xfs_attr.c

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/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_alloc.h"
#include "xfs_inode_item.h"
#include "xfs_bmap.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_error.h"
#include "xfs_quota.h"
#include "xfs_trans_space.h"
#include "xfs_vnodeops.h"
#include "xfs_trace.h"

/*
 * xfs_attr.c
 *
 * Provide the external interfaces to manage attribute lists.
 */

/*========================================================================
 * Function prototypes for the kernel.
 *========================================================================*/

/*
 * Internal routines when attribute list fits inside the inode.
 */
STATIC int xfs_attr_shortform_addname(xfs_da_args_t *args);

/*
 * Internal routines when attribute list is one block.
 */
STATIC int xfs_attr_leaf_get(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_addname(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_list(xfs_attr_list_context_t *context);

/*
 * Internal routines when attribute list is more than one block.
 */
STATIC int xfs_attr_node_get(xfs_da_args_t *args);
STATIC int xfs_attr_node_addname(xfs_da_args_t *args);
STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
STATIC int xfs_attr_node_list(xfs_attr_list_context_t *context);
STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
STATIC int xfs_attr_refillstate(xfs_da_state_t *state);

/*
 * Routines to manipulate out-of-line attribute values.
 */
STATIC int xfs_attr_rmtval_set(xfs_da_args_t *args);
STATIC int xfs_attr_rmtval_remove(xfs_da_args_t *args);

#define ATTR_RMTVALUE_MAPSIZE   1   /* # of map entries at once */

STATIC int
xfs_attr_name_to_xname(
    struct xfs_name *xname,
    const unsigned char *aname)
{
    if (!aname)
        return EINVAL;
    xname->name = aname;
    xname->len = strlen((char *)aname);
    if (xname->len >= MAXNAMELEN)
        return EFAULT;      /* match IRIX behaviour */

    return 0;
}

STATIC int
xfs_inode_hasattr(
    struct xfs_inode    *ip)
{
    if (!XFS_IFORK_Q(ip) ||
        (ip->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
         ip->i_d.di_anextents == 0))
        return 0;
    return 1;
}

/*========================================================================
 * Overall external interface routines.
 *========================================================================*/

STATIC int
xfs_attr_get_int(
    struct xfs_inode    *ip,
    struct xfs_name     *name,
    unsigned char       *value,
    int         *valuelenp,
    int         flags)
{
    xfs_da_args_t   args;
    int             error;

    if (!xfs_inode_hasattr(ip))
        return ENOATTR;

    /*
     * Fill in the arg structure for this request.
     */
    memset((char *)&args, 0, sizeof(args));
    args.name = name->name;
    args.namelen = name->len;
    args.value = value;
    args.valuelen = *valuelenp;
    args.flags = flags;
    args.hashval = xfs_da_hashname(args.name, args.namelen);
    args.dp = ip;
    args.whichfork = XFS_ATTR_FORK;

    /*
     * Decide on what work routines to call based on the inode size.
     */
    if (ip->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
        error = xfs_attr_shortform_getvalue(&args);
    } else if (xfs_bmap_one_block(ip, XFS_ATTR_FORK)) {
        error = xfs_attr_leaf_get(&args);
    } else {
        error = xfs_attr_node_get(&args);
    }

    /*
     * Return the number of bytes in the value to the caller.
     */
    *valuelenp = args.valuelen;

    if (error == EEXIST)
        error = 0;
    return(error);
}

int
xfs_attr_get(
    xfs_inode_t *ip,
    const unsigned char *name,
    unsigned char   *value,
    int     *valuelenp,
    int     flags)
{
    int     error;
    struct xfs_name xname;

    XFS_STATS_INC(xs_attr_get);

    if (XFS_FORCED_SHUTDOWN(ip->i_mount))
        return(EIO);

    error = xfs_attr_name_to_xname(&xname, name);
    if (error)
        return error;

    xfs_ilock(ip, XFS_ILOCK_SHARED);
    error = xfs_attr_get_int(ip, &xname, value, valuelenp, flags);
    xfs_iunlock(ip, XFS_ILOCK_SHARED);
    return(error);
}

/*
 * Calculate how many blocks we need for the new attribute,
 */
STATIC int
xfs_attr_calc_size(
    struct xfs_inode    *ip,
    int         namelen,
    int         valuelen,
    int         *local)
{
    struct xfs_mount    *mp = ip->i_mount;
    int         size;
    int         nblks;

