xfsprogs: make static things static

[thirdparty/xfsprogs-dev.git] / libxfs / rdwr.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * All Rights Reserved.
 */


#include "libxfs_priv.h"
#include "init.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_buf.h"
#include "xfs_inode_fork.h"
#include "xfs_inode.h"
#include "xfs_trans.h"

#include "libxfs.h"             /* for LIBXFS_EXIT_ON_FAILURE */

/*
 * Important design/architecture note:
 *
 * The userspace code that uses the buffer cache is much less constrained than
 * the kernel code. The userspace code is pretty nasty in places, especially
 * when it comes to buffer error handling.  Very little of the userspace code
 * outside libxfs clears bp->b_error - very little code even checks it - so the
 * libxfs code is tripping on stale errors left by the userspace code.
 *
 * We can't clear errors or zero buffer contents in libxfs_getbuf-* like we do
 * in the kernel, because those functions are used by the libxfs_readbuf_*
 * functions and hence need to leave the buffers unchanged on cache hits. This
 * is actually the only way to gather a write error from a libxfs_writebuf()
 * call - you need to get the buffer again so you can check bp->b_error field -
 * assuming that the buffer is still in the cache when you check, that is.
 *
 * This is very different to the kernel code which does not release buffers on a
 * write so we can wait on IO and check errors. The kernel buffer cache also
 * guarantees a buffer of a known initial state from xfs_buf_get() even on a
 * cache hit.
 *
 * IOWs, userspace is behaving quite differently to the kernel and as a result
 * it leaks errors from reads, invalidations and writes through
 * libxfs_getbuf/libxfs_readbuf.
 *
 * The result of this is that until the userspace code outside libxfs is cleaned
 * up, functions that release buffers from userspace control (i.e
 * libxfs_writebuf/libxfs_putbuf) need to zero bp->b_error to prevent
 * propagation of stale errors into future buffer operations.
 */

#define BDSTRAT_SIZE    (256 * 1024)

#define IO_BCOMPARE_CHECK

/* XXX: (dgc) Propagate errors, only exit if fail-on-error flag set */
int
libxfs_device_zero(struct xfs_buftarg *btp, xfs_daddr_t start, uint len)
{
        xfs_off_t       start_offset, end_offset, offset;
        ssize_t         zsize, bytes;
        char            *z;
        int             fd;

        zsize = min(BDSTRAT_SIZE, BBTOB(len));
        if ((z = memalign(libxfs_device_alignment(), zsize)) == NULL) {
                fprintf(stderr,
                        _("%s: %s can't memalign %d bytes: %s\n"),
                        progname, __FUNCTION__, (int)zsize, strerror(errno));
                exit(1);
        }
        memset(z, 0, zsize);

        fd = libxfs_device_to_fd(btp->dev);
        start_offset = LIBXFS_BBTOOFF64(start);

        if ((lseek(fd, start_offset, SEEK_SET)) < 0) {
                fprintf(stderr, _("%s: %s seek to offset %llu failed: %s\n"),
                        progname, __FUNCTION__,
                        (unsigned long long)start_offset, strerror(errno));
                exit(1);
        }

        end_offset = LIBXFS_BBTOOFF64(start + len) - start_offset;
        for (offset = 0; offset < end_offset; ) {
                bytes = min((ssize_t)(end_offset - offset), zsize);
                if ((bytes = write(fd, z, bytes)) < 0) {
                        fprintf(stderr, _("%s: %s write failed: %s\n"),
                                progname, __FUNCTION__, strerror(errno));
                        exit(1);
                } else if (bytes == 0) {
                        fprintf(stderr, _("%s: %s not progressing?\n"),
                                progname, __FUNCTION__);
                        exit(1);
                }
                offset += bytes;
        }
        free(z);
        return 0;
}

static void unmount_record(void *p)
{
        xlog_op_header_t        *op = (xlog_op_header_t *)p;
        /* the data section must be 32 bit size aligned */
        struct {
            uint16_t magic;
            uint16_t pad1;
            uint32_t pad2; /* may as well make it 64 bits */
        } magic = { XLOG_UNMOUNT_TYPE, 0, 0 };

        memset(p, 0, BBSIZE);
        /* dummy tid to mark this as written from userspace */
        op->oh_tid = cpu_to_be32(0xb0c0d0d0);
        op->oh_len = cpu_to_be32(sizeof(magic));
        op->oh_clientid = XFS_LOG;
        op->oh_flags = XLOG_UNMOUNT_TRANS;
        op->oh_res2 = 0;

        /* and the data for this op */
        memcpy((char *)p + sizeof(xlog_op_header_t), &magic, sizeof(magic));
}

static char *next(
        char            *ptr,
        int             offset,
        void            *private)
{
        struct xfs_buf  *buf = (struct xfs_buf *)private;

        if (buf &&
            (buf->b_bcount < (int)(ptr - (char *)buf->b_addr) + offset))
                abort();

        return ptr + offset;
}

/*
 * Format the log. The caller provides either a buftarg which is used to access
 * the log via buffers or a direct pointer to a buffer that encapsulates the
 * entire log.
 */
int
libxfs_log_clear(
        struct xfs_buftarg      *btp,
        char                    *dptr,
        xfs_daddr_t             start,
        uint                    length,         /* basic blocks */
        uuid_t                  *fs_uuid,
        int                     version,
        int                     sunit,          /* bytes */
        int                     fmt,
        int                     cycle,
        bool                    max)
{
        struct xfs_buf          *bp = NULL;
        int                     len;
        xfs_lsn_t               lsn;
        xfs_lsn_t               tail_lsn;
        xfs_daddr_t             blk;
        xfs_daddr_t             end_blk;
        char                    *ptr;

        if (((btp && dptr) || (!btp && !dptr)) ||
            (btp && !btp->dev) || !fs_uuid)
                return -EINVAL;

        /* first zero the log */
        if (btp)
                libxfs_device_zero(btp, start, length);
        else
                memset(dptr, 0, BBTOB(length));

