diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile index aceca2f9a3db..4f95df476181 100644 --- a/fs/xfs/Makefile +++ b/fs/xfs/Makefile @@ -26,6 +26,7 @@ xfs-y += $(addprefix libxfs/, \ xfs_bmap.o \ xfs_bmap_btree.o \ xfs_btree.o \ + xfs_btree_staging.o \ xfs_da_btree.o \ xfs_defer.o \ xfs_dir2.o \ diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c index 4ef9f0b42c7f..e81db0f38ba8 100644 --- a/fs/xfs/libxfs/xfs_btree.c +++ b/fs/xfs/libxfs/xfs_btree.c @@ -20,6 +20,7 @@ #include "xfs_trace.h" #include "xfs_alloc.h" #include "xfs_log.h" +#include "xfs_btree_staging.h" /* * Cursor allocation zone. @@ -382,6 +383,8 @@ xfs_btree_del_cursor( /* * Free the cursor. */ + if (unlikely(cur->bc_flags & XFS_BTREE_STAGING)) + kmem_free((void *)cur->bc_ops); kmem_cache_free(xfs_btree_cur_zone, cur); } diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h index 133b858bf096..d6e201ff4027 100644 --- a/fs/xfs/libxfs/xfs_btree.h +++ b/fs/xfs/libxfs/xfs_btree.h @@ -179,7 +179,10 @@ union xfs_btree_irec { /* Per-AG btree information. */ struct xfs_btree_cur_ag { - struct xfs_buf *agbp; + union { + struct xfs_buf *agbp; + struct xbtree_afakeroot *afake; /* for staging cursor */ + }; xfs_agnumber_t agno; union { struct { @@ -238,6 +241,12 @@ typedef struct xfs_btree_cur #define XFS_BTREE_LASTREC_UPDATE (1<<2) /* track last rec externally */ #define XFS_BTREE_CRC_BLOCKS (1<<3) /* uses extended btree blocks */ #define XFS_BTREE_OVERLAPPING (1<<4) /* overlapping intervals */ +/* + * The root of this btree is a fakeroot structure so that we can stage a btree + * rebuild without leaving it accessible via primary metadata. The ops struct + * is dynamically allocated and must be freed when the cursor is deleted. + */ +#define XFS_BTREE_STAGING (1<<5) #define XFS_BTREE_NOERROR 0 diff --git a/fs/xfs/libxfs/xfs_btree_staging.c b/fs/xfs/libxfs/xfs_btree_staging.c new file mode 100644 index 000000000000..995a4681e90a --- /dev/null +++ b/fs/xfs/libxfs/xfs_btree_staging.c @@ -0,0 +1,179 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2020 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" +#include "xfs_bit.h" +#include "xfs_mount.h" +#include "xfs_inode.h" +#include "xfs_trans.h" +#include "xfs_btree.h" +#include "xfs_trace.h" +#include "xfs_btree_staging.h" + +/* + * Staging Cursors and Fake Roots for Btrees + * ========================================= + * + * A staging btree cursor is a special type of btree cursor that callers must + * use to construct a new btree index using the btree bulk loader code. The + * bulk loading code uses the staging btree cursor to abstract the details of + * initializing new btree blocks and filling them with records or key/ptr + * pairs. Regular btree operations (e.g. queries and modifications) are not + * supported with staging cursors, and callers must not invoke them. + * + * Fake root structures contain all the information about a btree that is under + * construction by the bulk loading code. Staging btree cursors point to fake + * root structures instead of the usual AG header or inode structure. + * + * Callers are expected to initialize a fake root structure and pass it into + * the _stage_cursor function for a specific btree type. When bulk loading is + * complete, callers should call the _commit_staged_btree function for that + * specific btree type to commit the new btree into the filesystem. + */ + +/* + * Don't allow staging cursors to be duplicated because they're supposed to be + * kept private to a single thread. + */ +STATIC struct xfs_btree_cur * +xfs_btree_fakeroot_dup_cursor( + struct xfs_btree_cur *cur) +{ + ASSERT(0); + return NULL; +} + +/* + * Don't allow block allocation for a staging cursor, because staging cursors + * do not support regular btree modifications. + * + * Bulk loading uses a separate callback to obtain new blocks from a + * preallocated list, which prevents ENOSPC failures during loading. + */ +STATIC int +xfs_btree_fakeroot_alloc_block( + struct xfs_btree_cur *cur, + union xfs_btree_ptr *start_bno, + union xfs_btree_ptr *new_bno, + int *stat) +{ + ASSERT(0); + return -EFSCORRUPTED; +} + +/* + * Don't allow block freeing for a staging cursor, because staging cursors + * do not support regular btree modifications. + */ +STATIC int +xfs_btree_fakeroot_free_block( + struct xfs_btree_cur *cur, + struct xfs_buf *bp) +{ + ASSERT(0); + return -EFSCORRUPTED; +} + +/* Initialize a pointer to the root block from the fakeroot. */ +STATIC void +xfs_btree_fakeroot_init_ptr_from_cur( + struct xfs_btree_cur *cur, + union xfs_btree_ptr *ptr) +{ + struct xbtree_afakeroot *afake; + + ASSERT(cur->bc_flags & XFS_BTREE_STAGING); + + afake = cur->bc_ag.afake; + ptr->s = cpu_to_be32(afake->af_root); +} + +/* + * Bulk Loading for AG Btrees + * ========================== + * + * For a btree rooted in an AG header, pass a xbtree_afakeroot