    /*
     * Determine space new attribute will use, and if it would be
     * "local" or "remote" (note: local != inline).
     */
    size = xfs_attr_leaf_newentsize(namelen, valuelen,
                    mp->m_sb.sb_blocksize, local);

    nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
    if (*local) {
        if (size > (mp->m_sb.sb_blocksize >> 1)) {
            /* Double split possible */
            nblks *= 2;
        }
    } else {
        /*
         * Out of line attribute, cannot double split, but
         * make room for the attribute value itself.
         */
        uint    dblocks = XFS_B_TO_FSB(mp, valuelen);
        nblks += dblocks;
        nblks += XFS_NEXTENTADD_SPACE_RES(mp, dblocks, XFS_ATTR_FORK);
    }

    return nblks;
}

STATIC int
xfs_attr_set_int(
    struct xfs_inode *dp,
    struct xfs_name *name,
    unsigned char   *value,
    int     valuelen,
    int     flags)
{
    xfs_da_args_t   args;
    xfs_fsblock_t   firstblock;
    xfs_bmap_free_t flist;
    int     error, err2, committed;
    xfs_mount_t *mp = dp->i_mount;
    int             rsvd = (flags & ATTR_ROOT) != 0;
    int     local;

    /*
     * Attach the dquots to the inode.
     */
    error = xfs_qm_dqattach(dp, 0);
    if (error)
        return error;

    /*
     * If the inode doesn't have an attribute fork, add one.
     * (inode must not be locked when we call this routine)
     */
    if (XFS_IFORK_Q(dp) == 0) {
        int sf_size = sizeof(xfs_attr_sf_hdr_t) +
                  XFS_ATTR_SF_ENTSIZE_BYNAME(name->len, valuelen);

        if ((error = xfs_bmap_add_attrfork(dp, sf_size, rsvd)))
            return(error);
    }

    /*
     * Fill in the arg structure for this request.
     */
    memset((char *)&args, 0, sizeof(args));
    args.name = name->name;
    args.namelen = name->len;
    args.value = value;
    args.valuelen = valuelen;
    args.flags = flags;
    args.hashval = xfs_da_hashname(args.name, args.namelen);
    args.dp = dp;
    args.firstblock = &firstblock;
    args.flist = &flist;
    args.whichfork = XFS_ATTR_FORK;
    args.op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;

    /* Size is now blocks for attribute data */
    args.total = xfs_attr_calc_size(dp, name->len, valuelen, &local);

    /*
     * Start our first transaction of the day.
     *
     * All future transactions during this code must be "chained" off
     * this one via the trans_dup() call.  All transactions will contain
     * the inode, and the inode will always be marked with trans_ihold().
     * Since the inode will be locked in all transactions, we must log
     * the inode in every transaction to let it float upward through
     * the log.
     */
    args.trans = xfs_trans_alloc(mp, XFS_TRANS_ATTR_SET);

    /*
     * Root fork attributes can use reserved data blocks for this
     * operation if necessary
     */

    if (rsvd)
        args.trans->t_flags |= XFS_TRANS_RESERVE;

    if ((error = xfs_trans_reserve(args.trans, args.total,
            XFS_ATTRSET_LOG_RES(mp, args.total), 0,
            XFS_TRANS_PERM_LOG_RES, XFS_ATTRSET_LOG_COUNT))) {
        xfs_trans_cancel(args.trans, 0);
        return(error);
    }
    xfs_ilock(dp, XFS_ILOCK_EXCL);

    error = xfs_trans_reserve_quota_nblks(args.trans, dp, args.total, 0,
                rsvd ? XFS_QMOPT_RES_REGBLKS | XFS_QMOPT_FORCE_RES :
                       XFS_QMOPT_RES_REGBLKS);
    if (error) {
        xfs_iunlock(dp, XFS_ILOCK_EXCL);
        xfs_trans_cancel(args.trans, XFS_TRANS_RELEASE_LOG_RES);
        return (error);
    }

    xfs_trans_ijoin(args.trans, dp, 0);

    /*
     * If the attribute list is non-existent or a shortform list,
     * upgrade it to a single-leaf-block attribute list.
     */
    if ((dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) ||
        ((dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS) &&
         (dp->i_d.di_anextents == 0))) {

        /*
         * Build initial attribute list (if required).
         */
        if (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS)
            xfs_attr_shortform_create(&args);