        /*
         * Initialize the log record length and LSNs. XLOG_INIT_CYCLE is a
         * special reset case where we only write a single record where the lsn
         * and tail_lsn match. Otherwise, the record lsn starts at block 0 of
         * the specified cycle and points tail_lsn at the last record of the
         * previous cycle.
         */
        len = ((version == 2) && sunit) ? BTOBB(sunit) : 2;
        len = max(len, 2);
        lsn = xlog_assign_lsn(cycle, 0);
        if (cycle == XLOG_INIT_CYCLE)
                tail_lsn = lsn;
        else
                tail_lsn = xlog_assign_lsn(cycle - 1, length - len);

        /* write out the first log record */
        ptr = dptr;
        if (btp) {
                bp = libxfs_getbufr(btp, start, len);
                ptr = bp->b_addr;
        }
        libxfs_log_header(ptr, fs_uuid, version, sunit, fmt, lsn, tail_lsn,
                          next, bp);
        if (bp) {
                bp->b_flags |= LIBXFS_B_DIRTY;
                libxfs_putbufr(bp);
        }

        /*
         * There's nothing else to do if this is a log reset. The kernel detects
         * the rest of the log is zeroed and starts at cycle 1.
         */
        if (cycle == XLOG_INIT_CYCLE)
                return 0;

        /*
         * Bump the record size for a full log format if the caller allows it.
         * This is primarily for performance reasons and most callers don't care
         * about record size since the log is clean after we're done.
         */
        if (max)
                len = BTOBB(BDSTRAT_SIZE);

        /*
         * Otherwise, fill everything beyond the initial record with records of
         * the previous cycle so the kernel head/tail detection works correctly.
         *
         * We don't particularly care about the record size or content here.
         * It's only important that the headers are in place such that the
         * kernel finds 1.) a clean log and 2.) the correct current cycle value.
         * Therefore, bump up the record size to the max to use larger I/Os and
         * improve performance.
         */
        cycle--;
        blk = start + len;
        if (dptr)
                dptr += BBTOB(len);
        end_blk = start + length;

        len = min(end_blk - blk, len);
        while (blk < end_blk) {
                lsn = xlog_assign_lsn(cycle, blk - start);
                tail_lsn = xlog_assign_lsn(cycle, blk - start - len);

                ptr = dptr;
                if (btp) {
                        bp = libxfs_getbufr(btp, blk, len);
                        ptr = bp->b_addr;
                }
                /*
                 * Note: pass the full buffer length as the sunit to initialize
                 * the entire buffer.
                 */
                libxfs_log_header(ptr, fs_uuid, version, BBTOB(len), fmt, lsn,
                                  tail_lsn, next, bp);
                if (bp) {
                        bp->b_flags |= LIBXFS_B_DIRTY;
                        libxfs_putbufr(bp);
                }

                blk += len;
                if (dptr)
                        dptr += BBTOB(len);
                len = min(end_blk - blk, len);
        }

        return 0;
}

int
libxfs_log_header(
        char                    *caddr,
        uuid_t                  *fs_uuid,
        int                     version,
        int                     sunit,
        int                     fmt,
        xfs_lsn_t               lsn,
        xfs_lsn_t               tail_lsn,
        libxfs_get_block_t      *nextfunc,
        void                    *private)
{
        xlog_rec_header_t       *head = (xlog_rec_header_t *)caddr;
        char                    *p = caddr;
        __be32                  cycle_lsn;
        int                     i, len;
        int                     hdrs = 1;

        if (lsn == NULLCOMMITLSN)
                lsn = xlog_assign_lsn(XLOG_INIT_CYCLE, 0);
        if (tail_lsn == NULLCOMMITLSN)
                tail_lsn = lsn;

        len = ((version == 2) && sunit) ? BTOBB(sunit) : 1;

        memset(p, 0, BBSIZE);
        head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
        head->h_cycle = cpu_to_be32(CYCLE_LSN(lsn));
        head->h_version = cpu_to_be32(version);
        head->h_crc = cpu_to_le32(0);
        head->h_prev_block = cpu_to_be32(-1);
        head->h_num_logops = cpu_to_be32(1);
        head->h_fmt = cpu_to_be32(fmt);
        head->h_size = cpu_to_be32(max(sunit, XLOG_BIG_RECORD_BSIZE));

        head->h_lsn = cpu_to_be64(lsn);
        head->h_tail_lsn = cpu_to_be64(tail_lsn);

        memcpy(&head->h_fs_uuid, fs_uuid, sizeof(uuid_t));

        /*
         * The kernel expects to see either a log record header magic value or
         * the LSN cycle at the top of every log block. The first word of each
         * non-header block is copied to the record headers and replaced with
         * the cycle value (see xlog_[un]pack_data() and xlog_get_cycle() for
         * details).
         *
         * Even though we only ever write an unmount record (one block), we
         * support writing log records up to the max log buffer size of 256k to
         * improve log format performance. This means a record can require up
         * to 8 headers (1 rec. header + 7 ext. headers) for the packed cycle
         * data (each header supports 32k of data).
         */
        cycle_lsn = CYCLE_LSN_DISK(head->h_lsn);
        if (version == 2 && sunit > XLOG_HEADER_CYCLE_SIZE) {
                hdrs = sunit / XLOG_HEADER_CYCLE_SIZE;
                if (sunit % XLOG_HEADER_CYCLE_SIZE)
                        hdrs++;
        }

        /*
         * A fixed number of extended headers is expected based on h_size. If
         * required, format those now so the unmount record is located
         * correctly.
         *
         * Since we only write an unmount record, we only need one h_cycle_data
         * entry for the unmount record block. The subsequent record data
         * blocks are zeroed, which means we can stamp them directly with the
         * cycle and zero the rest of the cycle data in the extended headers.
         */
        if (hdrs > 1) {
                for (i = 1; i < hdrs; i++) {
                        p = nextfunc(p, BBSIZE, private);
                        memset(p, 0, BBSIZE);
                        /* xlog_rec_ext_header.xh_cycle */
                        *(__be32 *)p = cycle_lsn;
                }
        }

        /*
         * The total length is the max of the stripe unit or 2 basic block
         * minimum (1 hdr blk + 1 data blk). The record length is the total
         * minus however many header blocks are required.
         */
        head->h_len = cpu_to_be32(max(BBTOB(2), sunit) - hdrs * BBSIZE);

