From a211432c27ffa32d9978f6c18f5af0c3f8ad2ad1 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 2 Jul 2019 09:39:38 -0700 Subject: xfs: create simplified inode walk function Create a new iterator function to simplify walking inodes in an XFS filesystem. This new iterator will replace the existing open-coded walking that goes on in various places. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster --- fs/xfs/Makefile | 1 + fs/xfs/libxfs/xfs_ialloc_btree.c | 37 +++- fs/xfs/libxfs/xfs_ialloc_btree.h | 3 + fs/xfs/xfs_itable.c | 5 +- fs/xfs/xfs_itable.h | 8 + fs/xfs/xfs_iwalk.c | 389 +++++++++++++++++++++++++++++++++++++++ fs/xfs/xfs_iwalk.h | 19 ++ fs/xfs/xfs_trace.h | 40 ++++ 8 files changed, 496 insertions(+), 6 deletions(-) create mode 100644 fs/xfs/xfs_iwalk.c create mode 100644 fs/xfs/xfs_iwalk.h diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile index 7a87e8411d06..e4dc99dcf5ee 100644 --- a/fs/xfs/Makefile +++ b/fs/xfs/Makefile @@ -81,6 +81,7 @@ xfs-y += xfs_aops.o \ xfs_iops.o \ xfs_inode.o \ xfs_itable.o \ + xfs_iwalk.o \ xfs_message.o \ xfs_mount.o \ xfs_mru_cache.o \ diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c index 3f2772e51d18..b82992f795aa 100644 --- a/fs/xfs/libxfs/xfs_ialloc_btree.c +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c @@ -562,6 +562,36 @@ xfs_inobt_max_size( XFS_INODES_PER_CHUNK); } +/* Read AGI and create inobt cursor. */ +int +xfs_inobt_cur( + struct xfs_mount *mp, + struct xfs_trans *tp, + xfs_agnumber_t agno, + xfs_btnum_t which, + struct xfs_btree_cur **curpp, + struct xfs_buf **agi_bpp) +{ + struct xfs_btree_cur *cur; + int error; + + ASSERT(*agi_bpp == NULL); + ASSERT(*curpp == NULL); + + error = xfs_ialloc_read_agi(mp, tp, agno, agi_bpp); + if (error) + return error; + + cur = xfs_inobt_init_cursor(mp, tp, *agi_bpp, agno, which); + if (!cur) { + xfs_trans_brelse(tp, *agi_bpp); + *agi_bpp = NULL; + return -ENOMEM; + } + *curpp = cur; + return 0; +} + static int xfs_inobt_count_blocks( struct xfs_mount *mp, @@ -570,15 +600,14 @@ xfs_inobt_count_blocks( xfs_btnum_t btnum, xfs_extlen_t *tree_blocks) { - struct xfs_buf *agbp; - struct xfs_btree_cur *cur; + struct xfs_buf *agbp = NULL; + struct xfs_btree_cur *cur = NULL; int error; - error = xfs_ialloc_read_agi(mp, tp, agno, &agbp); + error = xfs_inobt_cur(mp, tp, agno, btnum, &cur, &agbp); if (error) return error; - cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, btnum); error = xfs_btree_count_blocks(cur, tree_blocks); xfs_btree_del_cursor(cur, error); xfs_trans_brelse(tp, agbp); diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.h b/fs/xfs/libxfs/xfs_ialloc_btree.h index ebdd0c6b8766..951305ecaae1 100644 --- a/fs/xfs/libxfs/xfs_ialloc_btree.h +++ b/fs/xfs/libxfs/xfs_ialloc_btree.h @@ -64,5 +64,8 @@ int xfs_finobt_calc_reserves(struct xfs_mount *mp, struct xfs_trans *tp, xfs_agnumber_t agno, xfs_extlen_t *ask, xfs_extlen_t *used); extern xfs_extlen_t xfs_iallocbt_calc_size(struct xfs_mount *mp, unsigned long long len); +int xfs_inobt_cur(struct xfs_mount *mp, struct xfs_trans *tp, + xfs_agnumber_t agno, xfs_btnum_t btnum, + struct xfs_btree_cur **curpp, struct xfs_buf **agi_bpp); #endif /* __XFS_IALLOC_BTREE_H__ */ diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c index 31f5df636d8a..72af0c8cbc92 100644 --- a/fs/xfs/xfs_itable.c +++ b/fs/xfs/xfs_itable.c @@ -18,6 +18,7 @@ #include "xfs_error.h" #include "xfs_icache.h" #include "xfs_health.h" +#include "xfs_iwalk.h" /* * Return stat information for one inode. @@ -160,7 +161,7 @@ xfs_bulkstat_one( * Loop over all clusters in a chunk for a given incore inode allocation btree * record. Do a readahead if there are any allocated inodes in that cluster. */ -STATIC void +void xfs_bulkstat_ichunk_ra( struct xfs_mount *mp, xfs_agnumber_t agno, @@ -194,7 +195,7 @@ xfs_bulkstat_ichunk_ra( * are some left allocated, update the data for the pointed-to record as well as * return the count of grabbed inodes. */ -STATIC int +int xfs_bulkstat_grab_ichunk( struct xfs_btree_cur *cur, /* btree cursor */ xfs_agino_t agino, /* starting inode of chunk */ diff --git a/fs/xfs/xfs_itable.h b/fs/xfs/xfs_itable.h index 8a822285b671..369e3f159d4e 100644 --- a/fs/xfs/xfs_itable.h +++ b/fs/xfs/xfs_itable.h @@ -84,4 +84,12 @@ xfs_inumbers( void __user *buffer, /* buffer with inode info */ inumbers_fmt_pf formatter); +/* Temporarily needed while we refactor functions. */ +struct xfs_btree_cur; +struct xfs_inobt_rec_incore; +void xfs_bulkstat_ichunk_ra(struct xfs_mount *mp, xfs_agnumber_t agno, + struct xfs_inobt_rec_incore *irec); +int xfs_bulkstat_grab_ichunk(struct xfs_btree_cur *cur, xfs_agino_t agino, + int *icount, struct xfs_inobt_rec_incore *irec); + #endif /* __XFS_ITABLE_H__ */ diff --git a/fs/xfs/xfs_iwalk.c b/fs/xfs/xfs_iwalk.c new file mode 100644 index 000000000000..304c41e6ed1d --- /dev/null +++ b/fs/xfs/xfs_iwalk.c @@ -0,0 +1,389 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2019 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_mount.h" +#include "xfs_inode.h" +#include "xfs_btree.h" +#include "xfs_ialloc.h" +#include "xfs_ialloc_btree.h" +#include "xfs_iwalk.h" +#include "xfs_itable.h" +#include "xfs_error.h" +#include "xfs_trace.h" +#include "xfs_icache.h" +#include "xfs_health.h" +#include "xfs_trans.h" + +/* + * Walking Inodes in the Filesystem + * ================================ + * + * This iterator function walks a subset of filesystem inodes in increasing + * order from @startino until there are no more inodes. For each allocated + * inode it finds, it calls a walk function with the relevant inode number and + * a pointer to caller-provided data. The walk function can return the usual + * negative error code to stop the iteration; 0 to continue the iteration; or + * XFS_IWALK_ABORT to stop the iteration. This return value is returned to the + * caller. + * + * Internally, we allow the walk function to do anything, which means that we + * cannot maintain the inobt cursor or our lock on the AGI buffer. We + * therefore cache the inobt records in kernel memory and only call the walk + * function when our memory buffer is full. @nr_recs is the number of records + * that we've cached, and @sz_recs is the size of our cache. + * + * It is the responsibility of the walk function to ensure it accesses + * allocated inodes, as the inobt records may be stale by the time they are + * acted upon. + */ + +struct xfs_iwalk_ag { + struct xfs_mount *mp; + struct xfs_trans *tp; + + /* Where do we start the traversal? */ + xfs_ino_t startino; + + /* Array of inobt records we cache. */ + struct xfs_inobt_rec_incore *recs; + + /* Number of entries allocated for the @recs array. */ + unsigned int sz_recs; + + /* Number of entries in the @recs array that are in use. */ + unsigned int nr_recs; + + /* Inode walk function and data pointer. */ + xfs_iwalk_fn iwalk_fn; + void *data; +}; + +/* Allocate memory for a walk. */ +STATIC int +xfs_iwalk_alloc( + struct xfs_iwalk_ag *iwag) +{ + size_t size; + + ASSERT(iwag->recs == NULL); + iwag->nr_recs = 0; + + /* Allocate a