        /*
         * Try to add the attr to the attribute list in
         * the inode.
         */
        error = xfs_attr_shortform_addname(&args);
        if (error != ENOSPC) {
            /*
             * Commit the shortform mods, and we're done.
             * NOTE: this is also the error path (EEXIST, etc).
             */
            ASSERT(args.trans != NULL);

            /*
             * If this is a synchronous mount, make sure that
             * the transaction goes to disk before returning
             * to the user.
             */
            if (mp->m_flags & XFS_MOUNT_WSYNC) {
                xfs_trans_set_sync(args.trans);
            }

            if (!error && (flags & ATTR_KERNOTIME) == 0) {
                xfs_trans_ichgtime(args.trans, dp,
                            XFS_ICHGTIME_CHG);
            }
            err2 = xfs_trans_commit(args.trans,
                         XFS_TRANS_RELEASE_LOG_RES);
            xfs_iunlock(dp, XFS_ILOCK_EXCL);

            return(error == 0 ? err2 : error);
        }

        /*
         * It won't fit in the shortform, transform to a leaf block.
         * GROT: another possible req'mt for a double-split btree op.
         */
        xfs_bmap_init(args.flist, args.firstblock);
        error = xfs_attr_shortform_to_leaf(&args);
        if (!error) {
            error = xfs_bmap_finish(&args.trans, args.flist,
                        &committed);
        }
        if (error) {
            ASSERT(committed);
            args.trans = NULL;
            xfs_bmap_cancel(&flist);
            goto out;
        }

        /*
         * bmap_finish() may have committed the last trans and started
         * a new one.  We need the inode to be in all transactions.
         */
        if (committed)
            xfs_trans_ijoin(args.trans, dp, 0);

        /*
         * Commit the leaf transformation.  We'll need another (linked)
         * transaction to add the new attribute to the leaf.
         */

        error = xfs_trans_roll(&args.trans, dp);
        if (error)
            goto out;

    }

    if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
        error = xfs_attr_leaf_addname(&args);
    } else {
        error = xfs_attr_node_addname(&args);
    }
    if (error) {
        goto out;
    }

    /*
     * If this is a synchronous mount, make sure that the
     * transaction goes to disk before returning to the user.
     */
    if (mp->m_flags & XFS_MOUNT_WSYNC) {
        xfs_trans_set_sync(args.trans);
    }

    if ((flags & ATTR_KERNOTIME) == 0)
        xfs_trans_ichgtime(args.trans, dp, XFS_ICHGTIME_CHG);

    /*
     * Commit the last in the sequence of transactions.
     */
    xfs_trans_log_inode(args.trans, dp, XFS_ILOG_CORE);
    error = xfs_trans_commit(args.trans, XFS_TRANS_RELEASE_LOG_RES);
    xfs_iunlock(dp, XFS_ILOCK_EXCL);

    return(error);

out:
    if (args.trans)
        xfs_trans_cancel(args.trans,
            XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
    xfs_iunlock(dp, XFS_ILOCK_EXCL);
    return(error);
}

int
xfs_attr_set(
    xfs_inode_t *dp,
    const unsigned char *name,
    unsigned char   *value,
    int     valuelen,
    int     flags)
{
    int             error;
    struct xfs_name xname;

    XFS_STATS_INC(xs_attr_set);

    if (XFS_FORCED_SHUTDOWN(dp->i_mount))
        return (EIO);

    error = xfs_attr_name_to_xname(&xname, name);
    if (error)
        return error;

    return xfs_attr_set_int(dp, &xname, value, valuelen, flags);
}

/*
 * Generic handler routine to remove a name from an attribute list.
 * Transitions attribute list from Btree to shortform as necessary.
 */
STATIC int
xfs_attr_remove_int(xfs_inode_t *dp, struct xfs_name *name, int flags)
{
    xfs_da_args_t   args;
    xfs_fsblock_t   firstblock;
    xfs_bmap_free_t flist;
    int     error;
    xfs_mount_t *mp = dp->i_mount;

    /*
     * Fill in the arg structure for this request.
     */
    memset((char *)&args, 0, sizeof(args));
    args.name = name->name;
    args.namelen = name->len;
    args.flags = flags;
    args.hashval = xfs_da_hashname(args.name, args.namelen);
    args.dp = dp;
    args.firstblock = &firstblock;
    args.flist = &flist;
    args.total = 0;
    args.whichfork = XFS_ATTR_FORK;