        /*
         * Write out the unmount record, pack the first word into the record
         * header and stamp the block with the cycle.
         */
        p = nextfunc(p, BBSIZE, private);
        unmount_record(p);

        head->h_cycle_data[0] = *(__be32 *)p;
        *(__be32 *)p = cycle_lsn;

        /*
         * Finally, zero all remaining blocks in the record and stamp each with
         * the cycle. We don't need to pack any of these blocks because the
         * cycle data in the headers has already been zeroed.
         */
        len = max(len, hdrs + 1);
        for (i = hdrs + 1; i < len; i++) {
                p = nextfunc(p, BBSIZE, private);
                memset(p, 0, BBSIZE);
                *(__be32 *)p = cycle_lsn;
        }

        return BBTOB(len);
}

/*
 * Simple I/O (buffer cache) interface
 */


#ifdef XFS_BUF_TRACING

#undef libxfs_readbuf
#undef libxfs_readbuf_map
#undef libxfs_writebuf
#undef libxfs_getbuf
#undef libxfs_getbuf_map
#undef libxfs_getbuf_flags
#undef libxfs_putbuf

xfs_buf_t       *libxfs_readbuf(struct xfs_buftarg *, xfs_daddr_t, int, int,
                                const struct xfs_buf_ops *);
xfs_buf_t       *libxfs_readbuf_map(struct xfs_buftarg *, struct xfs_buf_map *,
                                int, int, const struct xfs_buf_ops *);
int             libxfs_writebuf(xfs_buf_t *, int);
xfs_buf_t       *libxfs_getbuf(struct xfs_buftarg *, xfs_daddr_t, int);
xfs_buf_t       *libxfs_getbuf_map(struct xfs_buftarg *, struct xfs_buf_map *,
                                int, int);
xfs_buf_t       *libxfs_getbuf_flags(struct xfs_buftarg *, xfs_daddr_t, int,
                                unsigned int);
void            libxfs_putbuf (xfs_buf_t *);

#define __add_trace(bp, func, file, line)       \
do {                                            \
        if (bp) {                               \
                (bp)->b_func = (func);          \
                (bp)->b_file = (file);          \
                (bp)->b_line = (line);          \
        }                                       \
} while (0)

xfs_buf_t *
libxfs_trace_readbuf(const char *func, const char *file, int line,
                struct xfs_buftarg *btp, xfs_daddr_t blkno, int len, int flags,
                const struct xfs_buf_ops *ops)
{
        xfs_buf_t       *bp = libxfs_readbuf(btp, blkno, len, flags, ops);
        __add_trace(bp, func, file, line);
        return bp;
}

xfs_buf_t *
libxfs_trace_readbuf_map(const char *func, const char *file, int line,
                struct xfs_buftarg *btp, struct xfs_buf_map *map, int nmaps, int flags,
                const struct xfs_buf_ops *ops)
{
        xfs_buf_t       *bp = libxfs_readbuf_map(btp, map, nmaps, flags, ops);
        __add_trace(bp, func, file, line);
        return bp;
}

int
libxfs_trace_writebuf(const char *func, const char *file, int line, xfs_buf_t *bp, int flags)
{
        __add_trace(bp, func, file, line);
        return libxfs_writebuf(bp, flags);
}

xfs_buf_t *
libxfs_trace_getbuf(const char *func, const char *file, int line,
                struct xfs_buftarg *btp, xfs_daddr_t blkno, int len)
{
        xfs_buf_t       *bp = libxfs_getbuf(btp, blkno, len);
        __add_trace(bp, func, file, line);
        return bp;
}

xfs_buf_t *
libxfs_trace_getbuf_map(const char *func, const char *file, int line,
                struct xfs_buftarg *btp, struct xfs_buf_map *map, int nmaps,
                int flags)
{
        xfs_buf_t       *bp = libxfs_getbuf_map(btp, map, nmaps, flags);
        __add_trace(bp, func, file, line);
        return bp;
}

xfs_buf_t *
libxfs_trace_getbuf_flags(const char *func, const char *file, int line,
                struct xfs_buftarg *btp, xfs_daddr_t blkno, int len, unsigned int flags)
{
        xfs_buf_t       *bp = libxfs_getbuf_flags(btp, blkno, len, flags);
        __add_trace(bp, func, file, line);
        return bp;
}

void
libxfs_trace_putbuf(const char *func, const char *file, int line, xfs_buf_t *bp)
{
        __add_trace(bp, func, file, line);
        libxfs_putbuf(bp);
}


#endif


xfs_buf_t *
libxfs_getsb(xfs_mount_t *mp, int flags)
{
        return libxfs_readbuf(mp->m_ddev_targp, XFS_SB_DADDR,
                                XFS_FSS_TO_BB(mp, 1), flags, &xfs_sb_buf_ops);
}

kmem_zone_t                     *xfs_buf_zone;

static struct cache_mru         xfs_buf_freelist =
        {{&xfs_buf_freelist.cm_list, &xfs_buf_freelist.cm_list},
         0, PTHREAD_MUTEX_INITIALIZER };

/*
 * The bufkey is used to pass the new buffer information to the cache object
 * allocation routine. Because discontiguous buffers need to pass different
 * information, we need fields to pass that information. However, because the
 * blkno and bblen is needed for the initial cache entry lookup (i.e. for
 * bcompare) the fact that the map/nmaps is non-null to switch to discontiguous
 * buffer initialisation instead of a contiguous buffer.
 */
struct xfs_bufkey {
        struct xfs_buftarg      *buftarg;
        xfs_daddr_t             blkno;
        unsigned int            bblen;
        struct xfs_buf_map      *map;
        int                     nmaps;
};

