linux-stable/fs/xfs/libxfs/xfs_defer.h

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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>
*/
#ifndef __XFS_DEFER_H__
#define __XFS_DEFER_H__
struct xfs_btree_cur;
struct xfs_defer_op_type;
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 00:39:37 +00:00
struct xfs_defer_capture;
/*
* Save a log intent item and a list of extents, so that we can replay
* whatever action had to happen to the extent list and file the log done
* item.
*/
struct xfs_defer_pending {
struct list_head dfp_list; /* pending items */
struct list_head dfp_work; /* work items */
struct xfs_log_item *dfp_intent; /* log intent item */
struct xfs_log_item *dfp_done; /* log done item */
const struct xfs_defer_op_type *dfp_ops;
unsigned int dfp_count; /* # extent items */
unsigned int dfp_flags;
};
/*
* Create a log intent item for this deferred item, but don't actually finish
* the work. Caller must clear this before the final transaction commit.
*/
#define XFS_DEFER_PAUSED (1U << 0)
#define XFS_DEFER_PENDING_STRINGS \
{ XFS_DEFER_PAUSED, "paused" }
void xfs_defer_item_pause(struct xfs_trans *tp, struct xfs_defer_pending *dfp);
void xfs_defer_item_unpause(struct xfs_trans *tp, struct xfs_defer_pending *dfp);
struct xfs_defer_pending *xfs_defer_add(struct xfs_trans *tp, struct list_head *h,
const struct xfs_defer_op_type *ops);
int xfs_defer_finish_noroll(struct xfs_trans **tp);
int xfs_defer_finish(struct xfs_trans **tp);
int xfs_defer_finish_one(struct xfs_trans *tp, struct xfs_defer_pending *dfp);
void xfs_defer_cancel(struct xfs_trans *);
void xfs_defer_move(struct xfs_trans *dtp, struct xfs_trans *stp);
/* Description of a deferred type. */
struct xfs_defer_op_type {
const char *name;
unsigned int max_items;
struct xfs_log_item *(*create_intent)(struct xfs_trans *tp,
struct list_head *items, unsigned int count, bool sort);
void (*abort_intent)(struct xfs_log_item *intent);
struct xfs_log_item *(*create_done)(struct xfs_trans *tp,
struct xfs_log_item *intent, unsigned int count);
int (*finish_item)(struct xfs_trans *tp, struct xfs_log_item *done,
struct list_head *item, struct xfs_btree_cur **state);
void (*finish_cleanup)(struct xfs_trans *tp,
struct xfs_btree_cur *state, int error);
void (*cancel_item)(struct list_head *item);
int (*recover_work)(struct xfs_defer_pending *dfp,
struct list_head *capture_list);
struct xfs_log_item *(*relog_intent)(struct xfs_trans *tp,
struct xfs_log_item *intent,
struct xfs_log_item *done_item);
};
extern const struct xfs_defer_op_type xfs_bmap_update_defer_type;
extern const struct xfs_defer_op_type xfs_refcount_update_defer_type;
extern const struct xfs_defer_op_type xfs_rmap_update_defer_type;
extern const struct xfs_defer_op_type xfs_extent_free_defer_type;
extern const struct xfs_defer_op_type xfs_agfl_free_defer_type;
xfs: Set up infrastructure for log attribute replay Currently attributes are modified directly across one or more transactions. But they are not logged or replayed in the event of an error. The goal of log attr replay is to enable logging and replaying of attribute operations using the existing delayed operations infrastructure. This will later enable the attributes to become part of larger multi part operations that also must first be recorded to the log. This is mostly of interest in the scheme of parent pointers which would need to maintain an attribute containing parent inode information any time an inode is moved, created, or removed. Parent pointers would then be of interest to any feature that would need to quickly derive an inode path from the mount point. Online scrub, nfs lookups and fs grow or shrink operations are all features that could take advantage of this. This patch adds two new log item types for setting or removing attributes as deferred operations. The xfs_attri_log_item will log an intent to set or remove an attribute. The corresponding xfs_attrd_log_item holds a reference to the xfs_attri_log_item and is freed once the transaction is done. Both log items use a generic xfs_attr_log_format structure that contains the attribute name, value, flags, inode, and an op_flag that indicates if the operations is a set or remove. [dchinner: added extra little bits needed for intent whiteouts] Signed-off-by: Allison Henderson <allison.henderson@oracle.com> Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Dave Chinner <david@fromorbit.com>
2022-05-04 02:41:02 +00:00
extern const struct xfs_defer_op_type xfs_attr_defer_type;
/*
* Deferred operation item relogging limits.
*/
#define XFS_DEFER_OPS_NR_INODES 2 /* join up to two inodes */
#define XFS_DEFER_OPS_NR_BUFS 2 /* join up to two buffers */
/* Resources that must be held across a transaction roll. */
struct xfs_defer_resources {
/* held buffers */
struct xfs_buf *dr_bp[XFS_DEFER_OPS_NR_BUFS];
/* inodes with no unlock flags */
struct xfs_inode *dr_ip[XFS_DEFER_OPS_NR_INODES];
/* number of held buffers */
unsigned short dr_bufs;
/* bitmap of ordered buffers */
unsigned short dr_ordered;
/* number of held inodes */
unsigned short dr_inos;
};
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 00:39:37 +00:00
/*
* This structure enables a dfops user to detach the chain of deferred
* operations from a transaction so that they can be continued later.
