linux/fs/xfs/xfs_bmap_item.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2016 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_shared.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_bmap_item.h"
#include "xfs_log.h"
#include "xfs_bmap.h"
#include "xfs_icache.h"
#include "xfs_bmap_btree.h"
#include "xfs_trans_space.h"
#include "xfs_error.h"
#include "xfs_log_priv.h"
#include "xfs_log_recover.h"
#include "xfs_ag.h"
struct kmem_cache *xfs_bui_cache;
struct kmem_cache *xfs_bud_cache;
static const struct xfs_item_ops xfs_bui_item_ops;
static inline struct xfs_bui_log_item *BUI_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_bui_log_item, bui_item);
}
STATIC void
xfs_bui_item_free(
struct xfs_bui_log_item *buip)
{
kmem_free(buip->bui_item.li_lv_shadow);
kmem_cache_free(xfs_bui_cache, buip);
}
/*
* Freeing the BUI requires that we remove it from the AIL if it has already
* been placed there. However, the BUI may not yet have been placed in the AIL
* when called by xfs_bui_release() from BUD processing due to the ordering of
* committed vs unpin operations in bulk insert operations. Hence the reference
* count to ensure only the last caller frees the BUI.
*/
STATIC void
xfs_bui_release(
struct xfs_bui_log_item *buip)
{
ASSERT(atomic_read(&buip->bui_refcount) > 0);
if (!atomic_dec_and_test(&buip->bui_refcount))
return;
xfs_trans_ail_delete(&buip->bui_item, 0);
xfs_bui_item_free(buip);
}
STATIC void
xfs_bui_item_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
struct xfs_bui_log_item *buip = BUI_ITEM(lip);
*nvecs += 1;
*nbytes += xfs_bui_log_format_sizeof(buip->bui_format.bui_nextents);
}
/*
* This is called to fill in the vector of log iovecs for the
* given bui log item. We use only 1 iovec, and we point that
* at the bui_log_format structure embedded in the bui item.
* It is at this point that we assert that all of the extent
* slots in the bui item have been filled.
*/
STATIC void
xfs_bui_item_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_bui_log_item *buip = BUI_ITEM(lip);
struct xfs_log_iovec *vecp = NULL;
ASSERT(atomic_read(&buip->bui_next_extent) ==
buip->bui_format.bui_nextents);
buip->bui_format.bui_type = XFS_LI_BUI;
buip->bui_format.bui_size = 1;
xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_BUI_FORMAT, &buip->bui_format,
xfs_bui_log_format_sizeof(buip->bui_format.bui_nextents));
}
/*
* The unpin operation is the last place an BUI is manipulated in the log. It is
* either inserted in the AIL or aborted in the event of a log I/O error. In
* either case, the BUI transaction has been successfully committed to make it
* this far. Therefore, we expect whoever committed the BUI to either construct
* and commit the BUD or drop the BUD's reference in the event of error. Simply
* drop the log's BUI reference now that the log is done with it.
*/
STATIC void
xfs_bui_item_unpin(
struct xfs_log_item *lip,
int remove)
{
struct xfs_bui_log_item *buip = BUI_ITEM(lip);
xfs_bui_release(buip);
}
/*
* The BUI has been either committed or aborted if the transaction has been
* cancelled. If the transaction was cancelled, an BUD isn't going to be
* constructed and thus we free the BUI here directly.
*/
STATIC void
xfs: split iop_unlock The iop_unlock method is called when comitting or cancelling a transaction. In the latter case, the transaction may or may not be aborted. While there is no known problem with the current code in practice, this implementation is limited in that any log item implementation that might want to differentiate between a commit and a cancellation must rely on the aborted state. The aborted bit is only set when the cancelled transaction is dirty, however. This means that there is no way to distinguish between a commit and a clean transaction cancellation. For example, intent log items currently rely on this distinction. The log item is either transferred to the CIL on commit or released on transaction cancel. There is currently no possibility for a clean intent log item in a transaction, but if that state is ever introduced a cancel of such a transaction will immediately result in memory leaks of the associated log item(s). This is an interface deficiency and landmine. To clean this up, replace the iop_unlock method with an iop_release method that is specific to transaction cancel. The existing iop_committing method occurs at the same time as iop_unlock in the commit path and there is no need for two separate callbacks here. Overload the iop_committing method with the current commit time iop_unlock implementations to eliminate the need for the latter and further simplify the interface. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-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>
2019-06-29 10:27:32 +08:00
xfs_bui_item_release(
struct xfs_log_item *lip)
{
xfs: split iop_unlock The iop_unlock method is called when comitting or cancelling a transaction. In the latter case, the transaction may or may not be aborted. While there is no known problem with the current code in practice, this implementation is limited in that any log item implementation that might want to differentiate between a commit and a cancellation must rely on the aborted state. The aborted bit is only set when the cancelled transaction is dirty, however. This means that there is no way to distinguish between a commit and a clean transaction cancellation. For example, intent log items currently rely on this distinction. The log item is either transferred to the CIL on commit or released on transaction cancel. There is currently no possibility for a clean intent log item in a transaction, but if that state is ever introduced a cancel of such a transaction will immediately result in memory leaks of the associated log item(s). This is an interface deficiency and landmine. To clean this up, replace the iop_unlock method with an iop_release method that is specific to transaction cancel. The existing iop_committing method occurs at the same time as iop_unlock in the commit path and there is no need for two separate callbacks here. Overload the iop_committing method with the current commit time iop_unlock implementations to eliminate the need for the latter and further simplify the interface. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-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>
2019-06-29 10:27:32 +08:00
xfs_bui_release(BUI_ITEM(lip));
}
/*
* Allocate and initialize an bui item with the given number of extents.
*/
STATIC struct xfs_bui_log_item *
xfs_bui_init(
struct xfs_mount *mp)
{
struct xfs_bui_log_item *buip;
buip = kmem_cache_zalloc(xfs_bui_cache, GFP_KERNEL | __GFP_NOFAIL);
xfs_log_item_init(mp, &buip->bui_item, XFS_LI_BUI, &xfs_bui_item_ops);
buip->bui_format.bui_nextents = XFS_BUI_MAX_FAST_EXTENTS;
buip->bui_format.bui_id = (uintptr_t)(void *)buip;
atomic_set(&buip->bui_next_extent, 0);
atomic_set(&buip->bui_refcount, 2);
return buip;
}
static inline struct xfs_bud_log_item *BUD_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_bud_log_item, bud_item);
}
STATIC void
xfs_bud_item_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
*nvecs += 1;
*nbytes += sizeof(struct xfs_bud_log_format);
}
/*
* This is called to fill in the vector of log iovecs for the
* given bud log item. We use only 1 iovec, and we point that
* at the bud_log_format structure embedded in the bud item.