/*  2^63 + 2^61 - 2^57 + 2^54 - 2^51 - 2^18 + 1 */
#define GOLDEN_RATIO_PRIME      0x9e37fffffffc0001UL
#define CACHE_LINE_SIZE         64
static unsigned int
libxfs_bhash(cache_key_t key, unsigned int hashsize, unsigned int hashshift)
{
        uint64_t        hashval = ((struct xfs_bufkey *)key)->blkno;
        uint64_t        tmp;

        tmp = hashval ^ (GOLDEN_RATIO_PRIME + hashval) / CACHE_LINE_SIZE;
        tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> hashshift);
        return tmp % hashsize;
}

static int
libxfs_bcompare(struct cache_node *node, cache_key_t key)
{
        struct xfs_buf  *bp = (struct xfs_buf *)node;
        struct xfs_bufkey *bkey = (struct xfs_bufkey *)key;

        if (bp->b_target->dev == bkey->buftarg->dev &&
            bp->b_bn == bkey->blkno) {
                if (bp->b_bcount == BBTOB(bkey->bblen))
                        return CACHE_HIT;
#ifdef IO_BCOMPARE_CHECK
                if (!(libxfs_bcache->c_flags & CACHE_MISCOMPARE_PURGE)) {
                        fprintf(stderr,
        "%lx: Badness in key lookup (length)\n"
        "bp=(bno 0x%llx, len %u bytes) key=(bno 0x%llx, len %u bytes)\n",
                                pthread_self(),
                                (unsigned long long)bp->b_bn, (int)bp->b_bcount,
                                (unsigned long long)bkey->blkno,
                                BBTOB(bkey->bblen));
                }
#endif
                return CACHE_PURGE;
        }
        return CACHE_MISS;
}

static void
libxfs_bprint(xfs_buf_t *bp)
{
        fprintf(stderr, "Buffer %p blkno=%llu bytes=%u flags=0x%x count=%u\n",
                bp, (unsigned long long)bp->b_bn, (unsigned)bp->b_bcount,
                bp->b_flags, bp->b_node.cn_count);
}

static void
__initbuf(xfs_buf_t *bp, struct xfs_buftarg *btp, xfs_daddr_t bno,
                unsigned int bytes)
{
        bp->b_flags = 0;
        bp->b_bn = bno;
        bp->b_bcount = bytes;
        bp->b_length = BTOBB(bytes);
        bp->b_target = btp;
        bp->b_error = 0;
        if (!bp->b_addr)
                bp->b_addr = memalign(libxfs_device_alignment(), bytes);
        if (!bp->b_addr) {
                fprintf(stderr,
                        _("%s: %s can't memalign %u bytes: %s\n"),
                        progname, __FUNCTION__, bytes,
                        strerror(errno));
                exit(1);
        }
        memset(bp->b_addr, 0, bytes);
#ifdef XFS_BUF_TRACING
        list_head_init(&bp->b_lock_list);
#endif
        pthread_mutex_init(&bp->b_lock, NULL);
        bp->b_holder = 0;
        bp->b_recur = 0;
        bp->b_ops = NULL;

        if (!bp->b_maps) {
                bp->b_nmaps = 1;
                bp->b_maps = &bp->__b_map;
                bp->b_maps[0].bm_bn = bp->b_bn;
                bp->b_maps[0].bm_len = bp->b_length;
        }
}

static void
libxfs_initbuf(xfs_buf_t *bp, struct xfs_buftarg *btp, xfs_daddr_t bno,
                unsigned int bytes)
{
        __initbuf(bp, btp, bno, bytes);
}

static void
libxfs_initbuf_map(xfs_buf_t *bp, struct xfs_buftarg *btp,
                struct xfs_buf_map *map, int nmaps)
{
        unsigned int bytes = 0;
        int i;

        bytes = sizeof(struct xfs_buf_map) * nmaps;
        bp->b_maps = malloc(bytes);
        if (!bp->b_maps) {
                fprintf(stderr,
                        _("%s: %s can't malloc %u bytes: %s\n"),
                        progname, __FUNCTION__, bytes,
                        strerror(errno));
                exit(1);
        }
        bp->b_nmaps = nmaps;

        bytes = 0;
        for ( i = 0; i < nmaps; i++) {
                bp->b_maps[i].bm_bn = map[i].bm_bn;
                bp->b_maps[i].bm_len = map[i].bm_len;
                bytes += BBTOB(map[i].bm_len);
        }

        __initbuf(bp, btp, map[0].bm_bn, bytes);
        bp->b_flags |= LIBXFS_B_DISCONTIG;
}

static xfs_buf_t *
__libxfs_getbufr(int blen)
{
        xfs_buf_t       *bp;

        /*
         * first look for a buffer that can be used as-is,
         * if one cannot be found, see if there is a buffer,
         * and if so, free its buffer and set b_addr to NULL
         * before calling libxfs_initbuf.
         */
        pthread_mutex_lock(&xfs_buf_freelist.cm_mutex);
        if (!list_empty(&xfs_buf_freelist.cm_list)) {
                list_for_each_entry(bp, &xfs_buf_freelist.cm_list, b_node.cn_mru) {
                        if (bp->b_bcount == blen) {
                                list_del_init(&bp->b_node.cn_mru);
                                break;
                        }
                }
                if (&bp->b_node.cn_mru == &xfs_buf_freelist.cm_list) {
                        bp = list_entry(xfs_buf_freelist.cm_list.next,
                                        xfs_buf_t, b_node.cn_mru);
                        list_del_init(&bp->b_node.cn_mru);
                        free(bp->b_addr);
                        bp->b_addr = NULL;
                        if (bp->b_maps != &bp->__b_map)
                                free(bp->b_maps);
                        bp->b_maps = NULL;
                }
        } else
                bp = kmem_zone_zalloc(xfs_buf_zone, 0);
        pthread_mutex_unlock(&xfs_buf_freelist.cm_mutex);
        bp->b_ops = NULL;
        if (bp->b_flags & LIBXFS_B_DIRTY)
                fprintf(stderr, "found dirty buffer (bulk) on free list!");

        return bp;
}

xfs_buf_t *
libxfs_getbufr(struct xfs_buftarg *btp, xfs_daddr_t blkno, int bblen)
{
        xfs_buf_t       *bp;
        int             blen = BBTOB(bblen);

        bp =__libxfs_getbufr(blen);
        if (bp)
                libxfs_initbuf(bp, btp, blkno, blen);
#ifdef IO_DEBUG
        printf("%lx: %s: allocated %u bytes buffer, key=0x%llx(0x%llx), %p\n",
                pthread_self(), __FUNCTION__, blen,
                (long long)LIBXFS_BBTOOFF64(blkno), (long long)blkno, bp);
#endif

