transactions. XFS can
* roll a transaction to facilitate this, but using this facility
* requires us to log "intent" items in case log recovery needs to
* redo the operation, and to log "done" items to indicate that redo
* is not necessary.
*
* Deferred work is tracked in xfs_defer_pending items. Each pending
* item tracks one type of deferred work. Incoming work items (which
* have not yet had an intent logged) are attached to a pending item
* on the dop_intake list, where they wait for the caller to finish
* the deferred operations.
*
* Finishing a set of deferred operations is an involved process. To
* start, we define "rolling a deferred-op transaction" as follows:
*
* > For each xfs_defer_pending item on the dop_intake list,
* - Sort the work items in AG order. XFS locking
* order rules require us to lock buffers in AG order.
* - Create a log intent item for that type.
* - Attach it to the pending item.
* - Move the pending item from the dop_intake list to the
* dop_pending list.
* > Roll the transaction.
*
* NOTE: To avoid exceeding the transaction reservation, we limit the
* number of items that we attach to a given xfs_defer_pending.
*
* The actual finishing process looks like this:
*
* > For each xfs_defer_pending in the dop_pending list,
* - Roll the deferred-op transaction as above.
* - Create a log done item for that type, and attach it to the
* log intent item.
* - For each work item attached to the log intent item,
* * Perform the described action.
* * Attach the work item to the log done item.
* * If the result of doing the work was -EAGAIN, ->finish work
* wants a new transaction. See the "Requesting a Fresh
* Transaction while Finishing Deferred Work" section below for
* details.
*
* The key here is that we must log an intent item for all pending
* work items every time we roll the transaction, and that we must log
* a done item as soon as the work is completed. With this mechanism
* we can perform complex remapping operations, chaining intent items
* as needed.
*
* Requesting a Fresh Transaction while Finishing Deferred Work
*
* If ->finish_item decides that it needs a fresh transaction to
* finish the work, it must ask its caller (xfs_defer_finish) for a
* continuation. The most likely cause of this circumstance are the
* refcount adjust functions deciding that they've logged enough items
* to be at risk of exceeding the transaction reservation.
*
* To get a fresh transaction, we want to log the existing log done
* item to prevent the log intent item from replaying, immediately log
* a new log intent item with the unfinished work items, roll the
* transaction, and re-call ->finish_item wherever it left off. The
* log done item and the new log intent item must be in the same
* transaction or atomicity cannot be guaranteed; defer_finish ensures
* that this happens.
*
* This requires some coordination between ->finish_item and
* defer_finish. Upon deciding to request a new transaction,
* ->finish_item should update the current work item to reflect the
* unfinished work. Next, it should reset the log done item's list
* count to the number of items finished, and return -EAGAIN.
* defer_finish sees the -EAGAIN, logs the new log intent item
* with the remaining work items, and leaves the xfs_defer_pending
* item at the head of the dop_work queue. Then it rolls the
* transaction and picks up processing where it left off. It is
* required that ->finish_item must be careful to leave enough
* transaction reservation to fit the new log intent item.
*
* This is an example of remapping the extent (E, E+B) into file X at
* offset A and dealing with the extent (C, C+B) already being mapped
* there:
* +-------------------------------------------------+
* | Unmap file X startblock C offset A length B | t0
* | Intent to reduce refcount for extent (C, B) |
* | Intent to remove rmap (X, C, A, B) |
* | Intent to free extent (D, 1) (bmbt block) |
* | Intent to map (X, A, B) at startblock E |
* +-------------------------------------------------+
* | Map file X startblock E offset A length B | t1
* | Done mapping (X, E, A, B) |
* | Intent to increase refcount for extent (E, B) |
* | Intent to add rmap (X, E, A, B) |
* +-------------------------------------------------+
* | Reduce refcount for extent (C, B) | t2
* | Done reducing refcount for extent (C, 9) |
* | Intent to reduce refcount for extent (C+9, B-9) |
* | (ran out of space after 9 refcount updates) |
* +-------------------------------------------------+
* | Reduce refcount for extent (C+9, B+9) | t3
* | Done reducing refcount for extent (C+9, B-9) |
* | Increase refcount for extent (E, B) |
* | Done increasing refcount for extent (E, B) |
* | Intent to free extent (C, B) |
* | Intent to free extent (F, 1) (refcountbt block) |
* | Intent to remove rmap (F, 1, REFC) |
* +-------------------------------------------------+
* | Remove rmap (X, C, A, B) | t4
* | Done removing rmap (X, C, A, B) |
* | Add rmap (X, E, A, B) |
* | Done adding rmap (X, E, A, B) |
* | Remove rmap (F, 1, REFC) |
* | Done removing rmap (F, 1, REFC) |
* +-------------------------------------------------+
* | Free extent (C, B) | t5
* | Done freeing extent (C, B) |
* | Free extent (D, 1) |
* | Done freeing extent (D, 1) |
* | Free extent (F, 1) |
* | Done freeing extent (F, 1) |
* +-------------------------------------------------+
*
* If we should crash before t2 commits, log recovery replays
* the following intent items:
*
* - Intent to reduce refcount for extent (C, B)
* - Intent to remove rmap (X, C, A, B)
* - Intent to free extent (D, 1) (bmbt block)
* - Intent to increase refcount for extent (E, B)
* - Intent to add rmap (X, E, A, B)
*
* In the process of recovering, it should also generate and take care
* of these intent items:
*
* - Intent to free extent (C, B)
* - Intent to free extent (F, 1) (refcountbt block)
* - Intent to remove rmap (F, 1, REFC)
*
* Note that the continuation requested between t2 and t3 is likely to
* reoccur.