* It is at this point that we assert that all of the extent
* slots in the bud item have been filled.
*/
STATIC void
xfs_bud_item_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_bud_log_item *budp = BUD_ITEM(lip);
struct xfs_log_iovec *vecp = NULL;
budp->bud_format.bud_type = XFS_LI_BUD;
budp->bud_format.bud_size = 1;
xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_BUD_FORMAT, &budp->bud_format,
sizeof(struct xfs_bud_log_format));
}
/*
* The BUD is either committed or aborted if the transaction is cancelled. If
* the transaction is cancelled, drop our reference to the BUI and free the
* BUD.
*/
STATIC void
xfs: split iop_unlock The iop_unlock method is called when comitting or cancelling a transaction. In the latter case, the transaction may or may not be aborted. While there is no known problem with the current code in practice, this implementation is limited in that any log item implementation that might want to differentiate between a commit and a cancellation must rely on the aborted state. The aborted bit is only set when the cancelled transaction is dirty, however. This means that there is no way to distinguish between a commit and a clean transaction cancellation. For example, intent log items currently rely on this distinction. The log item is either transferred to the CIL on commit or released on transaction cancel. There is currently no possibility for a clean intent log item in a transaction, but if that state is ever introduced a cancel of such a transaction will immediately result in memory leaks of the associated log item(s). This is an interface deficiency and landmine. To clean this up, replace the iop_unlock method with an iop_release method that is specific to transaction cancel. The existing iop_committing method occurs at the same time as iop_unlock in the commit path and there is no need for two separate callbacks here. Overload the iop_committing method with the current commit time iop_unlock implementations to eliminate the need for the latter and further simplify the interface. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-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>
2019-06-29 10:27:32 +08:00
xfs_bud_item_release(
struct xfs_log_item *lip)
{
struct xfs_bud_log_item *budp = BUD_ITEM(lip);
xfs: split iop_unlock The iop_unlock method is called when comitting or cancelling a transaction. In the latter case, the transaction may or may not be aborted. While there is no known problem with the current code in practice, this implementation is limited in that any log item implementation that might want to differentiate between a commit and a cancellation must rely on the aborted state. The aborted bit is only set when the cancelled transaction is dirty, however. This means that there is no way to distinguish between a commit and a clean transaction cancellation. For example, intent log items currently rely on this distinction. The log item is either transferred to the CIL on commit or released on transaction cancel. There is currently no possibility for a clean intent log item in a transaction, but if that state is ever introduced a cancel of such a transaction will immediately result in memory leaks of the associated log item(s). This is an interface deficiency and landmine. To clean this up, replace the iop_unlock method with an iop_release method that is specific to transaction cancel. The existing iop_committing method occurs at the same time as iop_unlock in the commit path and there is no need for two separate callbacks here. Overload the iop_committing method with the current commit time iop_unlock implementations to eliminate the need for the latter and further simplify the interface. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-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>
2019-06-29 10:27:32 +08:00
xfs_bui_release(budp->bud_buip);
kmem_free(budp->bud_item.li_lv_shadow);
kmem_cache_free(xfs_bud_cache, budp);
}
static struct xfs_log_item *
xfs_bud_item_intent(
struct xfs_log_item *lip)
{
return &BUD_ITEM(lip)->bud_buip->bui_item;
}
static const struct xfs_item_ops xfs_bud_item_ops = {
.flags = XFS_ITEM_RELEASE_WHEN_COMMITTED |
XFS_ITEM_INTENT_DONE,
.iop_size = xfs_bud_item_size,
.iop_format = xfs_bud_item_format,
xfs: split iop_unlock The iop_unlock method is called when comitting or cancelling a transaction. In the latter case, the transaction may or may not be aborted. While there is no known problem with the current code in practice, this implementation is limited in that any log item implementation that might want to differentiate between a commit and a cancellation must rely on the aborted state. The aborted bit is only set when the cancelled transaction is dirty, however. This means that there is no way to distinguish between a commit and a clean transaction cancellation. For example, intent log items currently rely on this distinction. The log item is either transferred to the CIL on commit or released on transaction cancel. There is currently no possibility for a clean intent log item in a transaction, but if that state is ever introduced a cancel of such a transaction will immediately result in memory leaks of the associated log item(s). This is an interface deficiency and landmine. To clean this up, replace the iop_unlock method with an iop_release method that is specific to transaction cancel. The existing iop_committing method occurs at the same time as iop_unlock in the commit path and there is no need for two separate callbacks here. Overload the iop_committing method with the current commit time iop_unlock implementations to eliminate the need for the latter and further simplify the interface. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-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>
2019-06-29 10:27:32 +08:00
.iop_release = xfs_bud_item_release,
.iop_intent = xfs_bud_item_intent,
};
/* Sort bmap intents by inode. */
static int
xfs_bmap_update_diff_items(
void *priv,
const struct list_head *a,
const struct list_head *b)
{
struct xfs_bmap_intent *ba;
struct xfs_bmap_intent *bb;
ba = container_of(a, struct xfs_bmap_intent, bi_list);
bb = container_of(b, struct xfs_bmap_intent, bi_list);
return ba->bi_owner->i_ino - bb->bi_owner->i_ino;
}
/* Set the map extent flags for this mapping. */
static void
xfs_trans_set_bmap_flags(
struct xfs_map_extent *map,
enum xfs_bmap_intent_type type,
int whichfork,
xfs_exntst_t state)
{
map->me_flags = 0;
switch (type) {
case XFS_BMAP_MAP:
case XFS_BMAP_UNMAP:
map->me_flags = type;
break;
default:
ASSERT(0);
}
if (state == XFS_EXT_UNWRITTEN)
map->me_flags |= XFS_BMAP_EXTENT_UNWRITTEN;
if (whichfork == XFS_ATTR_FORK)
map->me_flags |= XFS_BMAP_EXTENT_ATTR_FORK;
}
/* Log bmap updates in the intent item. */
STATIC void
xfs_bmap_update_log_item(
struct xfs_trans *tp,
struct xfs_bui_log_item *buip,
struct xfs_bmap_intent *bi)
{
uint next_extent;
struct xfs_map_extent *map;
/*
* atomic_inc_return gives us the value after the increment;
* we want to use it as an array index so we need to subtract 1 from
* it.