        return bp;
}

static xfs_buf_t *
libxfs_getbufr_map(struct xfs_buftarg *btp, xfs_daddr_t blkno, int bblen,
                struct xfs_buf_map *map, int nmaps)
{
        xfs_buf_t       *bp;
        int             blen = BBTOB(bblen);

        if (!map || !nmaps) {
                fprintf(stderr,
                        _("%s: %s invalid map %p or nmaps %d\n"),
                        progname, __FUNCTION__, map, nmaps);
                exit(1);
        }

        if (blkno != map[0].bm_bn) {
                fprintf(stderr,
                        _("%s: %s map blkno 0x%llx doesn't match key 0x%llx\n"),
                        progname, __FUNCTION__, (long long)map[0].bm_bn,
                        (long long)blkno);
                exit(1);
        }

        bp =__libxfs_getbufr(blen);
        if (bp)
                libxfs_initbuf_map(bp, btp, map, nmaps);
#ifdef IO_DEBUG
        printf("%lx: %s: allocated %u bytes buffer, key=0x%llx(0x%llx), %p\n",
                pthread_self(), __FUNCTION__, blen,
                (long long)LIBXFS_BBTOOFF64(blkno), (long long)blkno, bp);
#endif

        return bp;
}

#ifdef XFS_BUF_TRACING
struct list_head        lock_buf_list = {&lock_buf_list, &lock_buf_list};
int                     lock_buf_count = 0;
#endif

extern int     use_xfs_buf_lock;

static struct xfs_buf *
__cache_lookup(struct xfs_bufkey *key, unsigned int flags)
{
        struct xfs_buf  *bp;

        cache_node_get(libxfs_bcache, key, (struct cache_node **)&bp);
        if (!bp)
                return NULL;

        if (use_xfs_buf_lock) {
                int ret;

                ret = pthread_mutex_trylock(&bp->b_lock);
                if (ret) {
                        ASSERT(ret == EAGAIN);
                        if (flags & LIBXFS_GETBUF_TRYLOCK)
                                goto out_put;

                        if (pthread_equal(bp->b_holder, pthread_self())) {
                                fprintf(stderr,
        _("Warning: recursive buffer locking at block %" PRIu64 " detected\n"),
                                        key->blkno);
                                bp->b_recur++;
                                return bp;
                        } else {
                                pthread_mutex_lock(&bp->b_lock);
                        }
                }

                bp->b_holder = pthread_self();
        }

        cache_node_set_priority(libxfs_bcache, (struct cache_node *)bp,
                cache_node_get_priority((struct cache_node *)bp) -
                                                CACHE_PREFETCH_PRIORITY);
#ifdef XFS_BUF_TRACING
        pthread_mutex_lock(&libxfs_bcache->c_mutex);
        lock_buf_count++;
        list_add(&bp->b_lock_list, &lock_buf_list);
        pthread_mutex_unlock(&libxfs_bcache->c_mutex);
#endif
#ifdef IO_DEBUG
        printf("%lx %s: hit buffer %p for bno = 0x%llx/0x%llx\n",
                pthread_self(), __FUNCTION__,
                bp, bp->b_bn, (long long)LIBXFS_BBTOOFF64(key->blkno));
#endif

        return bp;
out_put:
        cache_node_put(libxfs_bcache, (struct cache_node *)bp);
        return NULL;
}

struct xfs_buf *
libxfs_getbuf_flags(struct xfs_buftarg *btp, xfs_daddr_t blkno, int len,
                unsigned int flags)
{
        struct xfs_bufkey key = {NULL};

        key.buftarg = btp;
        key.blkno = blkno;
        key.bblen = len;

        return __cache_lookup(&key, flags);
}

/*
 * Clean the buffer flags for libxfs_getbuf*(), which wants to return
 * an unused buffer with clean state.  This prevents CRC errors on a
 * re-read of a corrupt block that was prefetched and freed.  This
 * can happen with a massively corrupt directory that is discarded,
 * but whose blocks are then recycled into expanding lost+found.
 *
 * Note however that if the buffer's dirty (prefetch calls getbuf)
 * we'll leave the state alone because we don't want to discard blocks
 * that have been fixed.
 */
static void
reset_buf_state(
        struct xfs_buf  *bp)
{
        if (bp && !(bp->b_flags & LIBXFS_B_DIRTY))
                bp->b_flags &= ~(LIBXFS_B_UNCHECKED | LIBXFS_B_STALE |
                                LIBXFS_B_UPTODATE);
}

struct xfs_buf *
libxfs_getbuf(struct xfs_buftarg *btp, xfs_daddr_t blkno, int len)
{
        struct xfs_buf  *bp;

        bp = libxfs_getbuf_flags(btp, blkno, len, 0);
        reset_buf_state(bp);
        return bp;
}

static struct xfs_buf *
__libxfs_getbuf_map(struct xfs_buftarg *btp, struct xfs_buf_map *map,
                    int nmaps, int flags)
{
        struct xfs_bufkey key = {NULL};
        int i;

        if (nmaps == 1)
                return libxfs_getbuf_flags(btp, map[0].bm_bn, map[0].bm_len,
                                           flags);

        key.buftarg = btp;
        key.blkno = map[0].bm_bn;
        for (i = 0; i < nmaps; i++) {
                key.bblen += map[i].bm_len;
        }
        key.map = map;
        key.nmaps = nmaps;

        return __cache_lookup(&key, flags);
}

struct xfs_buf *
libxfs_getbuf_map(struct xfs_buftarg *btp, struct xfs_buf_map *map,
                  int nmaps, int flags)
{
        struct xfs_buf  *bp;

        bp = __libxfs_getbuf_map(btp, map, nmaps, flags);
        reset_buf_state(bp);
        return bp;
}

void
libxfs_putbuf(xfs_buf_t *bp)
{
        /*
         * ensure that any errors on this use of the buffer don't carry
         * over to the next user.
         */
        bp->b_error = 0;