*/
STATIC struct xfs_log_item *
xfs_defer_barrier_create_intent(
struct xfs_trans *tp,
struct list_head *items,
unsigned int count,
bool sort)
{
return NULL;
}
STATIC void
xfs_defer_barrier_abort_intent(
struct xfs_log_item *intent)
{
/* empty */
}
STATIC struct xfs_log_item *
xfs_defer_barrier_create_done(
struct xfs_trans *tp,
struct xfs_log_item *intent,
unsigned int count)
{
return NULL;
}
STATIC int
xfs_defer_barrier_finish_item(
struct xfs_trans *tp,
struct xfs_log_item *done,
struct list_head *item,
struct xfs_btree_cur **state)
{
ASSERT(0);
return -EFSCORRUPTED;
}
STATIC void
xfs_defer_barrier_cancel_item(
struct list_head *item)
{
ASSERT(0);
}
static const struct xfs_defer_op_type xfs_barrier_defer_type = {
.max_items = 1,
.create_intent = xfs_defer_barrier_create_intent,
.abort_intent = xfs_defer_barrier_abort_intent,
.create_done = xfs_defer_barrier_create_done,
.finish_item = xfs_defer_barrier_finish_item,
.cancel_item = xfs_defer_barrier_cancel_item,
};
/* Create a log intent done item for a log intent item. */
static inline void
xfs_defer_create_done(
struct xfs_trans *tp,
struct xfs_defer_pending *dfp)
{
struct xfs_log_item *lip;
/* If there is no log intent item, there can be no log done item. */
if (!dfp->dfp_intent)
return;
/*
* Mark the transaction dirty, even on error. This ensures the
* transaction is aborted, which:
*
* 1.) releases the log intent item and frees the log done item
* 2.) shuts down the filesystem
*/
tp->t_flags |= XFS_TRANS_DIRTY;
lip = dfp->dfp_ops->create_done(tp, dfp->dfp_intent, dfp->dfp_count);
if (!lip)
return;
tp->t_flags |= XFS_TRANS_HAS_INTENT_DONE;
xfs_trans_add_item(tp, lip);
set_bit(XFS_LI_DIRTY, &lip->li_flags);
dfp->dfp_done = lip;
}
/*
* Ensure there's a log intent item associated with this deferred work item if
* the operation must be restarted on crash. Returns 1 if there's a log item;
* 0 if there isn't; or a negative errno.
*/
static int
xfs_defer_create_intent(
struct xfs_trans *tp,
struct xfs_defer_pending *dfp,
bool sort)
{
struct xfs_log_item *lip;
if (dfp->dfp_intent)
return 1;
lip = dfp->dfp_ops->create_intent(tp, &dfp->dfp_work, dfp->dfp_count,
sort);
if (!lip)
return 0;
if (IS_ERR(lip))
return PTR_ERR(lip);
tp->t_flags |= XFS_TRANS_DIRTY;
xfs_trans_add_item(tp, lip);
set_bit(XFS_LI_DIRTY, &lip->li_flags);
dfp->dfp_intent = lip;
return 1;
}
/*
* For each pending item in the intake list, log its intent item and the
* associated extents, then add the entire intake list to the end of
* the pending list.
*
* Returns 1 if at least one log item was associated with the deferred work;
* 0 if there are no log items; or a negative errno.