*/
next_extent = atomic_inc_return(&buip->bui_next_extent) - 1;
ASSERT(next_extent < buip->bui_format.bui_nextents);
map = &buip->bui_format.bui_extents[next_extent];
map->me_owner = bi->bi_owner->i_ino;
map->me_startblock = bi->bi_bmap.br_startblock;
map->me_startoff = bi->bi_bmap.br_startoff;
map->me_len = bi->bi_bmap.br_blockcount;
xfs_trans_set_bmap_flags(map, bi->bi_type, bi->bi_whichfork,
bi->bi_bmap.br_state);
}
static struct xfs_log_item *
xfs_bmap_update_create_intent(
struct xfs_trans *tp,
struct list_head *items,
unsigned int count,
bool sort)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_bui_log_item *buip = xfs_bui_init(mp);
struct xfs_bmap_intent *bi;
ASSERT(count == XFS_BUI_MAX_FAST_EXTENTS);
if (sort)
list_sort(mp, items, xfs_bmap_update_diff_items);
list_for_each_entry(bi, items, bi_list)
xfs_bmap_update_log_item(tp, buip, bi);
return &buip->bui_item;
}
/* Get an BUD so we can process all the deferred bmap updates. */
static struct xfs_log_item *
xfs_bmap_update_create_done(
struct xfs_trans *tp,
struct xfs_log_item *intent,
unsigned int count)
{
struct xfs_bui_log_item *buip = BUI_ITEM(intent);
struct xfs_bud_log_item *budp;
budp = kmem_cache_zalloc(xfs_bud_cache, GFP_KERNEL | __GFP_NOFAIL);
xfs_log_item_init(tp->t_mountp, &budp->bud_item, XFS_LI_BUD,
&xfs_bud_item_ops);
budp->bud_buip = buip;
budp->bud_format.bud_bui_id = buip->bui_format.bui_id;
return &budp->bud_item;
}
/* Take a passive ref to the AG containing the space we're mapping. */
void
xfs_bmap_update_get_group(
struct xfs_mount *mp,
struct xfs_bmap_intent *bi)
{
xfs_agnumber_t agno;
agno = XFS_FSB_TO_AGNO(mp, bi->bi_bmap.br_startblock);
xfs: allow queued AG intents to drain before scrubbing When a writer thread executes a chain of log intent items, the AG header buffer locks will cycle during a transaction roll to get from one intent item to the next in a chain. Although scrub takes all AG header buffer locks, this isn't sufficient to guard against scrub checking an AG while that writer thread is in the middle of finishing a chain because there's no higher level locking primitive guarding allocation groups. When there's a collision, cross-referencing between data structures (e.g. rmapbt and refcountbt) yields false corruption events; if repair is running, this results in incorrect repairs, which is catastrophic. Fix this by adding to the perag structure the count of active intents and make scrub wait until it has both AG header buffer locks and the intent counter reaches zero. One quirk of the drain code is that deferred bmap updates also bump and drop the intent counter. A fundamental decision made during the design phase of the reverse mapping feature is that updates to the rmapbt records are always made by the same code that updates the primary metadata. In other words, callers of bmapi functions expect that the bmapi functions will queue deferred rmap updates. Some parts of the reflink code queue deferred refcount (CUI) and bmap (BUI) updates in the same head transaction, but the deferred work manager completely finishes the CUI before the BUI work is started. As a result, the CUI drops the intent count long before the deferred rmap (RUI) update even has a chance to bump the intent count. The only way to keep the intent count elevated between the CUI and RUI is for the BUI to bump the counter until the RUI has been created. A second quirk of the intent drain code is that deferred work items must increment the intent counter as soon as the work item is added to the transaction. When a BUI completes and queues an RUI, the RUI must increment the counter before the BUI decrements it. The only way to accomplish this is to require that the counter be bumped as soon as the deferred work item is created in memory. In the next patches we'll improve on this facility, but this patch provides the basic functionality. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-12 09:59:58 +08:00
/*
* Bump the intent count on behalf of the deferred rmap and refcount
* intent items that that we can queue when we finish this bmap work.
* This new intent item will bump the intent count before the bmap
* intent drops the intent count, ensuring that the intent count
* remains nonzero across the transaction roll.
*/
bi->bi_pag = xfs_perag_intent_get(mp, agno);
}
/* Release a passive AG ref after finishing mapping work. */
static inline void
xfs_bmap_update_put_group(
struct xfs_bmap_intent *bi)
{
xfs: allow queued AG intents to drain before scrubbing When a writer thread executes a chain of log intent items, the AG header buffer locks will cycle during a transaction roll to get from one intent item to the next in a chain. Although scrub takes all AG header buffer locks, this isn't sufficient to guard against scrub checking an AG while that writer thread is in the middle of finishing a chain because there's no higher level locking primitive guarding allocation groups. When there's a collision, cross-referencing between data structures (e.g. rmapbt and refcountbt) yields false corruption events; if repair is running, this results in incorrect repairs, which is catastrophic. Fix this by adding to the perag structure the count of active intents and make scrub wait until it has both AG header buffer locks and the intent counter reaches zero. One quirk of the drain code is that deferred bmap updates also bump and drop the intent counter. A fundamental decision made during the design phase of the reverse mapping feature is that updates to the rmapbt records are always made by the same code that updates the primary metadata. In other words, callers of bmapi functions expect that the bmapi functions will queue deferred rmap updates. Some parts of the reflink code queue deferred refcount (CUI) and bmap (BUI) updates in the same head transaction, but the deferred work manager completely finishes the CUI before the BUI work is started. As a result, the CUI drops the intent count long before the deferred rmap (RUI) update even has a chance to bump the intent count. The only way to keep the intent count elevated between the CUI and RUI is for the BUI to bump the counter until the RUI has been created. A second quirk of the intent drain code is that deferred work items must increment the intent counter as soon as the work item is added to the transaction. When a BUI completes and queues an RUI, the RUI must increment the counter before the BUI decrements it. The only way to accomplish this is to require that the counter be bumped as soon as the deferred work item is created in memory. In the next patches we'll improve on this facility, but this patch provides the basic functionality. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-12 09:59:58 +08:00
xfs_perag_intent_put(bi->bi_pag);
}
/* Process a deferred bmap update. */
STATIC int
xfs_bmap_update_finish_item(
struct xfs_trans *tp,
struct xfs_log_item *done,
struct list_head *item,
struct xfs_btree_cur **state)
{
struct xfs_bmap_intent *bi;
int error;
bi = container_of(item, struct xfs_bmap_intent, bi_list);
error = xfs_bmap_finish_one(tp, bi);
if (!error && bi->bi_bmap.br_blockcount > 0) {
ASSERT(bi->bi_type == XFS_BMAP_UNMAP);
return -EAGAIN;
}
xfs_bmap_update_put_group(bi);
kmem_cache_free(xfs_bmap_intent_cache, bi);
return error;
}
/* Abort all pending BUIs. */
STATIC void
xfs_bmap_update_abort_intent(
struct xfs_log_item *intent)
{
xfs_bui_release(BUI_ITEM(intent));
}
/* Cancel a deferred bmap update. */
STATIC void
xfs_bmap_update_cancel_item(
struct list_head *item)
{
struct xfs_bmap_intent *bi;
bi = container_of(item, struct xfs_bmap_intent, bi_list);
xfs_bmap_update_put_group(bi);
kmem_cache_free(xfs_bmap_intent_cache, bi);
}
/* Is this recovered BUI ok? */
static inline bool
xfs_bui_validate(
struct xfs_mount *mp,
struct xfs_bui_log_item *buip)
{
struct xfs_map_extent *map;
/* Only one mapping operation per BUI... */
if (buip->bui_format.bui_nextents != XFS_BUI_MAX_FAST_EXTENTS)
return false;
map = &buip->bui_format.bui_extents[0];
if (map->me_flags & ~XFS_BMAP_EXTENT_FLAGS)
return false;
switch (map->me_flags & XFS_BMAP_EXTENT_TYPE_MASK) {
case XFS_BMAP_MAP:
case XFS_BMAP_UNMAP:
break;
default:
return false;
}
if (!xfs_verify_ino(mp, map->me_owner))
return false;
if (!xfs_verify_fileext(mp, map->me_startoff, map->me_len))
return false;
return xfs_verify_fsbext(mp, map->me_startblock, map->me_len);
}
static inline struct xfs_bmap_intent *
xfs_bui_recover_work(
struct xfs_mount *mp,
struct xfs_defer_pending *dfp,
struct xfs_inode **ipp,
struct xfs_map_extent *map)
{
struct xfs_bmap_intent *bi;
int error;
error = xlog_recover_iget(mp, map->me_owner, ipp);
if (error)
return ERR_PTR(error);
bi = kmem_cache_zalloc(xfs_bmap_intent_cache, GFP_NOFS | __GFP_NOFAIL);
bi->bi_whichfork = (map->me_flags & XFS_BMAP_EXTENT_ATTR_FORK) ?