#ifdef XFS_BUF_TRACING
        pthread_mutex_lock(&libxfs_bcache->c_mutex);
        lock_buf_count--;
        ASSERT(lock_buf_count >= 0);
        list_del_init(&bp->b_lock_list);
        pthread_mutex_unlock(&libxfs_bcache->c_mutex);
#endif
        if (use_xfs_buf_lock) {
                if (bp->b_recur) {
                        bp->b_recur--;
                } else {
                        bp->b_holder = 0;
                        pthread_mutex_unlock(&bp->b_lock);
                }
        }

        cache_node_put(libxfs_bcache, (struct cache_node *)bp);
}

void
libxfs_purgebuf(xfs_buf_t *bp)
{
        struct xfs_bufkey key = {NULL};

        key.buftarg = bp->b_target;
        key.blkno = bp->b_bn;
        key.bblen = bp->b_length;

        cache_node_purge(libxfs_bcache, &key, (struct cache_node *)bp);
}

static struct cache_node *
libxfs_balloc(cache_key_t key)
{
        struct xfs_bufkey *bufkey = (struct xfs_bufkey *)key;

        if (bufkey->map)
                return (struct cache_node *)
                       libxfs_getbufr_map(bufkey->buftarg,
                                          bufkey->blkno, bufkey->bblen,
                                          bufkey->map, bufkey->nmaps);
        return (struct cache_node *)libxfs_getbufr(bufkey->buftarg,
                                          bufkey->blkno, bufkey->bblen);
}


static int
__read_buf(int fd, void *buf, int len, off64_t offset, int flags)
{
        int     sts;

        sts = pread(fd, buf, len, offset);
        if (sts < 0) {
                int error = errno;
                fprintf(stderr, _("%s: read failed: %s\n"),
                        progname, strerror(error));
                if (flags & LIBXFS_EXIT_ON_FAILURE)
                        exit(1);
                return -error;
        } else if (sts != len) {
                fprintf(stderr, _("%s: error - read only %d of %d bytes\n"),
                        progname, sts, len);
                if (flags & LIBXFS_EXIT_ON_FAILURE)
                        exit(1);
                return -EIO;
        }
        return 0;
}

int
libxfs_readbufr(struct xfs_buftarg *btp, xfs_daddr_t blkno, xfs_buf_t *bp,
                int len, int flags)
{
        int     fd = libxfs_device_to_fd(btp->dev);
        int     bytes = BBTOB(len);
        int     error;

        ASSERT(BBTOB(len) <= bp->b_bcount);

        error = __read_buf(fd, bp->b_addr, bytes, LIBXFS_BBTOOFF64(blkno), flags);
        if (!error &&
            bp->b_target->dev == btp->dev &&
            bp->b_bn == blkno &&
            bp->b_bcount == bytes)
                bp->b_flags |= LIBXFS_B_UPTODATE;
#ifdef IO_DEBUG
        printf("%lx: %s: read %u bytes, error %d, blkno=0x%llx(0x%llx), %p\n",
                pthread_self(), __FUNCTION__, bytes, error,
                (long long)LIBXFS_BBTOOFF64(blkno), (long long)blkno, bp);
#endif
        return error;
}

void
libxfs_readbuf_verify(struct xfs_buf *bp, const struct xfs_buf_ops *ops)
{
        if (!ops)
                return;
        bp->b_ops = ops;
        bp->b_ops->verify_read(bp);
        bp->b_flags &= ~LIBXFS_B_UNCHECKED;
}


xfs_buf_t *
libxfs_readbuf(struct xfs_buftarg *btp, xfs_daddr_t blkno, int len, int flags,
                const struct xfs_buf_ops *ops)
{
        xfs_buf_t       *bp;
        int             error;

        bp = libxfs_getbuf_flags(btp, blkno, len, 0);
        if (!bp)
                return NULL;

        /*
         * if the buffer was prefetched, it is likely that it was not validated.
         * Hence if we are supplied an ops function and the buffer is marked as
         * unchecked, we need to validate it now.
         *
         * We do this verification even if the buffer is dirty - the
         * verification is almost certainly going to fail the CRC check in this
         * case as a dirty buffer has not had the CRC recalculated. However, we
         * should not be dirtying unchecked buffers and therefore failing it
         * here because it's dirty and unchecked indicates we've screwed up
         * somewhere else.
         */
        bp->b_error = 0;
        if ((bp->b_flags & (LIBXFS_B_UPTODATE|LIBXFS_B_DIRTY))) {
                if (bp->b_flags & LIBXFS_B_UNCHECKED)
                        libxfs_readbuf_verify(bp, ops);
                return bp;
        }

        /*
         * Set the ops on a cache miss (i.e. first physical read) as the
         * verifier may change the ops to match the type of buffer it contains.
         * A cache hit might reset the verifier to the original type if we set
         * it again, but it won't get called again and set to match the buffer
         * contents. *cough* xfs_da_node_buf_ops *cough*.
         */
        error = libxfs_readbufr(btp, blkno, bp, len, flags);
        if (error)
                bp->b_error = error;
        else
                libxfs_readbuf_verify(bp, ops);
        return bp;
}

int
libxfs_readbufr_map(struct xfs_buftarg *btp, struct xfs_buf *bp, int flags)
{
        int     fd;
        int     error = 0;
        void    *buf;
        int     i;

        fd = libxfs_device_to_fd(btp->dev);
        buf = bp->b_addr;
        for (i = 0; i < bp->b_nmaps; i++) {
                off64_t offset = LIBXFS_BBTOOFF64(bp->b_maps[i].bm_bn);
                int len = BBTOB(bp->b_maps[i].bm_len);

                error = __read_buf(fd, buf, len, offset, flags);
                if (error) {
                        bp->b_error = error;
                        break;
                }
                buf += len;
        }

        if (!error)
                bp->b_flags |= LIBXFS_B_UPTODATE;
#ifdef IO_DEBUG
        printf("%lx: %s: read %lu bytes, error %d, blkno=%llu(%llu), %p\n",
                pthread_self(), __FUNCTION__, buf - (char *)bp->b_addr, error,
                (long long)LIBXFS_BBTOOFF64(bp->b_bn), (long long)bp->b_bn, bp);
#endif
        return error;
}

struct xfs_buf *
libxfs_readbuf_map(struct xfs_buftarg *btp, struct xfs_buf_map *map, int nmaps,
                int flags, const struct xfs_buf_ops *ops)
{
        struct xfs_buf  *bp;
        int             error = 0;

        if (nmaps == 1)
                return libxfs_readbuf(btp, map[0].bm_bn, map[0].bm_len,
                                        flags, ops);

        bp = __libxfs_getbuf_map(btp, map, nmaps, 0);
        if (!bp)
                return NULL;

        bp->b_error = 0;
        if ((bp->b_flags & (LIBXFS_B_UPTODATE|LIBXFS_B_DIRTY))) {
                if (bp->b_flags & LIBXFS_B_UNCHECKED)
                        libxfs_readbuf_verify(bp, ops);
                return bp;
        }
        error = libxfs_readbufr_map(btp, bp, flags);
        if (!error)
                libxfs_readbuf_verify(bp, ops);

