linux/fs/xfs/libxfs/xfs_ag.h
Dave Chinner 2fd26cc07e xfs: double link the unlinked inode list
Now we have forwards traversal via the incore inode in place, we now
need to add back pointers to the incore inode to entirely replace
the back reference cache. We use the same lookup semantics and
constraints as for the forwards pointer lookups during unlinks, and
so we can look up any inode in the unlinked list directly and update
the list pointers, forwards or backwards, at any time.

The only wrinkle in converting the unlinked list manipulations to
use in-core previous pointers is that log recovery doesn't have the
incore inode state built up so it can't just read in an inode and
release it to finish off the unlink. Hence we need to modify the
traversal in recovery to read one inode ahead before we
release the inode at the head of the list. This populates the
next->prev relationship sufficient to be able to replay the unlinked
list and hence greatly simplify the runtime code.

This recovery algorithm also requires that we actually remove inodes
from the unlinked list one at a time as background inode
inactivation will result in unlinked list removal racing with the
building of the in-memory unlinked list state. We could serialise
this by holding the AGI buffer lock when constructing the in memory
state, but all that does is lockstep background processing with list
building. It is much simpler to flush the inodegc immediately after
releasing the inode so that it is unlinked immediately and there is
no races present at all.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2022-07-14 11:46:43 +10:00