XFS_ATTR_FORK : XFS_DATA_FORK;
bi->bi_type = map->me_flags & XFS_BMAP_EXTENT_TYPE_MASK;
bi->bi_bmap.br_startblock = map->me_startblock;
bi->bi_bmap.br_startoff = map->me_startoff;
bi->bi_bmap.br_blockcount = map->me_len;
bi->bi_bmap.br_state = (map->me_flags & XFS_BMAP_EXTENT_UNWRITTEN) ?
XFS_EXT_UNWRITTEN : XFS_EXT_NORM;
bi->bi_owner = *ipp;
xfs_bmap_update_get_group(mp, bi);
xfs_defer_add_item(dfp, &bi->bi_list);
return bi;
}
/*
* Process a bmap update intent item that was recovered from the log.
* We need to update some inode's bmbt.
*/
STATIC int
xfs_bmap_recover_work(
struct xfs_defer_pending *dfp,
xfs: proper replay of deferred ops queued during log recovery When we replay unfinished intent items that have been recovered from the log, it's possible that the replay will cause the creation of more deferred work items. As outlined in commit 509955823cc9c ("xfs: log recovery should replay deferred ops in order"), later work items have an implicit ordering dependency on earlier work items. Therefore, recovery must replay the items (both recovered and created) in the same order that they would have been during normal operation. For log recovery, we enforce this ordering by using an empty transaction to collect deferred ops that get created in the process of recovering a log intent item to prevent them from being committed before the rest of the recovered intent items. After we finish committing all the recovered log items, we allocate a transaction with an enormous block reservation, splice our huge list of created deferred ops into that transaction, and commit it, thereby finishing all those ops. This is /really/ hokey -- it's the one place in XFS where we allow nested transactions; the splicing of the defer ops list is is inelegant and has to be done twice per recovery function; and the broken way we handle inode pointers and block reservations cause subtle use-after-free and allocator problems that will be fixed by this patch and the two patches after it. Therefore, replace the hokey empty transaction with a structure designed to capture each chain of deferred ops that are created as part of recovering a single unfinished log intent. Finally, refactor the loop that replays those chains to do so using one transaction per chain. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-09-26 08:39:37 +08:00
struct list_head *capture_list)
{
xfs: reserve less log space when recovering log intent items Wengang Wang reports that a customer's system was running a number of truncate operations on a filesystem with a very small log. Contention on the reserve heads lead to other threads stalling on smaller updates (e.g. mtime updates) long enough to result in the node being rebooted on account of the lack of responsivenes. The node failed to recover because log recovery of an EFI became stuck waiting for a grant of reserve space. From Wengang's report: "For the file deletion, log bytes are reserved basing on xfs_mount->tr_itruncate which is: tr_logres = 175488, tr_logcount = 2, tr_logflags = XFS_TRANS_PERM_LOG_RES, "You see it's a permanent log reservation with two log operations (two transactions in rolling mode). After calculation (xlog_calc_unit_res() adds space for various log headers), the final log space needed per transaction changes from 175488 to 180208 bytes. So the total log space needed is 360416 bytes (180208 * 2). [That quantity] of log space (360416 bytes) needs to be reserved for both run time inode removing (xfs_inactive_truncate()) and EFI recover (xfs_efi_item_recover())." In other words, runtime pre-reserves 360K of space in anticipation of running a chain of two transactions in which each transaction gets a 180K reservation. Now that we've allocated the transaction, we delete the bmap mapping, log an EFI to free the space, and roll the transaction as part of finishing the deferops chain. Rolling creates a new xfs_trans which shares its ticket with the old transaction. Next, xfs_trans_roll calls __xfs_trans_commit with regrant == true, which calls xlog_cil_commit with the same regrant parameter. xlog_cil_commit calls xfs_log_ticket_regrant, which decrements t_cnt and subtracts t_curr_res from the reservation and write heads. If the filesystem is fresh and the first transaction only used (say) 20K, then t_curr_res will be 160K, and we give that much reservation back to the reservation head. Or if the file is really fragmented and the first transaction actually uses 170K, then t_curr_res will be 10K, and that's what we give back to the reservation. Having done that, we're now headed into the second transaction with an EFI and 180K of reservation. Other threads apparently consumed all the reservation for smaller transactions, such as timestamp updates. Now let's say the first transaction gets written to disk and we crash without ever completing the second transaction. Now we remount the fs, log recovery finds the unfinished EFI, and calls xfs_efi_recover to finish the EFI. However, xfs_efi_recover starts a new tr_itruncate tranasction, which asks for 360K log reservation. This is a lot more than the 180K that we had reserved at the time of the crash. If the first EFI to be recovered is also pinning the tail of the log, we will be unable to free any space in the log, and recovery livelocks. Wengang confirmed this: "Now we have the second transaction which has 180208 log bytes reserved too. The second transaction is supposed to process intents including extent freeing. With my hacking patch, I blocked the extent freeing 5 hours. So in that 5 hours, 180208 (NOT 360416) log bytes are reserved. "With my test case, other transactions (update timestamps) then happen. As my hacking patch pins the journal tail, those timestamp-updating transactions finally use up (almost) all the left available log space (in memory in on disk). And finally the on disk (and in memory) available log space goes down near to 180208 bytes. Those 180208 bytes are reserved by [the] second (extent-free) transaction [in the chain]." Wengang and I noticed that EFI recovery starts a transaction, completes one step of the chain, and commits the transaction without completing any other steps of the chain. Those subsequent steps are completed by xlog_finish_defer_ops, which allocates yet another transaction to finish the rest of the chain. That transaction gets the same tr_logres as the head transaction, but with tr_logcount = 1 to force regranting with every roll to avoid livelocks. In other words, we already figured this out in commit 929b92f64048d ("xfs: xfs_defer_capture should absorb remaining transaction reservation"), but should have applied that logic to each intent item's recovery function. For Wengang's case, the xfs_trans_alloc call in the EFI recovery function should only be asking for a single transaction's worth of log reservation -- 180K, not 360K. Quoting Wengang again: "With log recovery, during EFI recovery, we use tr_itruncate again to reserve two transactions that needs 360416 log