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f492135df0
Create a helper function to ensure that CoW staging extent records have a single refcount and that shared extent records have more than 1 refcount. We'll put this to more use in the next patch. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
127 lines
4.3 KiB
C
127 lines
4.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2016 Oracle. All Rights Reserved.
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* Author: Darrick J. Wong <darrick.wong@oracle.com>
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*/
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#ifndef __XFS_REFCOUNT_H__
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#define __XFS_REFCOUNT_H__
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struct xfs_trans;
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struct xfs_mount;
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struct xfs_perag;
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struct xfs_btree_cur;
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struct xfs_bmbt_irec;
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struct xfs_refcount_irec;
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extern int xfs_refcount_lookup_le(struct xfs_btree_cur *cur,
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enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
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extern int xfs_refcount_lookup_ge(struct xfs_btree_cur *cur,
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enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
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extern int xfs_refcount_lookup_eq(struct xfs_btree_cur *cur,
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enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
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extern int xfs_refcount_get_rec(struct xfs_btree_cur *cur,
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struct xfs_refcount_irec *irec, int *stat);
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static inline uint32_t
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xfs_refcount_encode_startblock(
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xfs_agblock_t startblock,
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enum xfs_refc_domain domain)
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{
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uint32_t start;
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/*
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* low level btree operations need to handle the generic btree range
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* query functions (which set rc_domain == -1U), so we check that the
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* domain is /not/ shared.
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*/
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start = startblock & ~XFS_REFC_COW_START;
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if (domain != XFS_REFC_DOMAIN_SHARED)
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start |= XFS_REFC_COW_START;
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return start;
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}
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enum xfs_refcount_intent_type {
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XFS_REFCOUNT_INCREASE = 1,
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XFS_REFCOUNT_DECREASE,
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XFS_REFCOUNT_ALLOC_COW,
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XFS_REFCOUNT_FREE_COW,
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};
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struct xfs_refcount_intent {
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struct list_head ri_list;
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enum xfs_refcount_intent_type ri_type;
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xfs_extlen_t ri_blockcount;
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xfs_fsblock_t ri_startblock;
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};
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/* Check that the refcount is appropriate for the record domain. */
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static inline bool
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xfs_refcount_check_domain(
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const struct xfs_refcount_irec *irec)
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{
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if (irec->rc_domain == XFS_REFC_DOMAIN_COW && irec->rc_refcount != 1)
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return false;
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if (irec->rc_domain == XFS_REFC_DOMAIN_SHARED && irec->rc_refcount < 2)
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return false;
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return true;
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}
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void xfs_refcount_increase_extent(struct xfs_trans *tp,
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struct xfs_bmbt_irec *irec);
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void xfs_refcount_decrease_extent(struct xfs_trans *tp,
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struct xfs_bmbt_irec *irec);
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extern void xfs_refcount_finish_one_cleanup(struct xfs_trans *tp,
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struct xfs_btree_cur *rcur, int error);
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extern int xfs_refcount_finish_one(struct xfs_trans *tp,
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enum xfs_refcount_intent_type type, xfs_fsblock_t startblock,
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xfs_extlen_t blockcount, xfs_fsblock_t *new_fsb,
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xfs_extlen_t *new_len, struct xfs_btree_cur **pcur);
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extern int xfs_refcount_find_shared(struct xfs_btree_cur *cur,
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xfs_agblock_t agbno, xfs_extlen_t aglen, xfs_agblock_t *fbno,
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xfs_extlen_t *flen, bool find_end_of_shared);
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void xfs_refcount_alloc_cow_extent(struct xfs_trans *tp, xfs_fsblock_t fsb,
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xfs_extlen_t len);
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void xfs_refcount_free_cow_extent(struct xfs_trans *tp, xfs_fsblock_t fsb,
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xfs_extlen_t len);
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extern int xfs_refcount_recover_cow_leftovers(struct xfs_mount *mp,
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struct xfs_perag *pag);
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/*
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* While we're adjusting the refcounts records of an extent, we have
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* to keep an eye on the number of extents we're dirtying -- run too
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* many in a single transaction and we'll exceed the transaction's
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* reservation and crash the fs. Each record adds 12 bytes to the
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* log (plus any key updates) so we'll conservatively assume 32 bytes
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* per record. We must also leave space for btree splits on both ends
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* of the range and space for the CUD and a new CUI.
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*
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* Each EFI that we attach to the transaction is assumed to consume ~32 bytes.
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* This is a low estimate for an EFI tracking a single extent (16 bytes for the
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* EFI header, 16 for the extent, and 12 for the xlog op header), but the
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* estimate is acceptable if there's more than one extent being freed.
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* In the worst case of freeing every other block during a refcount decrease
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* operation, we amortize the space used for one EFI log item across 16
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* extents.
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*/
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#define XFS_REFCOUNT_ITEM_OVERHEAD 32
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extern int xfs_refcount_has_record(struct xfs_btree_cur *cur,
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enum xfs_refc_domain domain, xfs_agblock_t bno,
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xfs_extlen_t len, bool *exists);
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union xfs_btree_rec;
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extern void xfs_refcount_btrec_to_irec(const union xfs_btree_rec *rec,
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struct xfs_refcount_irec *irec);
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extern int xfs_refcount_insert(struct xfs_btree_cur *cur,
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struct xfs_refcount_irec *irec, int *stat);
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extern struct kmem_cache *xfs_refcount_intent_cache;
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int __init xfs_refcount_intent_init_cache(void);
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void xfs_refcount_intent_destroy_cache(void);
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#endif /* __XFS_REFCOUNT_H__ */
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