prefetch buffer for inobt records. */ + size = iwag->sz_recs * sizeof(struct xfs_inobt_rec_incore); + iwag->recs = kmem_alloc(size, KM_MAYFAIL); + if (iwag->recs == NULL) + return -ENOMEM; + + return 0; +} + +/* Free memory we allocated for a walk. */ +STATIC void +xfs_iwalk_free( + struct xfs_iwalk_ag *iwag) +{ + kmem_free(iwag->recs); + iwag->recs = NULL; +} + +/* For each inuse inode in each cached inobt record, call our function. */ +STATIC int +xfs_iwalk_ag_recs( + struct xfs_iwalk_ag *iwag) +{ + struct xfs_mount *mp = iwag->mp; + struct xfs_trans *tp = iwag->tp; + xfs_ino_t ino; + unsigned int i, j; + xfs_agnumber_t agno; + int error; + + agno = XFS_INO_TO_AGNO(mp, iwag->startino); + for (i = 0; i < iwag->nr_recs; i++) { + struct xfs_inobt_rec_incore *irec = &iwag->recs[i]; + + trace_xfs_iwalk_ag_rec(mp, agno, irec); + + for (j = 0; j < XFS_INODES_PER_CHUNK; j++) { + /* Skip if this inode is free */ + if (XFS_INOBT_MASK(j) & irec->ir_free) + continue; + + /* Otherwise call our function. */ + ino = XFS_AGINO_TO_INO(mp, agno, irec->ir_startino + j); + error = iwag->iwalk_fn(mp, tp, ino, iwag->data); + if (error) + return error; + } + } + + return 0; +} + +/* Delete cursor and let go of AGI. */ +static inline void +xfs_iwalk_del_inobt( + struct xfs_trans *tp, + struct xfs_btree_cur **curpp, + struct xfs_buf **agi_bpp, + int error) +{ + if (*curpp) { + xfs_btree_del_cursor(*curpp, error); + *curpp = NULL; + } + if (*agi_bpp) { + xfs_trans_brelse(tp, *agi_bpp); + *agi_bpp = NULL; + } +} + +/* + * Set ourselves up for walking inobt records starting from a given point in + * the filesystem. + * + * If caller passed in a nonzero start inode number, load the record from the + * inobt and make the record look like all the inodes before agino are free so + * that we skip them, and then move the cursor to the next inobt record. This + * is how we support starting an iwalk in the middle of an inode chunk. + * + * If the caller passed in a start number of zero, move the cursor to the first + * inobt record. + * + * The caller is responsible for cleaning up the cursor and buffer pointer + * regardless of the error status. + */ +STATIC int +xfs_iwalk_ag_start( + struct xfs_iwalk_ag *iwag, + xfs_agnumber_t agno, + xfs_agino_t agino, + struct xfs_btree_cur **curpp, + struct xfs_buf **agi_bpp, + int *has_more) +{ + struct xfs_mount *mp = iwag->mp; + struct xfs_trans *tp = iwag->tp; + int icount; + int error; + + /* Set up a fresh cursor and empty the inobt cache. */ + iwag->nr_recs = 0; + error = xfs_inobt_cur(mp, tp, agno, XFS_BTNUM_INO, curpp, agi_bpp); + if (error) + return error; + + /* Starting at the beginning of the AG? That's easy! */ + if (agino == 0) + return xfs_inobt_lookup(*curpp, 0, XFS_LOOKUP_GE, has_more); + + /* + * Otherwise, we have to grab the inobt record where we left off, stuff + * the record into our cache, and then see if there are more records. + * We require a lookup cache of at least two elements so that we don't + * have to deal with tearing down the cursor to walk the records. + */ + error = xfs_bulkstat_grab_ichunk(*curpp, agino - 1, &icount, + &iwag->recs[iwag->nr_recs]); + if (error) + return error; + if (icount) + iwag->nr_recs++; + + /* + * The prefetch calculation is supposed to give us a large enough inobt + * record cache that grab_ichunk can stage a partial first record and + * the loop body can cache a record without having to check for cache + * space until after it reads an inobt record. + */ + ASSERT(iwag->nr_recs < iwag->sz_recs); + + return