bytes. Reserving 360416 bytes fails [stalls] because we now only have about 180208 available. "Actually during the EFI recover, we only need one transaction to free the extents just like the 2nd transaction at RUNTIME. So it only needs to reserve 180208 rather than 360416 bytes. We have (a bit) more than 180208 available log bytes on disk, so [if we decrease the reservation to 180K] the reservation goes and the recovery [finishes]. That is to say: we can fix the log recover part to fix the issue. We can introduce a new xfs_trans_res xfs_mount->tr_ext_free { tr_logres = 175488, tr_logcount = 0, tr_logflags = 0, } "and use tr_ext_free instead of tr_itruncate in EFI recover." However, I don't think it quite makes sense to create an entirely new transaction reservation type to handle single-stepping during log recovery. Instead, we should copy the transaction reservation information in the xfs_mount, change tr_logcount to 1, and pass that into xfs_trans_alloc. We know this won't risk changing the min log size computation since we always ask for a fraction of the reservation for all known transaction types. This looks like it's been lurking in the codebase since commit 3d3c8b5222b92, which changed the xfs_trans_reserve call in xlog_recover_process_efi to use the tr_logcount in tr_itruncate. That changed the EFI recovery transaction from making a non-XFS_TRANS_PERM_LOG_RES request for one transaction's worth of log space to a XFS_TRANS_PERM_LOG_RES request for two transactions worth. Fixes: 3d3c8b5222b92 ("xfs: refactor xfs_trans_reserve() interface") Complements: 929b92f64048d ("xfs: xfs_defer_capture should absorb remaining transaction reservation") Suggested-by: Wengang Wang <wen.gang.wang@oracle.com> Cc: Srikanth C S <srikanth.c.s@oracle.com> [djwong: apply the same transformation to all log intent recovery] Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-09-11 23:39:05 +08:00
struct xfs_trans_res resv;
struct xfs_log_item *lip = dfp->dfp_intent;
struct xfs_bui_log_item *buip = BUI_ITEM(lip);
struct xfs_trans *tp;
struct xfs_inode *ip = NULL;
struct xfs_mount *mp = lip->li_log->l_mp;
struct xfs_map_extent *map;
struct xfs_bmap_intent *work;
int iext_delta;
int error = 0;
if (!xfs_bui_validate(mp, buip)) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
&buip->bui_format, sizeof(buip->bui_format));
return -EFSCORRUPTED;
}
map = &buip->bui_format.bui_extents[0];
work = xfs_bui_recover_work(mp, dfp, &ip, map);
if (IS_ERR(work))
return PTR_ERR(work);
/* Allocate transaction and do the work. */
xfs: reserve less log space when recovering log intent items Wengang Wang reports that a customer's system was running a number of truncate operations on a filesystem with a very small log. Contention on the reserve heads lead to other threads stalling on smaller updates (e.g. mtime updates) long enough to result in the node being rebooted on account of the lack of responsivenes. The node failed to recover because log recovery of an EFI became stuck waiting for a grant of reserve space. From Wengang's report: "For the file deletion, log bytes are reserved basing on xfs_mount->tr_itruncate which is: tr_logres = 175488, tr_logcount = 2, tr_logflags = XFS_TRANS_PERM_LOG_RES, "You see it's a permanent log reservation with two log operations (two transactions in rolling mode). After calculation (xlog_calc_unit_res() adds space for various log headers), the final log space needed per transaction changes from 175488 to 180208 bytes. So the total log space needed is 360416 bytes (180208 * 2). [That quantity] of log space (360416 bytes) needs to be reserved for both run time inode removing (xfs_inactive_truncate()) and EFI recover (xfs_efi_item_recover())." In other words, runtime pre-reserves 360K of space in anticipation of running a chain of two transactions in which each transaction gets a 180K reservation. Now that we've allocated the transaction, we delete the bmap mapping, log an EFI to free the space, and roll the transaction as part of finishing the deferops chain. Rolling creates a new xfs_trans which shares its ticket with the old transaction. Next, xfs_trans_roll calls __xfs_trans_commit with regrant == true, which calls xlog_cil_commit with the same regrant parameter. xlog_cil_commit calls xfs_log_ticket_regrant, which decrements t_cnt and subtracts t_curr_res from the reservation and write heads. If the filesystem is fresh and the first transaction only used (say) 20K, then t_curr_res will be 160K, and we give that much reservation back to the reservation head. Or if the file is really fragmented and the first transaction actually uses 170K, then t_curr_res will be 10K, and that's what we give back to the reservation. Having done that, we're now headed into the second transaction with an EFI and 180K of reservation. Other threads apparently consumed all the reservation for smaller transactions, such as timestamp updates. Now let's say the first transaction gets written to disk and we crash without ever completing the second transaction. Now we remount the fs, log recovery finds the unfinished EFI, and calls xfs_efi_recover to finish the EFI. However, xfs_efi_recover starts a new tr_itruncate tranasction, which asks for 360K log reservation. This is a lot more than the 180K that we had reserved at the time of the crash. If the first EFI to be recovered is also pinning the tail of the log, we will be unable to free any space in the log, and recovery livelocks. Wengang confirmed this: "Now we have the second transaction which has 180208 log bytes reserved too. The second transaction is supposed to process intents including extent freeing. With my hacking patch, I blocked the extent freeing 5 hours. So in that 5 hours, 180208 (NOT 360416) log bytes are reserved. "With my test case, other transactions (update timestamps) then happen. As my hacking patch pins the journal tail, those timestamp-updating transactions finally use up (almost) all the left available log space (in memory in on disk). And finally the on disk (and in memory) available log space goes down near to 180208 bytes. Those 180208 bytes are reserved by [the] second (extent-free) transaction [in the chain]." Wengang and I noticed that EFI recovery starts a transaction, completes one step of the chain, and commits the transaction without completing any other steps of the chain. Those subsequent steps are completed by xlog_finish_defer_ops, which allocates yet another transaction to finish the rest of the chain. That transaction gets the same tr_logres as the head transaction, but with tr_logcount = 1 to force regranting with every roll to avoid livelocks. In other words, we already figured this out in commit 929b92f64048d ("xfs: xfs_defer_capture should absorb remaining transaction reservation"), but should have applied that logic to each intent item's recovery function. For Wengang's case, the xfs_trans_alloc call in the EFI recovery function should only be asking for a single transaction's worth of log reservation -- 180K, not 