*/
struct xfs_defer_capture {
/* List of other capture structures. */
struct list_head dfc_list;
/* Deferred ops state saved from the transaction. */
struct list_head dfc_dfops;
unsigned int dfc_tpflags;
/* Block reservations for the data and rt devices. */
unsigned int dfc_blkres;
unsigned int dfc_rtxres;
/* Log reservation saved from the transaction. */
unsigned int dfc_logres;
struct xfs_defer_resources dfc_held;
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 00:39:37 +00:00
};
/*
* Functions to capture a chain of deferred operations and continue them later.
* This doesn't normally happen except log recovery.
*/
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 00:39:37 +00:00
int xfs_defer_ops_capture_and_commit(struct xfs_trans *tp,
struct list_head *capture_list);
void xfs_defer_ops_continue(struct xfs_defer_capture *d, struct xfs_trans *tp,
struct xfs_defer_resources *dres);
xfs: abort intent items when recovery intents fail When recovering intents, we capture newly created intent items as part of committing recovered intent items. If intent recovery fails at a later point, we forget to remove those newly created intent items from the AIL and hang: [root@localhost ~]# cat /proc/539/stack [<0>] xfs_ail_push_all_sync+0x174/0x230 [<0>] xfs_unmount_flush_inodes+0x8d/0xd0 [<0>] xfs_mountfs+0x15f7/0x1e70 [<0>] xfs_fs_fill_super+0x10ec/0x1b20 [<0>] get_tree_bdev+0x3c8/0x730 [<0>] vfs_get_tree+0x89/0x2c0 [<0>] path_mount+0xecf/0x1800 [<0>] do_mount+0xf3/0x110 [<0>] __x64_sys_mount+0x154/0x1f0 [<0>] do_syscall_64+0x39/0x80 [<0>] entry_SYSCALL_64_after_hwframe+0x63/0xcd When newly created intent items fail to commit via transaction, intent recovery hasn't created done items for these newly created intent items, so the capture structure is the sole owner of the captured intent items. We must release them explicitly or else they leak: unreferenced object 0xffff888016719108 (size 432): comm "mount", pid 529, jiffies 4294706839 (age 144.463s) hex dump (first 32 bytes): 08 91 71 16 80 88 ff ff 08 91 71 16 80 88 ff ff ..q.......q..... 18 91 71 16 80 88 ff ff 18 91 71 16 80 88 ff ff ..q.......q..... backtrace: [<ffffffff8230c68f>] xfs_efi_init+0x18f/0x1d0 [<ffffffff8230c720>] xfs_extent_free_create_intent+0x50/0x150 [<ffffffff821b671a>] xfs_defer_create_intents+0x16a/0x340 [<ffffffff821bac3e>] xfs_defer_ops_capture_and_commit+0x8e/0xad0 [<ffffffff82322bb9>] xfs_cui_item_recover+0x819/0x980 [<ffffffff823289b6>] xlog_recover_process_intents+0x246/0xb70 [<ffffffff8233249a>] xlog_recover_finish+0x8a/0x9a0 [<ffffffff822eeafb>] xfs_log_mount_finish+0x2bb/0x4a0 [<ffffffff822c0f4f>] xfs_mountfs+0x14bf/0x1e70 [<ffffffff822d1f80>] xfs_fs_fill_super+0x10d0/0x1b20 [<ffffffff81a21fa2>] get_tree_bdev+0x3d2/0x6d0 [<ffffffff81a1ee09>] vfs_get_tree+0x89/0x2c0 [<ffffffff81a9f35f>] path_mount+0xecf/0x1800 [<ffffffff81a9fd83>] do_mount+0xf3/0x110 [<ffffffff81aa00e4>] __x64_sys_mount+0x154/0x1f0 [<ffffffff83968739>] do_syscall_64+0x39/0x80 Fix the problem above by abort intent items that don't have a done item when recovery intents fail. Fixes: e6fff81e4870 ("xfs: proper replay of deferred ops queued during log recovery") Signed-off-by: Long Li <leo.lilong@huawei.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2023-07-31 12:46:18 +00:00
void xfs_defer_ops_capture_abort(struct xfs_mount *mp,
struct xfs_defer_capture *d);
void xfs_defer_resources_rele(struct xfs_defer_resources *dres);
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>
2023-11-22 18:23:23 +00:00
void xfs_defer_start_recovery(struct xfs_log_item *lip,
struct list_head *r_dfops, const struct xfs_defer_op_type *ops);
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>
2023-11-22 18:23:23 +00:00
void xfs_defer_cancel_recovery(struct xfs_mount *mp,
struct xfs_defer_pending *dfp);
int xfs_defer_finish_recovery(struct xfs_mount *mp,
struct xfs_defer_pending *dfp, struct list_head *capture_list);
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>
2023-11-22 18:23:23 +00:00
static inline void
xfs_defer_add_item(
struct xfs_defer_pending *dfp,
struct list_head *work)
{
list_add_tail(work, &dfp->dfp_work);
dfp->dfp_count++;
}
int __init xfs_defer_init_item_caches(void);
void xfs_defer_destroy_item_caches(void);
void xfs_defer_add_barrier(struct xfs_trans *tp);
#endif /* __XFS_DEFER_H__ */