*/
static int
xfs_defer_create_intents(
struct xfs_trans *tp)
{
struct xfs_defer_pending *dfp;
int ret = 0;
list_for_each_entry(dfp, &tp->t_dfops, dfp_list) {
int ret2;
trace_xfs_defer_create_intent(tp->t_mountp, dfp);
ret2 = xfs_defer_create_intent(tp, dfp, true);
if (ret2 < 0)
return ret2;
ret |= ret2;
}
return ret;
}
static inline void
xfs_defer_pending_abort(
struct xfs_mount *mp,
struct xfs_defer_pending *dfp)
{
trace_xfs_defer_pending_abort(mp, dfp);
if (dfp->dfp_intent && !dfp->dfp_done) {
dfp->dfp_ops->abort_intent(dfp->dfp_intent);
dfp->dfp_intent = NULL;
}
}
static inline void
xfs_defer_pending_cancel_work(
struct xfs_mount *mp,
struct xfs_defer_pending *dfp)
{
struct list_head *pwi;
struct list_head *n;
trace_xfs_defer_cancel_list(mp, dfp);
list_del(&dfp->dfp_list);
list_for_each_safe(pwi, n, &dfp->dfp_work) {
list_del(pwi);
dfp->dfp_count--;
trace_xfs_defer_cancel_item(mp, dfp, pwi);
dfp->dfp_ops->cancel_item(pwi);
}
ASSERT(dfp->dfp_count == 0);
kmem_cache_free(xfs_defer_pending_cache, dfp);
}
STATIC void
xfs_defer_pending_abort_list(
struct xfs_mount *mp,
struct list_head *dop_list)
{
struct xfs_defer_pending *dfp;
/* Abort intent items that don't have a done item. */
list_for_each_entry(dfp, dop_list, dfp_list)
xfs_defer_pending_abort(mp, dfp);
}
/* Abort all the intents that were committed. */
STATIC void
xfs_defer_trans_abort(
struct xfs_trans *tp,
struct list_head *dop_pending)
{
trace_xfs_defer_trans_abort(tp, _RET_IP_);
xfs_defer_pending_abort_list(tp->t_mountp, dop_pending);
}
/*
* Capture resources that the caller said not to release ("held") when the
* transaction commits. Caller is responsible for zero-initializing @dres.
*/
static int
xfs_defer_save_resources(
struct xfs_defer_resources *dres,
struct xfs_trans *tp)
{
struct xfs_buf_log_item *bli;
struct xfs_inode_log_item *ili;
struct xfs_log_item *lip;
BUILD_BUG_ON(NBBY * sizeof(dres->dr_ordered) < XFS_DEFER_OPS_NR_BUFS);
list_for_each_entry(lip, &tp->t_items, li_trans) {
switch (lip->li_type) {
case XFS_LI_BUF:
bli = container_of(lip, struct xfs_buf_log_item,
bli_item);
if (bli->bli_flags & XFS_BLI_HOLD) {
if (dres->dr_bufs >= XFS_DEFER_OPS_NR_BUFS) {
ASSERT(0);
return -EFSCORRUPTED;
}
if (bli->bli_flags & XFS_BLI_ORDERED)
dres->dr_ordered |=
(1U << dres->dr_bufs);
else
xfs_trans_dirty_buf(tp, bli->bli_buf);
dres->dr_bp[dres->dr_bufs++] = bli->bli_buf;
}
break;
case XFS_LI_INODE:
ili = container_of(lip, struct xfs_inode_log_item,
ili_item);
if (ili->ili_lock_flags == 0) {
if (dres->dr_inos >= XFS_DEFER_OPS_NR_INODES) {
ASSERT(0);
return -EFSCORRUPTED;
}
xfs_trans_log_inode(tp, ili->ili_inode,
XFS_ILOG_CORE);
dres->dr_ip[dres->dr_inos++] = ili->ili_inode;
}
break;
default:
break;
}
}
return 0;
}
/* Attach the held resources to the transaction. */
static void
xfs_defer_restore_resources(
struct xfs_trans *tp,
struct xfs_defer_resources *dres)
{
unsigned short i;
/* Rejoin the joined inodes. */
for (i = 0; i < dres->dr_inos; i++)
xfs_trans_ijoin(tp, dres->dr_ip[i], 0);
/* Rejoin the buffers and dirty them so the log moves forward. */
for (i = 0; i < dres->dr_bufs; i++) {
xfs_trans_bjoin(tp, dres->dr_bp[i]);
if (dres->dr_ordered & (1U << i))
xfs_trans_ordered_buf(tp, dres->dr_bp[i]);
xfs_trans_bhold(tp, dres->dr_bp[i]);
}
}
/* Roll a transaction so we can do some deferred op processing. */
STATIC int
xfs_defer_trans_roll(
struct xfs_trans **tpp)
{
struct xfs_defer_resources dres = { };
int error;
error = xfs_defer_save_resources(&dres, *tpp);
if (error)
return error;
trace_xfs_defer_trans_roll(*tpp, _RET_IP_);
/*
* Roll the transaction. Rolling always given a new transaction (even
* if committing the old one fails!) to hand back to the caller, so we
* join the held resources to the new transaction so that we always
* return with the held resources joined to @tpp, no matter what
* happened.