228 lines
6.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2018 Red Hat, Inc.
* All rights reserved.
*/
#ifndef __LIBXFS_AG_H
#define __LIBXFS_AG_H 1
struct xfs_mount;
struct xfs_trans;
struct xfs_perag;
/*
* Per-ag infrastructure
*/
/* per-AG block reservation data structures*/
struct xfs_ag_resv {
/* number of blocks originally reserved here */
xfs_extlen_t ar_orig_reserved;
/* number of blocks reserved here */
xfs_extlen_t ar_reserved;
/* number of blocks originally asked for */
xfs_extlen_t ar_asked;
};
/*
* Per-ag incore structure, copies of information in agf and agi, to improve the
* performance of allocation group selection.
*/
struct xfs_perag {
struct xfs_mount *pag_mount; /* owner filesystem */
xfs_agnumber_t pag_agno; /* AG this structure belongs to */
atomic_t pag_ref; /* perag reference count */
char pagf_init; /* this agf's entry is initialized */
char pagi_init; /* this agi's entry is initialized */
char pagf_metadata; /* the agf is preferred to be metadata */
char pagi_inodeok; /* The agi is ok for inodes */
uint8_t pagf_levels[XFS_BTNUM_AGF];
/* # of levels in bno & cnt btree */
bool pagf_agflreset; /* agfl requires reset before use */
uint32_t pagf_flcount; /* count of blocks in freelist */
xfs_extlen_t pagf_freeblks; /* total free blocks */
xfs_extlen_t pagf_longest; /* longest free space */
uint32_t pagf_btreeblks; /* # of blocks held in AGF btrees */
xfs_agino_t pagi_freecount; /* number of free inodes */
xfs_agino_t pagi_count; /* number of allocated inodes */
/*
* Inode allocation search lookup optimisation.
* If the pagino matches, the search for new inodes
* doesn't need to search the near ones again straight away
*/
xfs_agino_t pagl_pagino;
xfs_agino_t pagl_leftrec;
xfs_agino_t pagl_rightrec;
int pagb_count; /* pagb slots in use */
uint8_t pagf_refcount_level; /* recount btree height */
/* Blocks reserved for all kinds of metadata. */
struct xfs_ag_resv pag_meta_resv;
/* Blocks reserved for the reverse mapping btree. */
struct xfs_ag_resv pag_rmapbt_resv;
/* for rcu-safe freeing */
struct rcu_head rcu_head;
/* Precalculated geometry info */
xfs_agblock_t block_count;
xfs_agblock_t min_block;
xfs_agino_t agino_min;
xfs_agino_t agino_max;
#ifdef __KERNEL__
/* -- kernel only structures below this line -- */
/*
* Bitsets of per-ag metadata that have been checked and/or are sick.
* Callers should hold pag_state_lock before accessing this field.
*/
uint16_t pag_checked;
uint16_t pag_sick;
spinlock_t pag_state_lock;
spinlock_t pagb_lock; /* lock for pagb_tree */
struct rb_root pagb_tree; /* ordered tree of busy extents */
unsigned int pagb_gen; /* generation count for pagb_tree */
wait_queue_head_t pagb_wait; /* woken when pagb_gen changes */
atomic_t pagf_fstrms; /* # of filestreams active in this AG */
spinlock_t pag_ici_lock; /* incore inode cache lock */
struct radix_tree_root pag_ici_root; /* incore inode cache root */
int pag_ici_reclaimable; /* reclaimable inodes */
unsigned long pag_ici_reclaim_cursor; /* reclaim restart point */
/* buffer cache index */
spinlock_t pag_buf_lock; /* lock for pag_buf_hash */
struct rhashtable pag_buf_hash;
/* background prealloc block trimming */
struct delayed_work pag_blockgc_work;
#endif /* __KERNEL__ */
};
int xfs_initialize_perag(struct xfs_mount *mp, xfs_agnumber_t agcount,
xfs_rfsblock_t dcount, xfs_agnumber_t *maxagi);
int xfs_initialize_perag_data(struct xfs_mount *mp, xfs_agnumber_t agno);
void xfs_free_perag(struct xfs_mount *mp);
struct xfs_perag *xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno);
struct xfs_perag *xfs_perag_get_tag(struct xfs_mount *mp, xfs_agnumber_t agno,
unsigned int tag);
void xfs_perag_put(struct xfs_perag *pag);
/*
* Per-ag geometry infomation and validation
*/
xfs_agblock_t xfs_ag_block_count(struct xfs_mount *mp, xfs_agnumber_t agno);
void xfs_agino_range(struct xfs_mount *mp, xfs_agnumber_t agno,
xfs_agino_t *first, xfs_agino_t *last);
static inline bool
xfs_verify_agbno(struct xfs_perag *pag, xfs_agblock_t agbno)
{
if (agbno >= pag->block_count)
return false;
if (agbno <= pag->min_block)
return false;
return true;
}
/*
* Verify that an AG inode number pointer neither points outside the AG
* nor points at static metadata.
*/
static inline bool
xfs_verify_agino(struct xfs_perag *pag, xfs_agino_t agino)
{
if (agino < pag->agino_min)
return false;
if (agino > pag->agino_max)
return false;
return true;
}
/*
* Verify that an AG inode number pointer neither points outside the AG
* nor points at static metadata, or is NULLAGINO.
*/
static inline bool
xfs_verify_agino_or_null(struct xfs_perag *pag, xfs_agino_t agino)
{
if (agino == NULLAGINO)
return true;
return xfs_verify_agino(pag, agino);
}
static inline bool
xfs_ag_contains_log(struct xfs_mount *mp, xfs_agnumber_t agno)
{
return mp->m_sb.sb_logstart > 0 &&
agno == XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart);
}
/*
* Perag iteration APIs
*/
static inline struct xfs_perag *
xfs_perag_next(
struct xfs_perag *pag,
xfs_agnumber_t *agno,
xfs_agnumber_t end_agno)
{
struct xfs_mount *mp = pag->pag_mount;
*agno = pag->pag_agno + 1;
xfs_perag_put(pag);
if (*agno > end_agno)
return NULL;
return xfs_perag_get(mp, *agno);
}
#define for_each_perag_range(mp, agno, end_agno, pag) \
for ((pag) = xfs_perag_get((mp), (agno)); \
(pag) != NULL; \
(pag) = xfs_perag_next((pag), &(agno), (end_agno)))
#define for_each_perag_from(mp, agno, pag) \
for_each_perag_range((mp), (agno), (mp)->m_sb.sb_agcount - 1, (pag))
#define for_each_perag(mp, agno, pag) \
(agno) = 0; \
for_each_perag_from((mp), (agno), (pag))
#define for_each_perag_tag(mp, agno, pag, tag) \
for ((agno) = 0, (pag) = xfs_perag_get_tag((mp), 0, (tag)); \
(pag) != NULL; \
(agno) = (pag)->pag_agno + 1, \
xfs_perag_put(pag), \
(pag) = xfs_perag_get_tag((mp), (agno), (tag)))
struct aghdr_init_data {
/* per ag data */
xfs_agblock_t agno; /* ag to init */
xfs_extlen_t agsize; /* new AG size */
struct list_head buffer_list; /* buffer writeback list */
xfs_rfsblock_t nfree; /* cumulative new free space */
/* per header data */
xfs_daddr_t daddr; /* header location */
size_t numblks; /* size of header */
xfs_btnum_t type; /* type of btree root block */
};
int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id);
int xfs_ag_shrink_space(struct xfs_perag *pag, struct xfs_trans **tpp,
xfs_extlen_t delta);
int xfs_ag_extend_space(struct xfs_perag *pag, struct xfs_trans *tp,
xfs_extlen_t len);
int xfs_ag_get_geometry(struct xfs_perag *pag, struct xfs_ag_geometry *ageo);
#endif /* __LIBXFS_AG_H */