360K. Quoting Wengang again: "With log recovery, during EFI recovery, we use tr_itruncate again to reserve two transactions that needs 360416 log bytes. Reserving 360416 bytes fails [stalls] because we now only have about 180208 available. "Actually during the EFI recover, we only need one transaction to free the extents just like the 2nd transaction at RUNTIME. So it only needs to reserve 180208 rather than 360416 bytes. We have (a bit) more than 180208 available log bytes on disk, so [if we decrease the reservation to 180K] the reservation goes and the recovery [finishes]. That is to say: we can fix the log recover part to fix the issue. We can introduce a new xfs_trans_res xfs_mount->tr_ext_free { tr_logres = 175488, tr_logcount = 0, tr_logflags = 0, } "and use tr_ext_free instead of tr_itruncate in EFI recover." However, I don't think it quite makes sense to create an entirely new transaction reservation type to handle single-stepping during log recovery. Instead, we should copy the transaction reservation information in the xfs_mount, change tr_logcount to 1, and pass that into xfs_trans_alloc. We know this won't risk changing the min log size computation since we always ask for a fraction of the reservation for all known transaction types. This looks like it's been lurking in the codebase since commit 3d3c8b5222b92, which changed the xfs_trans_reserve call in xlog_recover_process_efi to use the tr_logcount in tr_itruncate. That changed the EFI recovery transaction from making a non-XFS_TRANS_PERM_LOG_RES request for one transaction's worth of log space to a XFS_TRANS_PERM_LOG_RES request for two transactions worth. Fixes: 3d3c8b5222b92 ("xfs: refactor xfs_trans_reserve() interface") Complements: 929b92f64048d ("xfs: xfs_defer_capture should absorb remaining transaction reservation") Suggested-by: Wengang Wang <wen.gang.wang@oracle.com> Cc: Srikanth C S <srikanth.c.s@oracle.com> [djwong: apply the same transformation to all log intent recovery] Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-09-11 23:39:05 +08:00
resv = xlog_recover_resv(&M_RES(mp)->tr_itruncate);
error = xfs_trans_alloc(mp, &resv,
XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK), 0, 0, &tp);
if (error)
goto err_rele;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
if (work->bi_type == XFS_BMAP_MAP)
iext_delta = XFS_IEXT_ADD_NOSPLIT_CNT;
else
iext_delta = XFS_IEXT_PUNCH_HOLE_CNT;
error = xfs_iext_count_may_overflow(ip, work->bi_whichfork, iext_delta);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip, iext_delta);
if (error)
goto err_cancel;
error = xlog_recover_finish_intent(tp, dfp);
if (error == -EFSCORRUPTED)
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
&buip->bui_format, sizeof(buip->bui_format));
if (error)
goto err_cancel;
/*
* Commit transaction, which frees the transaction and saves the inode
* for later replay activities.
*/
error = xfs_defer_ops_capture_and_commit(tp, capture_list);
if (error)
goto err_unlock;
xfs_iunlock(ip, XFS_ILOCK_EXCL);
xfs_irele(ip);
return 0;
err_cancel:
xfs_trans_cancel(tp);
err_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
err_rele:
xfs_irele(ip);
return error;
}
xfs: periodically relog deferred intent items There's a subtle design flaw in the deferred log item code that can lead to pinning the log tail. Taking up the defer ops chain examples from the previous commit, we can get trapped in sequences like this: Caller hands us a transaction t0 with D0-D3 attached. The defer ops chain will look like the following if the transaction rolls succeed: t1: D0(t0), D1(t0), D2(t0), D3(t0) t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0) t3: d5(t1), D1(t0), D2(t0), D3(t0) ... t9: d9(t7), D3(t0) t10: D3(t0) t11: d10(t10), d11(t10) t12: d11(t10) In transaction 9, we finish d9 and try to roll to t10 while holding onto an intent item for D3 that we logged in t0. The previous commit changed the order in which we place new defer ops in the defer ops processing chain to reduce the maximum chain length. Now make xfs_defer_finish_noroll capable of relogging the entire chain periodically so that we can always move the log tail forward. Most chains will never get relogged, except for operations that generate very long chains (large extents containing many blocks with different sharing levels) or are on filesystems with small logs and a lot of ongoing metadata updates. Callers are now required to ensure that the transaction reservation is large enough to handle logging done items and new intent items for the maximum possible chain length. Most callers are careful to keep the chain lengths low, so the overhead should be minimal. The decision to relog an intent item is made based on whether the intent was logged in a previous checkpoint, since there's no point in relogging an intent into the same checkpoint. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-28 07:18:13 +08:00
/* Relog an intent item to push the log tail forward. */
static struct xfs_log_item *
xfs_bmap_relog_intent(
struct xfs_trans *tp,
xfs: periodically relog deferred intent items There's a subtle design flaw in the deferred log item code that can lead to pinning the log tail. Taking up the defer ops chain examples from the previous commit, we can get trapped in sequences like this: Caller hands us a transaction t0 with D0-D3 attached. The defer ops chain will look like the following if the transaction rolls succeed: t1: D0(t0), D1(t0), D2(t0), D3(t0) t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0) t3: d5(t1), D1(t0), D2(t0), D3(t0) ... t9: d9(t7), D3(t0) t10: D3(t0) t11: d10(t10), d11(t10) t12: d11(t10) In transaction 9, we finish d9 and try to roll to t10 while holding onto an intent item for D3 that we logged in t0. The previous commit changed the order in which we place new defer ops in the defer ops processing chain to reduce the maximum chain length. Now make xfs_defer_finish_noroll capable of relogging the entire chain periodically so that we can always move the log tail forward. Most chains will never get relogged, except for operations that generate very long chains (large extents containing many blocks with different sharing levels) or are on filesystems with small logs and a lot of ongoing metadata updates. Callers are now required to ensure that the transaction reservation is large enough to handle logging done items and new intent items for the maximum possible chain length. Most callers are careful to keep the chain lengths low, so the overhead should be minimal. The decision to relog an intent item is made based on whether the intent was logged in a previous checkpoint, since there's no point in relogging an intent into the same checkpoint. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-28 07:18:13 +08:00
struct xfs_log_item *intent,
struct xfs_log_item *done_item)