*/
error = xfs_trans_roll(tpp);
xfs_defer_restore_resources(*tpp, &dres);
if (error)
trace_xfs_defer_trans_roll_error(*tpp, error);
return error;
}
/*
* Free up any items left in the list.
*/
static void
xfs_defer_cancel_list(
struct xfs_mount *mp,
struct list_head *dop_list)
{
struct xfs_defer_pending *dfp;
struct xfs_defer_pending *pli;
/*
* Free the pending items. Caller should already have arranged
* for the intent items to be released.
*/
list_for_each_entry_safe(dfp, pli, dop_list, dfp_list)
xfs_defer_pending_cancel_work(mp, dfp);
}
static inline void
xfs_defer_relog_intent(
struct xfs_trans *tp,
struct xfs_defer_pending *dfp)
{
struct xfs_log_item *lip;
xfs_defer_create_done(tp, dfp);
lip = dfp->dfp_ops->relog_intent(tp, dfp->dfp_intent, dfp->dfp_done);
if (lip) {
xfs_trans_add_item(tp, lip);
set_bit(XFS_LI_DIRTY, &lip->li_flags);
}
dfp->dfp_done = NULL;
dfp->dfp_intent = lip;
}
/*
* Prevent a log intent item from pinning the tail of the log by logging a
* done item to release the intent item; and then log a new intent item.
* The caller should provide a fresh transaction and roll it after we're done.
*/
static void
xfs_defer_relog(
struct xfs_trans **tpp,
struct list_head *dfops)
{
struct xlog *log = (*tpp)->t_mountp->m_log;
struct xfs_defer_pending *dfp;
xfs_lsn_t threshold_lsn = NULLCOMMITLSN;
ASSERT((*tpp)->t_flags & XFS_TRANS_PERM_LOG_RES);
list_for_each_entry(dfp, dfops, dfp_list) {
/*
* If the log intent item for this deferred op is not a part of
* the current log checkpoint, relog the intent item to keep
* the log tail moving forward. We're ok with this being racy
* because an incorrect decision means we'll be a little slower
* at pushing the tail.
*/
if (dfp->dfp_intent == NULL ||
xfs_log_item_in_current_chkpt(dfp->dfp_intent))
continue;
/*
* Figure out where we need the tail to be in order to maintain
* the minimum required free space in the log. Only sample
* the log threshold once per call.
*/
if (threshold_lsn == NULLCOMMITLSN) {
threshold_lsn = xfs_ail_get_push_target(log->l_ailp);
if (threshold_lsn == NULLCOMMITLSN)
break;
}
if (XFS_LSN_CMP(dfp->dfp_intent->li_lsn, threshold_lsn) >= 0)
continue;
trace_xfs_defer_relog_intent((*tpp)->t_mountp, dfp);
XFS_STATS_INC((*tpp)->t_mountp, defer_relog);
xfs_defer_relog_intent(*tpp, dfp);
}
}
/*
* Log an intent-done item for the first pending intent, and finish the work
* items.
*/
int
xfs_defer_finish_one(
struct xfs_trans *tp,
struct xfs_defer_pending *dfp)
{
const struct xfs_defer_op_type *ops = dfp->dfp_ops;
struct xfs_btree_cur *state = NULL;
struct list_head *li, *n;
int error;
trace_xfs_defer_pending_finish(tp->t_mountp, dfp);
xfs_defer_create_done(tp, dfp);
list_for_each_safe(li, n, &dfp->dfp_work) {
list_del(li);
dfp->dfp_count--;
trace_xfs_defer_finish_item(tp->t_mountp, dfp, li);
error = ops->finish_item(tp, dfp->dfp_done, li, &state);
if (error == -EAGAIN) {
int ret;
/*
* Caller wants a fresh transaction; put the work item
* back on the list and log a new log intent item to
* replace the old one. See "Requesting a Fresh
* Transaction while Finishing Deferred Work" above.
*/
list_add(li, &dfp->dfp_work);
dfp->dfp_count++;
dfp->dfp_done = NULL;
dfp->dfp_intent = NULL;
ret = xfs_defer_create_intent(tp, dfp, false);
if (ret < 0)
error = ret;
}
if (error)
goto out;
}
/* Done with the dfp, free it. */
list_del(&dfp->dfp_list);
kmem_cache_free(xfs_defer_pending_cache, dfp);
out:
if (ops->finish_cleanup)
ops->finish_cleanup(tp, state, error);
return error;
}
/* Move all paused deferred work from @tp to @paused_list. */
static void
xfs_defer_isolate_paused(
struct xfs_trans *tp,
struct list_head *paused_list)
{
struct xfs_defer_pending *dfp;
struct xfs_defer_pending *pli;
list_for_each_entry_safe(dfp, pli, &tp->t_dfops, dfp_list) {
if (!(dfp->dfp_flags & XFS_DEFER_PAUSED))
continue;
list_move_tail(&dfp->dfp_list, paused_list);
trace_xfs_defer_isolate_paused(tp->t_mountp, dfp);
}
}
/*
* Finish all the pending work. This involves logging intent items for
* any work items that wandered in since the last transaction roll (if
* one has even happened), rolling the transaction, and finishing the
* work items in the first item on the logged-and-pending list.