    /*
     * we have no control over the attribute names that userspace passes us
     * to remove, so we have to allow the name lookup prior to attribute
     * removal to fail.
     */
    args.op_flags = XFS_DA_OP_OKNOENT;

    /*
     * Attach the dquots to the inode.
     */
    error = xfs_qm_dqattach(dp, 0);
    if (error)
        return error;

    /*
     * Start our first transaction of the day.
     *
     * All future transactions during this code must be "chained" off
     * this one via the trans_dup() call.  All transactions will contain
     * the inode, and the inode will always be marked with trans_ihold().
     * Since the inode will be locked in all transactions, we must log
     * the inode in every transaction to let it float upward through
     * the log.
     */
    args.trans = xfs_trans_alloc(mp, XFS_TRANS_ATTR_RM);

    /*
     * Root fork attributes can use reserved data blocks for this
     * operation if necessary
     */

    if (flags & ATTR_ROOT)
        args.trans->t_flags |= XFS_TRANS_RESERVE;

    if ((error = xfs_trans_reserve(args.trans,
                      XFS_ATTRRM_SPACE_RES(mp),
                      XFS_ATTRRM_LOG_RES(mp),
                      0, XFS_TRANS_PERM_LOG_RES,
                      XFS_ATTRRM_LOG_COUNT))) {
        xfs_trans_cancel(args.trans, 0);
        return(error);
    }

    xfs_ilock(dp, XFS_ILOCK_EXCL);
    /*
     * No need to make quota reservations here. We expect to release some
     * blocks not allocate in the common case.
     */
    xfs_trans_ijoin(args.trans, dp, 0);

    /*
     * Decide on what work routines to call based on the inode size.
     */
    if (!xfs_inode_hasattr(dp)) {
        error = XFS_ERROR(ENOATTR);
        goto out;
    }
    if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
        ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
        error = xfs_attr_shortform_remove(&args);
        if (error) {
            goto out;
        }
    } else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
        error = xfs_attr_leaf_removename(&args);
    } else {
        error = xfs_attr_node_removename(&args);
    }
    if (error) {
        goto out;
    }

    /*
     * If this is a synchronous mount, make sure that the
     * transaction goes to disk before returning to the user.
     */
    if (mp->m_flags & XFS_MOUNT_WSYNC) {
        xfs_trans_set_sync(args.trans);
    }

    if ((flags & ATTR_KERNOTIME) == 0)
        xfs_trans_ichgtime(args.trans, dp, XFS_ICHGTIME_CHG);

    /*
     * Commit the last in the sequence of transactions.
     */
    xfs_trans_log_inode(args.trans, dp, XFS_ILOG_CORE);
    error = xfs_trans_commit(args.trans, XFS_TRANS_RELEASE_LOG_RES);
    xfs_iunlock(dp, XFS_ILOCK_EXCL);

    return(error);

out:
    if (args.trans)
        xfs_trans_cancel(args.trans,
            XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
    xfs_iunlock(dp, XFS_ILOCK_EXCL);
    return(error);
}

int
xfs_attr_remove(
    xfs_inode_t *dp,
    const unsigned char *name,
    int     flags)
{
    int     error;
    struct xfs_name xname;

    XFS_STATS_INC(xs_attr_remove);

    if (XFS_FORCED_SHUTDOWN(dp->i_mount))
        return (EIO);

    error = xfs_attr_name_to_xname(&xname, name);
    if (error)
        return error;

    xfs_ilock(dp, XFS_ILOCK_SHARED);
    if (!xfs_inode_hasattr(dp)) {
        xfs_iunlock(dp, XFS_ILOCK_SHARED);
        return XFS_ERROR(ENOATTR);
    }
    xfs_iunlock(dp, XFS_ILOCK_SHARED);

    return xfs_attr_remove_int(dp, &xname, flags);
}

int
xfs_attr_list_int(xfs_attr_list_context_t *context)
{
    int error;
    xfs_inode_t *dp = context->dp;

    XFS_STATS_INC(xs_attr_list);

    if (XFS_FORCED_SHUTDOWN(dp->i_mount))
        return EIO;

    xfs_ilock(dp, XFS_ILOCK_SHARED);