#ifdef IO_DEBUGX
        printf("%lx: %s: read %lu bytes, error %d, blkno=%llu(%llu), %p\n",
                pthread_self(), __FUNCTION__, buf - (char *)bp->b_addr, error,
                (long long)LIBXFS_BBTOOFF64(bp->b_bn), (long long)bp->b_bn, bp);
#endif
        return bp;
}

static int
__write_buf(int fd, void *buf, int len, off64_t offset, int flags)
{
        int     sts;

        sts = pwrite(fd, buf, len, offset);
        if (sts < 0) {
                int error = errno;
                fprintf(stderr, _("%s: pwrite failed: %s\n"),
                        progname, strerror(error));
                if (flags & LIBXFS_B_EXIT)
                        exit(1);
                return -error;
        } else if (sts != len) {
                fprintf(stderr, _("%s: error - pwrite only %d of %d bytes\n"),
                        progname, sts, len);
                if (flags & LIBXFS_B_EXIT)
                        exit(1);
                return -EIO;
        }
        return 0;
}

int
libxfs_writebufr(xfs_buf_t *bp)
{
        int     fd = libxfs_device_to_fd(bp->b_target->dev);

        /*
         * we never write buffers that are marked stale. This indicates they
         * contain data that has been invalidated, and even if the buffer is
         * dirty it must *never* be written. Verifiers are wonderful for finding
         * bugs like this. Make sure the error is obvious as to the cause.
         */
        if (bp->b_flags & LIBXFS_B_STALE) {
                bp->b_error = -ESTALE;
                return bp->b_error;
        }

        /*
         * clear any pre-existing error status on the buffer. This can occur if
         * the buffer is corrupt on disk and the repair process doesn't clear
         * the error before fixing and writing it back.
         */
        bp->b_error = 0;
        if (bp->b_ops) {
                bp->b_ops->verify_write(bp);
                if (bp->b_error) {
                        fprintf(stderr,
        _("%s: write verifer failed on %s bno 0x%llx/0x%x\n"),
                                __func__, bp->b_ops->name,
                                (long long)bp->b_bn, bp->b_bcount);
                        return bp->b_error;
                }
        }

        if (!(bp->b_flags & LIBXFS_B_DISCONTIG)) {
                bp->b_error = __write_buf(fd, bp->b_addr, bp->b_bcount,
                                    LIBXFS_BBTOOFF64(bp->b_bn), bp->b_flags);
        } else {
                int     i;
                void    *buf = bp->b_addr;

                for (i = 0; i < bp->b_nmaps; i++) {
                        off64_t offset = LIBXFS_BBTOOFF64(bp->b_maps[i].bm_bn);
                        int len = BBTOB(bp->b_maps[i].bm_len);

                        bp->b_error = __write_buf(fd, buf, len, offset,
                                                  bp->b_flags);
                        if (bp->b_error)
                                break;
                        buf += len;
                }
        }

#ifdef IO_DEBUG
        printf("%lx: %s: wrote %u bytes, blkno=%llu(%llu), %p, error %d\n",
                        pthread_self(), __FUNCTION__, bp->b_bcount,
                        (long long)LIBXFS_BBTOOFF64(bp->b_bn),
                        (long long)bp->b_bn, bp, bp->b_error);
#endif
        if (!bp->b_error) {
                bp->b_flags |= LIBXFS_B_UPTODATE;
                bp->b_flags &= ~(LIBXFS_B_DIRTY | LIBXFS_B_EXIT |
                                 LIBXFS_B_UNCHECKED);
        }
        return bp->b_error;
}

int
libxfs_writebuf_int(xfs_buf_t *bp, int flags)
{
        /*
         * Clear any error hanging over from reading the buffer. This prevents
         * subsequent reads after this write from seeing stale errors.
         */
        bp->b_error = 0;
        bp->b_flags &= ~LIBXFS_B_STALE;
        bp->b_flags |= (LIBXFS_B_DIRTY | flags);
        return 0;
}

int
libxfs_writebuf(xfs_buf_t *bp, int flags)
{
#ifdef IO_DEBUG
        printf("%lx: %s: dirty blkno=%llu(%llu)\n",
                        pthread_self(), __FUNCTION__,
                        (long long)LIBXFS_BBTOOFF64(bp->b_bn),
                        (long long)bp->b_bn);
#endif
        /*
         * Clear any error hanging over from reading the buffer. This prevents
         * subsequent reads after this write from seeing stale errors.
         */
        bp->b_error = 0;
        bp->b_flags &= ~LIBXFS_B_STALE;
        bp->b_flags |= (LIBXFS_B_DIRTY | flags);
        libxfs_putbuf(bp);
        return 0;
}

void
libxfs_iomove(xfs_buf_t *bp, uint boff, int len, void *data, int flags)
{
#ifdef IO_DEBUG
        if (boff + len > bp->b_bcount) {
                printf("Badness, iomove out of range!\n"
                        "bp=(bno 0x%llx, bytes %u) range=(boff %u, bytes %u)\n",
                        (long long)bp->b_bn, bp->b_bcount, boff, len);
                abort();
        }
#endif
        switch (flags) {
        case LIBXFS_BZERO:
                memset(bp->b_addr + boff, 0, len);
                break;
        case LIBXFS_BREAD:
                memcpy(data, bp->b_addr + boff, len);
                break;
        case LIBXFS_BWRITE:
                memcpy(bp->b_addr + boff, data, len);
                break;
        }
}

static void
libxfs_brelse(
        struct cache_node       *node)
{
        struct xfs_buf          *bp = (struct xfs_buf *)node;

        if (!bp)
                return;
        if (bp->b_flags & LIBXFS_B_DIRTY)
                fprintf(stderr,
                        "releasing dirty buffer to free list!");