*
* If an inode is provided, relog it to the new transaction.
*/
int
xfs_defer_finish_noroll(
struct xfs_trans **tp)
{
struct xfs_defer_pending *dfp = NULL;
int error = 0;
LIST_HEAD(dop_pending);
LIST_HEAD(dop_paused);
ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES);
trace_xfs_defer_finish(*tp, _RET_IP_);
/* Until we run out of pending work to finish... */
while (!list_empty(&dop_pending) || !list_empty(&(*tp)->t_dfops)) {
/*
* Deferred items that are created in the process of finishing
* other deferred work items should be queued at the head of
* the pending list, which puts them ahead of the deferred work
* that was created by the caller. This keeps the number of
* pending work items to a minimum, which decreases the amount
* of time that any one intent item can stick around in memory,
* pinning the log tail.
*/
int has_intents = xfs_defer_create_intents(*tp);
xfs_defer_isolate_paused(*tp, &dop_paused);
list_splice_init(&(*tp)->t_dfops, &dop_pending);
if (has_intents < 0) {
error = has_intents;
goto out_shutdown;
}
if (has_intents || dfp) {
error = xfs_defer_trans_roll(tp);
if (error)
goto out_shutdown;
/* Relog intent items to keep the log moving. */
xfs_defer_relog(tp, &dop_pending);
xfs_defer_relog(tp, &dop_paused);
if ((*tp)->t_flags & XFS_TRANS_DIRTY) {
error = xfs_defer_trans_roll(tp);
if (error)
goto out_shutdown;
}
}
dfp = list_first_entry_or_null(&dop_pending,
struct xfs_defer_pending, dfp_list);
if (!dfp)
break;
error = xfs_defer_finish_one(*tp, dfp);
if (error && error != -EAGAIN)
goto out_shutdown;
}
/* Requeue the paused items in the outgoing transaction. */
list_splice_tail_init(&dop_paused, &(*tp)->t_dfops);
trace_xfs_defer_finish_done(*tp, _RET_IP_);
return 0;
out_shutdown:
list_splice_tail_init(&dop_paused, &dop_pending);
xfs_defer_trans_abort(*tp, &dop_pending);
xfs_force_shutdown((*tp)->t_mountp, SHUTDOWN_CORRUPT_INCORE);
trace_xfs_defer_finish_error(*tp, error);
xfs_defer_cancel_list((*tp)->t_mountp, &dop_pending);
xfs_defer_cancel(*tp);
return error;
}
int
xfs_defer_finish(
struct xfs_trans **tp)
{
#ifdef DEBUG
struct xfs_defer_pending *dfp;
#endif
int error;
/*
* Finish and roll the transaction once more to avoid returning to the
* caller with a dirty transaction.
*/
error = xfs_defer_finish_noroll(tp);
if (error)
return error;
if ((*tp)->t_flags & XFS_TRANS_DIRTY) {
error = xfs_defer_trans_roll(tp);
if (error) {
xfs_force_shutdown((*tp)->t_mountp,
SHUTDOWN_CORRUPT_INCORE);
return error;
}
}
/* Reset LOWMODE now that we've finished all the dfops. */
#ifdef DEBUG
list_for_each_entry(dfp, &(*tp)->t_dfops, dfp_list)
ASSERT(dfp->dfp_flags & XFS_DEFER_PAUSED);
#endif
(*tp)->t_flags &= ~XFS_TRANS_LOWMODE;
return 0;
}
void
xfs_defer_cancel(
struct xfs_trans *tp)
{
struct xfs_mount *mp = tp->t_mountp;
trace_xfs_defer_cancel(tp, _RET_IP_);
xfs_defer_trans_abort(tp, &tp->t_dfops);
xfs_defer_cancel_list(mp, &tp->t_dfops);
}
/*
* Return the last pending work item attached to this transaction if it matches
* the deferred op type.