    /*
     * Decide on what work routines to call based on the inode size.
     */
    if (!xfs_inode_hasattr(dp)) {
        error = 0;
    } else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
        error = xfs_attr_shortform_list(context);
    } else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
        error = xfs_attr_leaf_list(context);
    } else {
        error = xfs_attr_node_list(context);
    }

    xfs_iunlock(dp, XFS_ILOCK_SHARED);

    return error;
}

#define ATTR_ENTBASESIZE        /* minimum bytes used by an attr */ \
    (((struct attrlist_ent *) 0)->a_name - (char *) 0)
#define ATTR_ENTSIZE(namelen)       /* actual bytes used by an attr */ \
    ((ATTR_ENTBASESIZE + (namelen) + 1 + sizeof(u_int32_t)-1) \
     & ~(sizeof(u_int32_t)-1))

/*
 * Format an attribute and copy it out to the user's buffer.
 * Take care to check values and protect against them changing later,
 * we may be reading them directly out of a user buffer.
 */
/*ARGSUSED*/
STATIC int
xfs_attr_put_listent(
    xfs_attr_list_context_t *context,
    int     flags,
    unsigned char   *name,
    int     namelen,
    int     valuelen,
    unsigned char   *value)
{
    struct attrlist *alist = (struct attrlist *)context->alist;
    attrlist_ent_t *aep;
    int arraytop;

    ASSERT(!(context->flags & ATTR_KERNOVAL));
    ASSERT(context->count >= 0);
    ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
    ASSERT(context->firstu >= sizeof(*alist));
    ASSERT(context->firstu <= context->bufsize);

    /*
     * Only list entries in the right namespace.
     */
    if (((context->flags & ATTR_SECURE) == 0) !=
        ((flags & XFS_ATTR_SECURE) == 0))
        return 0;
    if (((context->flags & ATTR_ROOT) == 0) !=
        ((flags & XFS_ATTR_ROOT) == 0))
        return 0;

    arraytop = sizeof(*alist) +
            context->count * sizeof(alist->al_offset[0]);
    context->firstu -= ATTR_ENTSIZE(namelen);
    if (context->firstu < arraytop) {
        trace_xfs_attr_list_full(context);
        alist->al_more = 1;
        context->seen_enough = 1;
        return 1;
    }

    aep = (attrlist_ent_t *)&context->alist[context->firstu];
    aep->a_valuelen = valuelen;
    memcpy(aep->a_name, name, namelen);
    aep->a_name[namelen] = 0;
    alist->al_offset[context->count++] = context->firstu;
    alist->al_count = context->count;
    trace_xfs_attr_list_add(context);
    return 0;
}

/*
 * Generate a list of extended attribute names and optionally
 * also value lengths.  Positive return value follows the XFS
 * convention of being an error, zero or negative return code
 * is the length of the buffer returned (negated), indicating
 * success.
 */
int
xfs_attr_list(
    xfs_inode_t *dp,
    char        *buffer,
    int     bufsize,
    int     flags,
    attrlist_cursor_kern_t *cursor)
{
    xfs_attr_list_context_t context;
    struct attrlist *alist;
    int error;

    /*
     * Validate the cursor.
     */
    if (cursor->pad1 || cursor->pad2)
        return(XFS_ERROR(EINVAL));
    if ((cursor->initted == 0) &&
        (cursor->hashval || cursor->blkno || cursor->offset))
        return XFS_ERROR(EINVAL);

    /*
     * Check for a properly aligned buffer.
     */
    if (((long)buffer) & (sizeof(int)-1))
        return XFS_ERROR(EFAULT);
    if (flags & ATTR_KERNOVAL)
        bufsize = 0;

    /*
     * Initialize the output buffer.
     */
    memset(&context, 0, sizeof(context));
    context.dp = dp;
    context.cursor = cursor;
    context.resynch = 1;
    context.flags = flags;
    context.alist = buffer;
    context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
    context.firstu = context.bufsize;
    context.put_listent = xfs_attr_put_listent;

    alist = (struct attrlist *)context.alist;
    alist->al_count = 0;
    alist->al_more = 0;
    alist->al_offset[0] = context.bufsize;

    error = xfs_attr_list_int(&context);
    ASSERT(error >= 0);
    return error;
}

int                             /* error */
xfs_attr_inactive(xfs_inode_t *dp)
{
    xfs_trans_t *trans;
    xfs_mount_t *mp;
    int error;

    mp = dp->i_mount;
    ASSERT(! XFS_NOT_DQATTACHED(mp, dp));

    xfs_ilock(dp, XFS_ILOCK_SHARED);
    if (!xfs_inode_hasattr(dp) ||
        dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
        xfs_iunlock(dp, XFS_ILOCK_SHARED);
        return 0;
    }
    xfs_iunlock(dp, XFS_ILOCK_SHARED);