xfs: periodically relog deferred intent items There's a subtle design flaw in the deferred log item code that can lead to pinning the log tail. Taking up the defer ops chain examples from the previous commit, we can get trapped in sequences like this: Caller hands us a transaction t0 with D0-D3 attached. The defer ops chain will look like the following if the transaction rolls succeed: t1: D0(t0), D1(t0), D2(t0), D3(t0) t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0) t3: d5(t1), D1(t0), D2(t0), D3(t0) ... t9: d9(t7), D3(t0) t10: D3(t0) t11: d10(t10), d11(t10) t12: d11(t10) In transaction 9, we finish d9 and try to roll to t10 while holding onto an intent item for D3 that we logged in t0. The previous commit changed the order in which we place new defer ops in the defer ops processing chain to reduce the maximum chain length. Now make xfs_defer_finish_noroll capable of relogging the entire chain periodically so that we can always move the log tail forward. Most chains will never get relogged, except for operations that generate very long chains (large extents containing many blocks with different sharing levels) or are on filesystems with small logs and a lot of ongoing metadata updates. Callers are now required to ensure that the transaction reservation is large enough to handle logging done items and new intent items for the maximum possible chain length. Most callers are careful to keep the chain lengths low, so the overhead should be minimal. The decision to relog an intent item is made based on whether the intent was logged in a previous checkpoint, since there's no point in relogging an intent into the same checkpoint. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-28 07:18:13 +08:00
{
struct xfs_bui_log_item *buip;
struct xfs_map_extent *map;
xfs: periodically relog deferred intent items There's a subtle design flaw in the deferred log item code that can lead to pinning the log tail. Taking up the defer ops chain examples from the previous commit, we can get trapped in sequences like this: Caller hands us a transaction t0 with D0-D3 attached. The defer ops chain will look like the following if the transaction rolls succeed: t1: D0(t0), D1(t0), D2(t0), D3(t0) t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0) t3: d5(t1), D1(t0), D2(t0), D3(t0) ... t9: d9(t7), D3(t0) t10: D3(t0) t11: d10(t10), d11(t10) t12: d11(t10) In transaction 9, we finish d9 and try to roll to t10 while holding onto an intent item for D3 that we logged in t0. The previous commit changed the order in which we place new defer ops in the defer ops processing chain to reduce the maximum chain length. Now make xfs_defer_finish_noroll capable of relogging the entire chain periodically so that we can always move the log tail forward. Most chains will never get relogged, except for operations that generate very long chains (large extents containing many blocks with different sharing levels) or are on filesystems with small logs and a lot of ongoing metadata updates. Callers are now required to ensure that the transaction reservation is large enough to handle logging done items and new intent items for the maximum possible chain length. Most callers are careful to keep the chain lengths low, so the overhead should be minimal. The decision to relog an intent item is made based on whether the intent was logged in a previous checkpoint, since there's no point in relogging an intent into the same checkpoint. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-28 07:18:13 +08:00
unsigned int count;
count = BUI_ITEM(intent)->bui_format.bui_nextents;
map = BUI_ITEM(intent)->bui_format.bui_extents;
xfs: periodically relog deferred intent items There's a subtle design flaw in the deferred log item code that can lead to pinning the log tail. Taking up the defer ops chain examples from the previous commit, we can get trapped in sequences like this: Caller hands us a transaction t0 with D0-D3 attached. The defer ops chain will look like the following if the transaction rolls succeed: t1: D0(t0), D1(t0), D2(t0), D3(t0) t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0) t3: d5(t1), D1(t0), D2(t0), D3(t0) ... t9: d9(t7), D3(t0) t10: D3(t0) t11: d10(t10), d11(t10) t12: d11(t10) In transaction 9, we finish d9 and try to roll to t10 while holding onto an intent item for D3 that we logged in t0. The previous commit changed the order in which we place new defer ops in the defer ops processing chain to reduce the maximum chain length. Now make xfs_defer_finish_noroll capable of relogging the entire chain periodically so that we can always move the log tail forward. Most chains will never get relogged, except for operations that generate very long chains (large extents containing many blocks with different sharing levels) or are on filesystems with small logs and a lot of ongoing metadata updates. Callers are now required to ensure that the transaction reservation is large enough to handle logging done items and new intent items for the maximum possible chain length. Most callers are careful to keep the chain lengths low, so the overhead should be minimal. The decision to relog an intent item is made based on whether the intent was logged in a previous checkpoint, since there's no point in relogging an intent into the same checkpoint. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-28 07:18:13 +08:00
buip = xfs_bui_init(tp->t_mountp);
memcpy(buip->bui_format.bui_extents, map, count * sizeof(*map));
xfs: periodically relog deferred intent items There's a subtle design flaw in the deferred log item code that can lead to pinning the log tail. Taking up the defer ops chain examples from the previous commit, we can get trapped in sequences like this: Caller hands us a transaction t0 with D0-D3 attached. The defer ops chain will look like the following if the transaction rolls succeed: t1: D0(t0), D1(t0), D2(t0), D3(t0) t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0) t3: d5(t1), D1(t0), D2(t0), D3(t0) ... t9: d9(t7), D3(t0) t10: D3(t0) t11: d10(t10), d11(t10) t12: d11(t10) In transaction 9, we finish d9 and try to roll to t10 while holding onto an intent item for D3 that we logged in t0. The previous commit changed the order in which we place new defer ops in the defer ops processing chain to reduce the maximum chain length. Now make xfs_defer_finish_noroll capable of relogging the entire chain periodically so that we can always move the log tail forward. Most chains will never get relogged, except for operations that generate very long chains (large extents containing many blocks with different sharing levels) or are on filesystems with small logs and a lot of ongoing metadata updates. Callers are now required to ensure that the transaction reservation is large enough to handle logging done items and new intent items for the maximum possible chain length. Most callers are careful to keep the chain lengths low, so the overhead should be minimal. The decision to relog an intent item is made based on whether the intent was logged in a previous checkpoint, since there's no point in relogging an intent into the same checkpoint. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-28 07:18:13 +08:00