*/
static inline struct xfs_defer_pending *
xfs_defer_find_last(
struct xfs_trans *tp,
const struct xfs_defer_op_type *ops)
{
struct xfs_defer_pending *dfp = NULL;
/* No dfops at all? */
if (list_empty(&tp->t_dfops))
return NULL;
dfp = list_last_entry(&tp->t_dfops, struct xfs_defer_pending,
dfp_list);
/* Wrong type? */
if (dfp->dfp_ops != ops)
return NULL;
return dfp;
}
/*
* Decide if we can add a deferred work item to the last dfops item attached
* to the transaction.
*/
static inline bool
xfs_defer_can_append(
struct xfs_defer_pending *dfp,
const struct xfs_defer_op_type *ops)
{
/* Already logged? */
if (dfp->dfp_intent)
return false;
/* Paused items cannot absorb more work */
if (dfp->dfp_flags & XFS_DEFER_PAUSED)
return NULL;
/* Already full? */
if (ops->max_items && dfp->dfp_count >= ops->max_items)
return false;
return true;
}
/* Create a new pending item at the end of the transaction list. */
static inline struct xfs_defer_pending *
xfs_defer_alloc(
struct list_head *dfops,
const struct xfs_defer_op_type *ops)
{
struct xfs_defer_pending *dfp;
dfp = kmem_cache_zalloc(xfs_defer_pending_cache,
GFP_KERNEL | __GFP_NOFAIL);
dfp->dfp_ops = ops;
INIT_LIST_HEAD(&dfp->dfp_work);
list_add_tail(&dfp->dfp_list, dfops);
return dfp;
}
/* Add an item for later deferred processing. */
struct xfs_defer_pending *
xfs_defer_add(
struct xfs_trans *tp,
struct list_head *li,
const struct xfs_defer_op_type *ops)
{
struct xfs_defer_pending *dfp = NULL;
ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
dfp = xfs_defer_find_last(tp, ops);
if (!dfp || !xfs_defer_can_append(dfp, ops))
dfp = xfs_defer_alloc(&tp->t_dfops, ops);
xfs_defer_add_item(dfp, li);
trace_xfs_defer_add_item(tp->t_mountp, dfp, li);
return dfp;
}
/*
* Add a defer ops barrier to force two otherwise adjacent deferred work items
* to be tracked separately and have separate log items.
*/
void
xfs_defer_add_barrier(
struct xfs_trans *tp)
{
struct xfs_defer_pending *dfp;
ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
/* If the last defer op added was a barrier, we're done. */
dfp = xfs_defer_find_last(tp, &xfs_barrier_defer_type);
if (dfp)
return;
xfs_defer_alloc(&tp->t_dfops, &xfs_barrier_defer_type);
trace_xfs_defer_add_item(tp->t_mountp, dfp, NULL);
}
/*
* Create a pending deferred work item to replay the recovered intent item
* and add it to the list.
*/
void
xfs_defer_start_recovery(
struct xfs_log_item *lip,
struct list_head *r_dfops,
const struct xfs_defer_op_type *ops)
{
struct xfs_defer_pending *dfp = xfs_defer_alloc(r_dfops, ops);
dfp->dfp_intent = lip;
}
/*
* Cancel a deferred work item created to recover a log intent item. @dfp
* will be freed after this function returns.
*/
void
xfs_defer_cancel_recovery(
struct xfs_mount *mp,
struct xfs_defer_pending *dfp)
{
xfs_defer_pending_abort(mp, dfp);
xfs_defer_pending_cancel_work(mp, dfp);
}
/* Replay the deferred work item created from a recovered log intent item. */
int
xfs_defer_finish_recovery(
struct xfs_mount *mp,
struct xfs_defer_pending *dfp,
struct list_head *capture_list)
{
const struct xfs_defer_op_type *ops = dfp->dfp_ops;
int error;
/* dfp is freed by recover_work and must not be accessed afterwards */
error = ops->recover_work(dfp, capture_list);
if (error)
trace_xlog_intent_recovery_failed(mp, ops, error);
return error;
}
/*
* Move deferred ops from one transaction to another and reset the source to
* initial state. This is primarily used to carry state forward across
* transaction rolls with pending dfops.
*/
void
xfs_defer_move(
struct xfs_trans *dtp,
struct xfs_trans *stp)
{
list_splice_init(&stp->t_dfops, &dtp->t_dfops);
/*
* Low free space mode was historically controlled by a dfops field.
* This meant that low mode state potentially carried across multiple
* transaction rolls. Transfer low mode on a dfops move to preserve
* that behavior.
*/
dtp->t_flags |= (stp->t_flags & XFS_TRANS_LOWMODE);
stp->t_flags &= ~XFS_TRANS_LOWMODE;
}
/*
* Prepare a chain of fresh deferred ops work items to be completed later. Log
* recovery requires the ability to put off until later the actual finishing
* work so that it can process unfinished items recovered from the log in
* correct order.