    /*
     * Start our first transaction of the day.
     *
     * All future transactions during this code must be "chained" off
     * this one via the trans_dup() call.  All transactions will contain
     * the inode, and the inode will always be marked with trans_ihold().
     * Since the inode will be locked in all transactions, we must log
     * the inode in every transaction to let it float upward through
     * the log.
     */
    trans = xfs_trans_alloc(mp, XFS_TRANS_ATTRINVAL);
    if ((error = xfs_trans_reserve(trans, 0, XFS_ATTRINVAL_LOG_RES(mp), 0,
                      XFS_TRANS_PERM_LOG_RES,
                      XFS_ATTRINVAL_LOG_COUNT))) {
        xfs_trans_cancel(trans, 0);
        return(error);
    }
    xfs_ilock(dp, XFS_ILOCK_EXCL);

    /*
     * No need to make quota reservations here. We expect to release some
     * blocks, not allocate, in the common case.
     */
    xfs_trans_ijoin(trans, dp, 0);

    /*
     * Decide on what work routines to call based on the inode size.
     */
    if (!xfs_inode_hasattr(dp) ||
        dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
        error = 0;
        goto out;
    }
    error = xfs_attr_root_inactive(&trans, dp);
    if (error)
        goto out;

    error = xfs_itruncate_extents(&trans, dp, XFS_ATTR_FORK, 0);
    if (error)
        goto out;

    error = xfs_trans_commit(trans, XFS_TRANS_RELEASE_LOG_RES);
    xfs_iunlock(dp, XFS_ILOCK_EXCL);

    return(error);

out:
    xfs_trans_cancel(trans, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
    xfs_iunlock(dp, XFS_ILOCK_EXCL);
    return(error);
}



/*========================================================================
 * External routines when attribute list is inside the inode
 *========================================================================*/

/*
 * Add a name to the shortform attribute list structure
 * This is the external routine.
 */
STATIC int
xfs_attr_shortform_addname(xfs_da_args_t *args)
{
    int newsize, forkoff, retval;

    trace_xfs_attr_sf_addname(args);

    retval = xfs_attr_shortform_lookup(args);
    if ((args->flags & ATTR_REPLACE) && (retval == ENOATTR)) {
        return(retval);
    } else if (retval == EEXIST) {
        if (args->flags & ATTR_CREATE)
            return(retval);
        retval = xfs_attr_shortform_remove(args);
        ASSERT(retval == 0);
    }

    if (args->namelen >= XFS_ATTR_SF_ENTSIZE_MAX ||
        args->valuelen >= XFS_ATTR_SF_ENTSIZE_MAX)
        return(XFS_ERROR(ENOSPC));

    newsize = XFS_ATTR_SF_TOTSIZE(args->dp);
    newsize += XFS_ATTR_SF_ENTSIZE_BYNAME(args->namelen, args->valuelen);

    forkoff = xfs_attr_shortform_bytesfit(args->dp, newsize);
    if (!forkoff)
        return(XFS_ERROR(ENOSPC));

    xfs_attr_shortform_add(args, forkoff);
    return(0);
}


/*========================================================================
 * External routines when attribute list is one block
 *========================================================================*/

/*
 * Add a name to the leaf attribute list structure
 *
 * This leaf block cannot have a "remote" value, we only call this routine
 * if bmap_one_block() says there is only one block (ie: no remote blks).
 */
STATIC int
xfs_attr_leaf_addname(xfs_da_args_t *args)
{
    xfs_inode_t *dp;
    struct xfs_buf *bp;
    int retval, error, committed, forkoff;

    trace_xfs_attr_leaf_addname(args);

    /*
     * Read the (only) block in the attribute list in.
     */
    dp = args->dp;
    args->blkno = 0;
    error = xfs_da_read_buf(args->trans, args->dp, args->blkno, -1, &bp,
                         XFS_ATTR_FORK);
    if (error)
        return(error);
    ASSERT(bp != NULL);