        pthread_mutex_lock(&xfs_buf_freelist.cm_mutex);
        list_add(&bp->b_node.cn_mru, &xfs_buf_freelist.cm_list);
        pthread_mutex_unlock(&xfs_buf_freelist.cm_mutex);
}

static unsigned int
libxfs_bulkrelse(
        struct cache            *cache,
        struct list_head        *list)
{
        xfs_buf_t               *bp;
        int                     count = 0;

        if (list_empty(list))
                return 0 ;

        list_for_each_entry(bp, list, b_node.cn_mru) {
                if (bp->b_flags & LIBXFS_B_DIRTY)
                        fprintf(stderr,
                                "releasing dirty buffer (bulk) to free list!");
                count++;
        }

        pthread_mutex_lock(&xfs_buf_freelist.cm_mutex);
        list_splice(list, &xfs_buf_freelist.cm_list);
        pthread_mutex_unlock(&xfs_buf_freelist.cm_mutex);

        return count;
}

/*
 * Free everything from the xfs_buf_freelist MRU, used at final teardown
 */
void
libxfs_bcache_free(void)
{
        struct list_head        *cm_list;
        xfs_buf_t               *bp, *next;

        cm_list = &xfs_buf_freelist.cm_list;
        list_for_each_entry_safe(bp, next, cm_list, b_node.cn_mru) {
                free(bp->b_addr);
                if (bp->b_maps != &bp->__b_map)
                        free(bp->b_maps);
                kmem_zone_free(xfs_buf_zone, bp);
        }
}

/*
 * When a buffer is marked dirty, the error is cleared. Hence if we are trying
 * to flush a buffer prior to cache reclaim that has an error on it it means
 * we've already tried to flush it and it failed. Prevent repeated corruption
 * errors from being reported by skipping such buffers - when the corruption is
 * fixed the buffer will be marked dirty again and we can write it again.
 */
static int
libxfs_bflush(
        struct cache_node       *node)
{
        struct xfs_buf          *bp = (struct xfs_buf *)node;

        if (!bp->b_error && bp->b_flags & LIBXFS_B_DIRTY)
                return libxfs_writebufr(bp);
        return bp->b_error;
}

void
libxfs_putbufr(xfs_buf_t *bp)
{
        if (bp->b_flags & LIBXFS_B_DIRTY)
                libxfs_writebufr(bp);
        libxfs_brelse((struct cache_node *)bp);
}


void
libxfs_bcache_purge(void)
{
        cache_purge(libxfs_bcache);
}

void
libxfs_bcache_flush(void)
{
        cache_flush(libxfs_bcache);
}

int
libxfs_bcache_overflowed(void)
{
        return cache_overflowed(libxfs_bcache);
}

struct cache_operations libxfs_bcache_operations = {
        .hash           = libxfs_bhash,
        .alloc          = libxfs_balloc,
        .flush          = libxfs_bflush,
        .relse          = libxfs_brelse,
        .compare        = libxfs_bcompare,
        .bulkrelse      = libxfs_bulkrelse
};


/*
 * Inode cache stubs.
 */

kmem_zone_t             *xfs_inode_zone;
extern kmem_zone_t      *xfs_ili_zone;

/*
 * If there are inline format data / attr forks attached to this inode,
 * make sure they're not corrupt.
 */
bool
libxfs_inode_verify_forks(
        struct xfs_inode        *ip,
        struct xfs_ifork_ops    *ops)
{
        struct xfs_ifork        *ifp;
        xfs_failaddr_t          fa;

        if (!ops)
                return true;

        fa = xfs_ifork_verify_data(ip, ops);
        if (fa) {
                ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
                xfs_inode_verifier_error(ip, -EFSCORRUPTED, "data fork",
                                ifp->if_u1.if_data, ifp->if_bytes, fa);
                return false;
        }

        fa = xfs_ifork_verify_attr(ip, ops);
        if (fa) {
                ifp = XFS_IFORK_PTR(ip, XFS_ATTR_FORK);
                xfs_inode_verifier_error(ip, -EFSCORRUPTED, "attr fork",
                                ifp ? ifp->if_u1.if_data : NULL,
                                ifp ? ifp->if_bytes : 0, fa);
                return false;
        }
        return true;
}

int
libxfs_iget(
        struct xfs_mount        *mp,
        struct xfs_trans        *tp,
        xfs_ino_t               ino,
        uint                    lock_flags,
        struct xfs_inode        **ipp,
        struct xfs_ifork_ops    *ifork_ops)
{
        struct xfs_inode        *ip;
        int                     error = 0;

        ip = kmem_zone_zalloc(xfs_inode_zone, 0);
        if (!ip)
                return -ENOMEM;

        ip->i_ino = ino;
        ip->i_mount = mp;
        error = xfs_iread(mp, tp, ip, 0);
        if (error) {
                kmem_zone_free(xfs_inode_zone, ip);
                *ipp = NULL;
                return error;
        }

        if (!libxfs_inode_verify_forks(ip, ifork_ops)) {
                libxfs_irele(ip);
                return -EFSCORRUPTED;
        }

        /*
         * set up the inode ops structure that the libxfs code relies on
         */
        if (XFS_ISDIR(ip))
                ip->d_ops = mp->m_dir_inode_ops;
        else
                ip->d_ops = mp->m_nondir_inode_ops;

        *ipp = ip;
        return 0;
}

static void
libxfs_idestroy(xfs_inode_t *ip)
{
        switch (VFS_I(ip)->i_mode & S_IFMT) {
                case S_IFREG:
                case S_IFDIR:
                case S_IFLNK:
                        libxfs_idestroy_fork(ip, XFS_DATA_FORK);
                        break;
        }
        if (ip->i_afp)
                libxfs_idestroy_fork(ip, XFS_ATTR_FORK);
        if (ip->i_cowfp)
                xfs_idestroy_fork(ip, XFS_COW_FORK);
}

void
libxfs_irele(
        struct xfs_inode        *ip)
{
        if (ip->i_itemp)
                kmem_zone_free(xfs_ili_zone, ip->i_itemp);
        ip->i_itemp = NULL;
        libxfs_idestroy(ip);
        kmem_zone_free(xfs_inode_zone, ip);
}