*
* Create and log intent items for all the work that we're capturing so that we
* can be assured that the items will get replayed if the system goes down
* before log recovery gets a chance to finish the work it put off. The entire
* deferred ops state is transferred to the capture structure and the
* transaction is then ready for the caller to commit it. If there are no
* intent items to capture, this function returns NULL.
*
* If capture_ip is not NULL, the capture structure will obtain an extra
* reference to the inode.
*/
static struct xfs_defer_capture *
xfs_defer_ops_capture(
struct xfs_trans *tp)
{
struct xfs_defer_capture *dfc;
unsigned short i;
int error;
if (list_empty(&tp->t_dfops))
return NULL;
error = xfs_defer_create_intents(tp);
if (error < 0)
return ERR_PTR(error);
/* Create an object to capture the defer ops. */
dfc = kzalloc(sizeof(*dfc), GFP_KERNEL | __GFP_NOFAIL);
INIT_LIST_HEAD(&dfc->dfc_list);
INIT_LIST_HEAD(&dfc->dfc_dfops);
/* Move the dfops chain and transaction state to the capture struct. */
list_splice_init(&tp->t_dfops, &dfc->dfc_dfops);
dfc->dfc_tpflags = tp->t_flags & XFS_TRANS_LOWMODE;
tp->t_flags &= ~XFS_TRANS_LOWMODE;
/* Capture the remaining block reservations along with the dfops. */
dfc->dfc_blkres = tp->t_blk_res - tp->t_blk_res_used;
dfc->dfc_rtxres = tp->t_rtx_res - tp->t_rtx_res_used;
/* Preserve the log reservation size. */
dfc->dfc_logres = tp->t_log_res;
error = xfs_defer_save_resources(&dfc->dfc_held, tp);
if (error) {
/*
* Resource capture should never fail, but if it does, we
* still have to shut down the log and release things
* properly.
*/
xfs_force_shutdown(tp->t_mountp, SHUTDOWN_CORRUPT_INCORE);
}
/*
* Grab extra references to the inodes and buffers because callers are
* expected to release their held references after we commit the
* transaction.
*/
for (i = 0; i < dfc->dfc_held.dr_inos; i++) {
xfs_assert_ilocked(dfc->dfc_held.dr_ip[i], XFS_ILOCK_EXCL);
ihold(VFS_I(dfc->dfc_held.dr_ip[i]));
}
for (i = 0; i < dfc->dfc_held.dr_bufs; i++)
xfs_buf_hold(dfc->dfc_held.dr_bp[i]);
return dfc;
}
/* Release all resources that we used to capture deferred ops. */
void
xfs_defer_ops_capture_abort(
struct xfs_mount *mp,
struct xfs_defer_capture *dfc)
{
unsigned short i;
xfs_defer_pending_abort_list(mp, &dfc->dfc_dfops);
xfs_defer_cancel_list(mp, &dfc->dfc_dfops);
for (i = 0; i < dfc->dfc_held.dr_bufs; i++)
xfs_buf_relse(dfc->dfc_held.dr_bp[i]);
for (i = 0; i < dfc->dfc_held.dr_inos; i++)
xfs_irele(dfc->dfc_held.dr_ip[i]);
kfree(dfc);
}
/*
* Capture any deferred ops and commit the transaction. This is the last step
* needed to finish a log intent item that we recovered from the log. If any
* of the deferred ops operate on an inode, the caller must pass in that inode
* so that the reference can be transferred to the capture structure. The
* caller must hold ILOCK_EXCL on the inode, and must unlock it before calling
* xfs_defer_ops_continue.
*/
int
xfs_defer_ops_capture_and_commit(
struct xfs_trans *tp,
struct list_head *capture_list)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_defer_capture *dfc;
int error;
/* If we don't capture anything, commit transaction and exit. */
dfc = xfs_defer_ops_capture(tp);
if (IS_ERR(dfc)) {
xfs_trans_cancel(tp);
return PTR_ERR(dfc);
}
if (!dfc)
return xfs_trans_commit(tp);
/* Commit the transaction and add the capture structure to the list. */
error = xfs_trans_commit(tp);
if (error) {
xfs_defer_ops_capture_abort(mp, dfc);
return error;
}
list_add_tail(&dfc->dfc_list, capture_list);
return 0;
}
/*
* Attach a chain of captured deferred ops to a new transaction and free the
* capture structure. If an inode was captured, it will be passed back to the
* caller with ILOCK_EXCL held and joined to the transaction with lockflags==0.
* The caller now owns the inode reference.