xfs_btree_increment(*curpp, 0, has_more); +} + +/* + * The inobt record cache is full, so preserve the inobt cursor state and + * run callbacks on the cached inobt records. When we're done, restore the + * cursor state to wherever the cursor would have been had the cache not been + * full (and therefore we could've just incremented the cursor) if *@has_more + * is true. On exit, *@has_more will indicate whether or not the caller should + * try for more inode records. + */ +STATIC int +xfs_iwalk_run_callbacks( + struct xfs_iwalk_ag *iwag, + xfs_agnumber_t agno, + struct xfs_btree_cur **curpp, + struct xfs_buf **agi_bpp, + int *has_more) +{ + struct xfs_mount *mp = iwag->mp; + struct xfs_trans *tp = iwag->tp; + struct xfs_inobt_rec_incore *irec; + xfs_agino_t restart; + int error; + + ASSERT(iwag->nr_recs > 0); + + /* Delete cursor but remember the last record we cached... */ + xfs_iwalk_del_inobt(tp, curpp, agi_bpp, 0); + irec = &iwag->recs[iwag->nr_recs - 1]; + restart = irec->ir_startino + XFS_INODES_PER_CHUNK - 1; + + error = xfs_iwalk_ag_recs(iwag); + if (error) + return error; + + /* ...empty the cache... */ + iwag->nr_recs = 0; + + if (!has_more) + return 0; + + /* ...and recreate the cursor just past where we left off. */ + error = xfs_inobt_cur(mp, tp, agno, XFS_BTNUM_INO, curpp, agi_bpp); + if (error) + return error; + + return xfs_inobt_lookup(*curpp, restart, XFS_LOOKUP_GE, has_more); +} + +/* Walk all inodes in a single AG, from @iwag->startino to the end of the AG. */ +STATIC int +xfs_iwalk_ag( + struct xfs_iwalk_ag *iwag) +{ + struct xfs_mount *mp = iwag->mp; + struct xfs_trans *tp = iwag->tp; + struct xfs_buf *agi_bp = NULL; + struct xfs_btree_cur *cur = NULL; + xfs_agnumber_t agno; + xfs_agino_t agino; + int has_more; + int error = 0; + + /* Set up our cursor at the right place in the inode btree. */ + agno = XFS_INO_TO_AGNO(mp, iwag->startino); + agino = XFS_INO_TO_AGINO(mp, iwag->startino); + error = xfs_iwalk_ag_start(iwag, agno, agino, &cur, &agi_bp, &has_more); + + while (!error && has_more) { + struct xfs_inobt_rec_incore *irec; + + cond_resched(); + + /* Fetch the inobt record. */ + irec = &iwag->recs[iwag->nr_recs]; + error = xfs_inobt_get_rec(cur, irec, &has_more); + if (error || !has_more) + break; + + /* No allocated inodes in this chunk; skip it. */ + if (irec->ir_freecount == irec->ir_count) { + error = xfs_btree_increment(cur, 0, &has_more); + if (error) + break; + continue; + } + + /* + * Start readahead for this inode chunk in anticipation of + * walking the inodes. + */ + xfs_bulkstat_ichunk_ra(mp, agno, irec); + + /* + * If there's space in the buffer for more records, increment + * the btree cursor and grab more. + */ + if (++iwag->nr_recs < iwag->sz_recs) { + error = xfs_btree_increment(cur, 0, &has_more); + if (error || !has_more) + break; + continue; + } + + /* + * Otherwise, we need to save cursor state and run the callback + * function on the cached records. The run_callbacks function + * is supposed to return a cursor pointing to the record where + * we would be if we had been able to increment like above. + */ + ASSERT(has_more); + error = xfs_iwalk_run_callbacks(iwag, agno, &cur, &agi_bp, + &has_more); + } + + if (iwag->nr_recs == 0 || error) + goto out; + + /* Walk the unprocessed records in the cache. */ + error = xfs_iwalk_run_callbacks(iwag, agno, &cur, &agi_bp, &has_more); + +out: + xfs_iwalk_del_inobt(tp, &cur, &agi_bp, error); + return error; +} + +/* + * Given the number of inodes to prefetch, set the number of