structure to the + * staging cursor. Callers should initialize this to zero. + * + * The _stage_cursor() function for a specific btree type should call + * xfs_btree_stage_afakeroot to set up the in-memory cursor as a staging + * cursor. The corresponding _commit_staged_btree() function should log the + * new root and call xfs_btree_commit_afakeroot() to transform the staging + * cursor into a regular btree cursor. + */ + +/* Update the btree root information for a per-AG fake root. */ +STATIC void +xfs_btree_afakeroot_set_root( + struct xfs_btree_cur *cur, + union xfs_btree_ptr *ptr, + int inc) +{ + struct xbtree_afakeroot *afake = cur->bc_ag.afake; + + ASSERT(cur->bc_flags & XFS_BTREE_STAGING); + afake->af_root = be32_to_cpu(ptr->s); + afake->af_levels += inc; +} + +/* + * Initialize a AG-rooted btree cursor with the given AG btree fake root. + * The btree cursor's bc_ops will be overridden as needed to make the staging + * functionality work. + */ +void +xfs_btree_stage_afakeroot( + struct xfs_btree_cur *cur, + struct xbtree_afakeroot *afake) +{ + struct xfs_btree_ops *nops; + + ASSERT(!(cur->bc_flags & XFS_BTREE_STAGING)); + ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)); + ASSERT(cur->bc_tp == NULL); + + nops = kmem_alloc(sizeof(struct xfs_btree_ops), KM_NOFS); + memcpy(nops, cur->bc_ops, sizeof(struct xfs_btree_ops)); + nops->alloc_block = xfs_btree_fakeroot_alloc_block; + nops->free_block = xfs_btree_fakeroot_free_block; + nops->init_ptr_from_cur = xfs_btree_fakeroot_init_ptr_from_cur; + nops->set_root = xfs_btree_afakeroot_set_root; + nops->dup_cursor = xfs_btree_fakeroot_dup_cursor; + + cur->bc_ag.afake = afake; + cur->bc_nlevels = afake->af_levels; + cur->bc_ops = nops; + cur->bc_flags |= XFS_BTREE_STAGING; +} + +/* + * Transform an AG-rooted staging btree cursor back into a regular cursor by + * substituting a real btree root for the fake one and restoring normal btree + * cursor ops. The caller must log the btree root change prior to calling + * this. + */ +void +xfs_btree_commit_afakeroot( + struct xfs_btree_cur *cur, + struct xfs_trans *tp, + struct xfs_buf *agbp, + const struct xfs_btree_ops *ops) +{ + ASSERT(cur->bc_flags & XFS_BTREE_STAGING); + ASSERT(cur->bc_tp == NULL); + + trace_xfs_btree_commit_afakeroot(cur); + + kmem_free((void *)cur->bc_ops); + cur->bc_ag.agbp = agbp; + cur->bc_ops = ops; + cur->bc_flags &= ~XFS_BTREE_STAGING; + cur->bc_tp = tp; +} diff --git a/fs/xfs/libxfs/xfs_btree_staging.h b/fs/xfs/libxfs/xfs_btree_staging.h new file mode 100644 index 000000000000..5d78e13d2968 --- /dev/null +++ b/fs/xfs/libxfs/xfs_btree_staging.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2020 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#ifndef __XFS_BTREE_STAGING_H__ +#define __XFS_BTREE_STAGING_H__ + +/* Fake root for an AG-rooted btree. */ +struct xbtree_afakeroot { + /* AG block number of the new btree root. */ + xfs_agblock_t af_root; + + /* Height of the new btree. */ + unsigned int af_levels; + + /* Number of blocks used by the btree. */ + unsigned int af_blocks; +}; + +/* Cursor interactions with with fake roots for AG-rooted btrees. */ +void xfs_btree_stage_afakeroot(struct xfs_btree_cur *cur, + struct xbtree_afakeroot *afake); +void xfs_btree_commit_afakeroot(struct xfs_btree_cur *cur, struct xfs_trans *tp, + struct xfs_buf *agbp, const struct xfs_btree_ops *ops); + +#endif /* __XFS_BTREE_STAGING_H__ */ diff --git a/fs/xfs/xfs_trace.c b/fs/xfs/xfs_trace.c index bc85b89f88ca..e9546a6aac10 100644 --- a/fs/xfs/xfs_trace.c +++ b/fs/xfs/xfs_trace.c @@ -27,6 +27,7 @@ #include "xfs_log_recover.h" #include "xfs_filestream.h" #include "xfs_fsmap.h" +#include "xfs_btree_staging.h" /* * We include this last to have the helpers above available for the trace diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index 059c3098a4a0..d8c229492973 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -3605,6 +3605,34 @@ TRACE_EVENT(xfs_check_new_dalign, __entry->calc_rootino) ) +TRACE_EVENT(xfs_btree_commit_afakeroot, + TP_PROTO(struct xfs_btree_cur *cur), + TP_ARGS(cur), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(xfs_btnum_t, btnum) + __field(xfs_agnumber_t, agno) + __field(xfs_agblock_t, agbno) + __field(unsigned int, levels) + __field(unsigned int, blocks) + ), + TP_fast_assign( + __entry->dev = cur->bc_mp->m_super->s_dev; + __entry->btnum = cur->bc_btnum; + __entry->agno = cur->bc_ag.agno; + __entry->agbno = cur->bc_ag.afake->af_root; + __entry->levels = cur->bc_ag.afake->af_levels; + __entry->blocks = cur->bc_ag.afake->af_blocks; + ), + TP_printk("dev %d:%d btree %s ag %u levels %u blocks %u root %u", + MAJOR(__entry->dev), MINOR(__entry->dev), + __print_symbolic(__entry->btnum, XFS_BTNUM_STRINGS), + __entry->agno, + __entry->levels, + __entry->blocks, + __entry->agbno) +) + #endif /* _TRACE_XFS_H */ #undef TRACE_INCLUDE_PATH