    /*
     * Look up the given attribute in the leaf block.  Figure out if
     * the given flags produce an error or call for an atomic rename.
     */
    retval = xfs_attr_leaf_lookup_int(bp, args);
    if ((args->flags & ATTR_REPLACE) && (retval == ENOATTR)) {
        xfs_trans_brelse(args->trans, bp);
        return(retval);
    } else if (retval == EEXIST) {
        if (args->flags & ATTR_CREATE) {    /* pure create op */
            xfs_trans_brelse(args->trans, bp);
            return(retval);
        }

        trace_xfs_attr_leaf_replace(args);

        args->op_flags |= XFS_DA_OP_RENAME; /* an atomic rename */
        args->blkno2 = args->blkno;     /* set 2nd entry info*/
        args->index2 = args->index;
        args->rmtblkno2 = args->rmtblkno;
        args->rmtblkcnt2 = args->rmtblkcnt;
    }

    /*
     * Add the attribute to the leaf block, transitioning to a Btree
     * if required.
     */
    retval = xfs_attr_leaf_add(bp, args);
    if (retval == ENOSPC) {
        /*
         * Promote the attribute list to the Btree format, then
         * Commit that transaction so that the node_addname() call
         * can manage its own transactions.
         */
        xfs_bmap_init(args->flist, args->firstblock);
        error = xfs_attr_leaf_to_node(args);
        if (!error) {
            error = xfs_bmap_finish(&args->trans, args->flist,
                        &committed);
        }
        if (error) {
            ASSERT(committed);
            args->trans = NULL;
            xfs_bmap_cancel(args->flist);
            return(error);
        }

        /*
         * bmap_finish() may have committed the last trans and started
         * a new one.  We need the inode to be in all transactions.
         */
        if (committed)
            xfs_trans_ijoin(args->trans, dp, 0);

        /*
         * Commit the current trans (including the inode) and start
         * a new one.
         */
        error = xfs_trans_roll(&args->trans, dp);
        if (error)
            return (error);

        /*
         * Fob the whole rest of the problem off on the Btree code.
         */
        error = xfs_attr_node_addname(args);
        return(error);
    }

    /*
     * Commit the transaction that added the attr name so that
     * later routines can manage their own transactions.
     */
    error = xfs_trans_roll(&args->trans, dp);
    if (error)
        return (error);

    /*
     * If there was an out-of-line value, allocate the blocks we
     * identified for its storage and copy the value.  This is done
     * after we create the attribute so that we don't overflow the
     * maximum size of a transaction and/or hit a deadlock.
     */
    if (args->rmtblkno > 0) {
        error = xfs_attr_rmtval_set(args);
        if (error)
            return(error);
    }

    /*
     * If this is an atomic rename operation, we must "flip" the
     * incomplete flags on the "new" and "old" attribute/value pairs
     * so that one disappears and one appears atomically.  Then we
     * must remove the "old" attribute/value pair.
     */
    if (args->op_flags & XFS_DA_OP_RENAME) {
        /*
         * In a separate transaction, set the incomplete flag on the
         * "old" attr and clear the incomplete flag on the "new" attr.
         */
        error = xfs_attr_leaf_flipflags(args);
        if (error)
            return(error);

        /*
         * Dismantle the "old" attribute/value pair by removing
         * a "remote" value (if it exists).
         */
        args->index = args->index2;
        args->blkno = args->blkno2;
        args->rmtblkno = args->rmtblkno2;
        args->rmtblkcnt = args->rmtblkcnt2;
        if (args->rmtblkno) {
            error = xfs_attr_rmtval_remove(args);
            if (error)
                return(error);
        }

        /*
         * Read in the block containing the "old" attr, then
         * remove the "old" attr from that block (neat, huh!)
         */
        error = xfs_da_read_buf(args->trans, args->dp, args->blkno, -1,
                             &bp, XFS_ATTR_FORK);
        if (error)
            return(error);
        ASSERT(bp != NULL);
        (void)xfs_attr_leaf_remove(bp, args);

        /*
         * If the result is small enough, shrink it all into the inode.
         */
        if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
            xfs_bmap_init(args->flist, args->firstblock);
            error = xfs_attr_leaf_to_shortform(bp, args, forkoff);
            /* bp is gone due to xfs_da_shrink_inode */
            if (!error) {
                error = xfs_bmap_finish(&args->trans,
                            args->flist,
                            &committed);
            }
            if (error) {
                ASSERT(committed);
                args->trans = NULL;
                xfs_bmap_cancel(args->flist);
                return(error);
            }

            /*
             * bmap_finish() may have committed the last trans
             * and started a new one.  We need the inode to be
             * in all transactions.
             */
            if (committed)
                xfs_trans_ijoin(args->trans, dp, 0);
        }