atomic_set(&buip->bui_next_extent, count);
xfs: periodically relog deferred intent items There's a subtle design flaw in the deferred log item code that can lead to pinning the log tail. Taking up the defer ops chain examples from the previous commit, we can get trapped in sequences like this: Caller hands us a transaction t0 with D0-D3 attached. The defer ops chain will look like the following if the transaction rolls succeed: t1: D0(t0), D1(t0), D2(t0), D3(t0) t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0) t3: d5(t1), D1(t0), D2(t0), D3(t0) ... t9: d9(t7), D3(t0) t10: D3(t0) t11: d10(t10), d11(t10) t12: d11(t10) In transaction 9, we finish d9 and try to roll to t10 while holding onto an intent item for D3 that we logged in t0. The previous commit changed the order in which we place new defer ops in the defer ops processing chain to reduce the maximum chain length. Now make xfs_defer_finish_noroll capable of relogging the entire chain periodically so that we can always move the log tail forward. Most chains will never get relogged, except for operations that generate very long chains (large extents containing many blocks with different sharing levels) or are on filesystems with small logs and a lot of ongoing metadata updates. Callers are now required to ensure that the transaction reservation is large enough to handle logging done items and new intent items for the maximum possible chain length. Most callers are careful to keep the chain lengths low, so the overhead should be minimal. The decision to relog an intent item is made based on whether the intent was logged in a previous checkpoint, since there's no point in relogging an intent into the same checkpoint. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-28 07:18:13 +08:00
return &buip->bui_item;
}
const struct xfs_defer_op_type xfs_bmap_update_defer_type = {
.name = "bmap",
.max_items = XFS_BUI_MAX_FAST_EXTENTS,
.create_intent = xfs_bmap_update_create_intent,
.abort_intent = xfs_bmap_update_abort_intent,
.create_done = xfs_bmap_update_create_done,
.finish_item = xfs_bmap_update_finish_item,
.cancel_item = xfs_bmap_update_cancel_item,
.recover_work = xfs_bmap_recover_work,
.relog_intent = xfs_bmap_relog_intent,
};
STATIC bool
xfs_bui_item_match(
struct xfs_log_item *lip,
uint64_t intent_id)
{
return BUI_ITEM(lip)->bui_format.bui_id == intent_id;
}
static const struct xfs_item_ops xfs_bui_item_ops = {
.flags = XFS_ITEM_INTENT,
.iop_size = xfs_bui_item_size,
.iop_format = xfs_bui_item_format,
.iop_unpin = xfs_bui_item_unpin,
.iop_release = xfs_bui_item_release,
.iop_match = xfs_bui_item_match,
};
static inline void
xfs_bui_copy_format(
struct xfs_bui_log_format *dst,
const struct xfs_bui_log_format *src)
{
unsigned int i;
memcpy(dst, src, offsetof(struct xfs_bui_log_format, bui_extents));
for (i = 0; i < src->bui_nextents; i++)
memcpy(&dst->bui_extents[i], &src->bui_extents[i],
sizeof(struct xfs_map_extent));
}
/*
* This routine is called to create an in-core extent bmap update
* item from the bui format structure which was logged on disk.
* It allocates an in-core bui, copies the extents from the format
* structure into it, and adds the bui to the AIL with the given
* LSN.
*/
STATIC int
xlog_recover_bui_commit_pass2(
struct xlog *log,
struct list_head *buffer_list,
struct xlog_recover_item *item,
xfs_lsn_t lsn)
{
struct xfs_mount *mp = log->l_mp;
struct xfs_bui_log_item *buip;
struct xfs_bui_log_format *bui_formatp;
size_t len;
bui_formatp = item->ri_buf[0].i_addr;
if (item->ri_buf[0].i_len < xfs_bui_log_format_sizeof(0)) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
item->ri_buf[0].i_addr, item->ri_buf[0].i_len);
return -EFSCORRUPTED;
}
if (bui_formatp->bui_nextents != XFS_BUI_MAX_FAST_EXTENTS) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
item->ri_buf[0].i_addr, item->ri_buf[0].i_len);
return -EFSCORRUPTED;
}
len = xfs_bui_log_format_sizeof(bui_formatp->bui_nextents);
if (item->ri_buf[0].i_len != len) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
item->ri_buf[0].i_addr, item->ri_buf[0].i_len);
return -EFSCORRUPTED;
}
buip = xfs_bui_init(mp);
xfs_bui_copy_format(&buip->bui_format, bui_formatp);
atomic_set(&buip->bui_next_extent, bui_formatp->bui_nextents);
xfs: use xfs_defer_pending objects to recover intent items One thing I never quite got around to doing is porting the log intent item recovery code to reconstruct the deferred pending work state. As a result, each intent item open codes xfs_defer_finish_one in its recovery method, because that's what the EFI code did before xfs_defer.c even existed. This is a gross thing to have left unfixed -- if an EFI cannot proceed due to busy extents, we end up creating separate new EFIs for each unfinished work item, which is a change in behavior from what runtime would have done. Worse yet, Long Li pointed out that there's a UAF in the recovery code. The ->commit_pass2 function adds the intent item to the AIL and drops the refcount. The one remaining refcount is now owned by the recovery mechanism (aka the log intent items in the AIL) with the intent of giving the refcount to the intent done item in the ->iop_recover function. However, if something fails later in recovery, xlog_recover_finish will walk the recovered intent items in the AIL and release them. If the CIL hasn't been pushed before that point (which is possible since we don't force the log until later) then the intent done release will try to free its associated intent, which has already been freed. This patch starts to address this mess by having the ->commit_pass2 functions recreate the xfs_defer_pending state. The next few patches will fix the recovery functions. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-11-23 02:23:23 +08:00
xlog_recover_intent_item(log, &buip->bui_item, lsn,
&xfs_bmap_update_defer_type);
return 0;
}
const struct xlog_recover_item_ops xlog_bui_item_ops = {
.item_type = XFS_LI_BUI,
.commit_pass2 = xlog_recover_bui_commit_pass2,
};
/*
* This routine is called when an BUD format structure is found in a committed
* transaction in the log. Its purpose is to cancel the corresponding BUI if it
* was still in the log. To do this it searches the AIL for the BUI with an id
* equal to that in the BUD format structure. If we find it we drop the BUD
* reference, which removes the BUI from the AIL and frees it.
*/
STATIC int
xlog_recover_bud_commit_pass2(
struct xlog *log,
struct list_head *buffer_list,
struct xlog_recover_item *item,
xfs_lsn_t lsn)
{
struct xfs_bud_log_format *bud_formatp;
bud_formatp = item->ri_buf[0].i_addr;
if (item->ri_buf[0].i_len != sizeof(struct xfs_bud_log_format)) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, log->l_mp,
item->ri_buf[0].i_addr, item->ri_buf[0].i_len);
return -EFSCORRUPTED;
}
xlog_recover_release_intent(log, XFS_LI_BUI, bud_formatp->bud_bui_id);
return 0;
}
const struct xlog_recover_item_ops xlog_bud_item_ops = {
.item_type = XFS_LI_BUD,
.commit_pass2 = xlog_recover_bud_commit_pass2,
};