inobt records that + * we cache in memory, which controls the number of inodes we try to read + * ahead. + */ +static inline unsigned int +xfs_iwalk_prefetch( + unsigned int inode_records) +{ + return PAGE_SIZE * 4 / sizeof(struct xfs_inobt_rec_incore); +} + +/* + * Walk all inodes in the filesystem starting from @startino. The @iwalk_fn + * will be called for each allocated inode, being passed the inode's number and + * @data. @max_prefetch controls how many inobt records' worth of inodes we + * try to readahead. + */ +int +xfs_iwalk( + struct xfs_mount *mp, + struct xfs_trans *tp, + xfs_ino_t startino, + xfs_iwalk_fn iwalk_fn, + unsigned int inode_records, + void *data) +{ + struct xfs_iwalk_ag iwag = { + .mp = mp, + .tp = tp, + .iwalk_fn = iwalk_fn, + .data = data, + .startino = startino, + .sz_recs = xfs_iwalk_prefetch(inode_records), + }; + xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, startino); + int error; + + ASSERT(agno < mp->m_sb.sb_agcount); + + error = xfs_iwalk_alloc(&iwag); + if (error) + return error; + + for (; agno < mp->m_sb.sb_agcount; agno++) { + error = xfs_iwalk_ag(&iwag); + if (error) + break; + iwag.startino = XFS_AGINO_TO_INO(mp, agno + 1, 0); + } + + xfs_iwalk_free(&iwag); + return error; +} diff --git a/fs/xfs/xfs_iwalk.h b/fs/xfs/xfs_iwalk.h new file mode 100644 index 000000000000..7728dfd618a4 --- /dev/null +++ b/fs/xfs/xfs_iwalk.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2019 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#ifndef __XFS_IWALK_H__ +#define __XFS_IWALK_H__ + +/* Walk all inodes in the filesystem starting from @startino. */ +typedef int (*xfs_iwalk_fn)(struct xfs_mount *mp, struct xfs_trans *tp, + xfs_ino_t ino, void *data); +/* Return values for xfs_iwalk_fn. */ +#define XFS_IWALK_CONTINUE (XFS_ITER_CONTINUE) +#define XFS_IWALK_ABORT (XFS_ITER_ABORT) + +int xfs_iwalk(struct xfs_mount *mp, struct xfs_trans *tp, xfs_ino_t startino, + xfs_iwalk_fn iwalk_fn, unsigned int inode_records, void *data); + +#endif /* __XFS_IWALK_H__ */ diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index 65c920554b96..e61d519961a1 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -3517,6 +3517,46 @@ DEFINE_EVENT(xfs_inode_corrupt_class, name, \ DEFINE_INODE_CORRUPT_EVENT(xfs_inode_mark_sick); DEFINE_INODE_CORRUPT_EVENT(xfs_inode_mark_healthy); +TRACE_EVENT(xfs_iwalk_ag, + TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, + xfs_agino_t startino), + TP_ARGS(mp, agno, startino), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(xfs_agnumber_t, agno) + __field(xfs_agino_t, startino) + ), + TP_fast_assign( + __entry->dev = mp->m_super->s_dev; + __entry->agno = agno; + __entry->startino = startino; + ), + TP_printk("dev %d:%d agno %d startino %u", + MAJOR(__entry->dev), MINOR(__entry->dev), __entry->agno, + __entry->startino) +) + +TRACE_EVENT(xfs_iwalk_ag_rec, + TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, + struct xfs_inobt_rec_incore *irec), + TP_ARGS(mp, agno, irec), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(xfs_agnumber_t, agno) + __field(xfs_agino_t, startino) + __field(uint64_t, freemask) + ), + TP_fast_assign( + __entry->dev = mp->m_super->s_dev; + __entry->agno = agno; + __entry->startino = irec->ir_startino; + __entry->freemask = irec->ir_free; + ), + TP_printk("dev %d:%d agno %d startino %u freemask 0x%llx", + MAJOR(__entry->dev), MINOR(__entry->dev), __entry->agno, + __entry->startino, __entry->freemask) +) + #endif /* _TRACE_XFS_H */ #undef TRACE_INCLUDE_PATH -- cgit v1.2.3