*/
void
xfs_defer_ops_continue(
struct xfs_defer_capture *dfc,
struct xfs_trans *tp,
struct xfs_defer_resources *dres)
{
unsigned int i;
ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
ASSERT(!(tp->t_flags & XFS_TRANS_DIRTY));
/* Lock the captured resources to the new transaction. */
if (dfc->dfc_held.dr_inos > 2) {
xfs_sort_inodes(dfc->dfc_held.dr_ip, dfc->dfc_held.dr_inos);
xfs_lock_inodes(dfc->dfc_held.dr_ip, dfc->dfc_held.dr_inos,
XFS_ILOCK_EXCL);
} else if (dfc->dfc_held.dr_inos == 2)
xfs_lock_two_inodes(dfc->dfc_held.dr_ip[0], XFS_ILOCK_EXCL,
dfc->dfc_held.dr_ip[1], XFS_ILOCK_EXCL);
else if (dfc->dfc_held.dr_inos == 1)
xfs_ilock(dfc->dfc_held.dr_ip[0], XFS_ILOCK_EXCL);
for (i = 0; i < dfc->dfc_held.dr_bufs; i++)
xfs_buf_lock(dfc->dfc_held.dr_bp[i]);
/* Join the captured resources to the new transaction. */
xfs_defer_restore_resources(tp, &dfc->dfc_held);
memcpy(dres, &dfc->dfc_held, sizeof(struct xfs_defer_resources));
dres->dr_bufs = 0;
/* Move captured dfops chain and state to the transaction. */
list_splice_init(&dfc->dfc_dfops, &tp->t_dfops);
tp->t_flags |= dfc->dfc_tpflags;
kfree(dfc);
}
/* Release the resources captured and continued during recovery. */
void
xfs_defer_resources_rele(
struct xfs_defer_resources *dres)
{
unsigned short i;
for (i = 0; i < dres->dr_inos; i++) {
xfs_iunlock(dres->dr_ip[i], XFS_ILOCK_EXCL);
xfs_irele(dres->dr_ip[i]);
dres->dr_ip[i] = NULL;
}
for (i = 0; i < dres->dr_bufs; i++) {
xfs_buf_relse(dres->dr_bp[i]);
dres->dr_bp[i] = NULL;
}
dres->dr_inos = 0;
dres->dr_bufs = 0;
dres->dr_ordered = 0;
}
static inline int __init
xfs_defer_init_cache(void)
{
xfs_defer_pending_cache = kmem_cache_create("xfs_defer_pending",
sizeof(struct xfs_defer_pending),
0, 0, NULL);
return xfs_defer_pending_cache != NULL ? 0 : -ENOMEM;
}
static inline void
xfs_defer_destroy_cache(void)
{
kmem_cache_destroy(xfs_defer_pending_cache);
xfs_defer_pending_cache = NULL;
}
/* Set up caches for deferred work items. */
int __init
xfs_defer_init_item_caches(void)
{
int error;
error = xfs_defer_init_cache();
if (error)
return error;
error = xfs_rmap_intent_init_cache();
if (error)
goto err;
error = xfs_refcount_intent_init_cache();
if (error)
goto err;
error = xfs_bmap_intent_init_cache();
if (error)
goto err;
error = xfs_extfree_intent_init_cache();
if (error)
goto err;
error = xfs_attr_intent_init_cache();
if (error)
goto err;
error = xfs_exchmaps_intent_init_cache();
if (error)
goto err;
return 0;
err:
xfs_defer_destroy_item_caches();
return error;
}
/* Destroy all the deferred work item caches, if they've been allocated. */
void
xfs_defer_destroy_item_caches(void)
{
xfs_exchmaps_intent_destroy_cache();
xfs_attr_intent_destroy_cache();
xfs_extfree_intent_destroy_cache();
xfs_bmap_intent_destroy_cache();
xfs_refcount_intent_destroy_cache();
xfs_rmap_intent_destroy_cache();
xfs_defer_destroy_cache();
}
/*
* Mark a deferred work item so that it will be requeued indefinitely without
* being finished. Caller must ensure there are no data dependencies on this
* work item in the meantime.
*/
void
xfs_defer_item_pause(
struct xfs_trans *tp,
struct xfs_defer_pending *dfp)
{
ASSERT(!(dfp->dfp_flags & XFS_DEFER_PAUSED));
dfp->dfp_flags |= XFS_DEFER_PAUSED;
trace_xfs_defer_item_pause(tp->t_mountp, dfp);
}
/*
* Release a paused deferred work item so that it will be finished during the
* next transaction roll.
*/
void
xfs_defer_item_unpause(
struct xfs_trans *tp,
struct xfs_defer_pending *dfp)
{
ASSERT(dfp->dfp_flags & XFS_DEFER_PAUSED);
dfp->dfp_flags &= ~XFS_DEFER_PAUSED;
trace_xfs_defer_item_unpause(tp->t_mountp, dfp);
}
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