        /*
         * Commit the remove and start the next trans in series.
         */
        error = xfs_trans_roll(&args->trans, dp);

    } else if (args->rmtblkno > 0) {
        /*
         * Added a "remote" value, just clear the incomplete flag.
         */
        error = xfs_attr_leaf_clearflag(args);
    }
    return(error);
}

/*
 * Remove a name from the leaf attribute list structure
 *
 * This leaf block cannot have a "remote" value, we only call this routine
 * if bmap_one_block() says there is only one block (ie: no remote blks).
 */
STATIC int
xfs_attr_leaf_removename(xfs_da_args_t *args)
{
    xfs_inode_t *dp;
    struct xfs_buf *bp;
    int error, committed, forkoff;

    trace_xfs_attr_leaf_removename(args);

    /*
     * Remove the attribute.
     */
    dp = args->dp;
    args->blkno = 0;
    error = xfs_da_read_buf(args->trans, args->dp, args->blkno, -1, &bp,
                         XFS_ATTR_FORK);
    if (error) {
        return(error);
    }

    ASSERT(bp != NULL);
    error = xfs_attr_leaf_lookup_int(bp, args);
    if (error == ENOATTR) {
        xfs_trans_brelse(args->trans, bp);
        return(error);
    }

    (void)xfs_attr_leaf_remove(bp, args);

    /*
     * If the result is small enough, shrink it all into the inode.
     */
    if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
        xfs_bmap_init(args->flist, args->firstblock);
        error = xfs_attr_leaf_to_shortform(bp, args, forkoff);
        /* bp is gone due to xfs_da_shrink_inode */
        if (!error) {
            error = xfs_bmap_finish(&args->trans, args->flist,
                        &committed);
        }
        if (error) {
            ASSERT(committed);
            args->trans = NULL;
            xfs_bmap_cancel(args->flist);
            return(error);
        }

        /*
         * bmap_finish() may have committed the last trans and started
         * a new one.  We need the inode to be in all transactions.
         */
        if (committed)
            xfs_trans_ijoin(args->trans, dp, 0);
    }
    return(0);
}

/*
 * Look up a name in a leaf attribute list structure.
 *
 * This leaf block cannot have a "remote" value, we only call this routine
 * if bmap_one_block() says there is only one block (ie: no remote blks).
 */
STATIC int
xfs_attr_leaf_get(xfs_da_args_t *args)
{
    struct xfs_buf *bp;
    int error;

    args->blkno = 0;
    error = xfs_da_read_buf(args->trans, args->dp, args->blkno, -1, &bp,
                         XFS_ATTR_FORK);
    if (error)
        return(error);
    ASSERT(bp != NULL);

    error = xfs_attr_leaf_lookup_int(bp, args);
    if (error != EEXIST)  {
        xfs_trans_brelse(args->trans, bp);
        return(error);
    }
    error = xfs_attr_leaf_getvalue(bp, args);
    xfs_trans_brelse(args->trans, bp);
    if (!error && (args->rmtblkno > 0) && !(args->flags & ATTR_KERNOVAL)) {
        error = xfs_attr_rmtval_get(args);
    }
    return(error);
}

/*
 * Copy out attribute entries for attr_list(), for leaf attribute lists.
 */
STATIC int
xfs_attr_leaf_list(xfs_attr_list_context_t *context)
{
    xfs_attr_leafblock_t *leaf;
    int error;
    struct xfs_buf *bp;

    context->cursor->blkno = 0;
    error = xfs_da_read_buf(NULL, context->dp, 0, -1, &bp, XFS_ATTR_FORK);
    if (error)
        return XFS_ERROR(error);
    ASSERT(bp != NULL);
    leaf = bp->b_addr;
    if (unlikely(leaf->hdr.info.magic != cpu_to_be16(XFS_ATTR_LEAF_MAGIC))) {
        XFS_CORRUPTION_ERROR("xfs_attr_leaf_list", XFS_ERRLEVEL_LOW,
                     context->dp->i_mount, leaf);
        xfs_trans_brelse(NULL, bp);
        return XFS_ERROR(EFSCORRUPTED);
    }

    error = xfs_attr_leaf_list_int(bp, context);
    xfs_trans_brelse(NULL, bp);
    return XFS_ERROR(error);
}


/*========================================================================
 * External routines when attribute list size > XFS_LBSIZE(mp).
 *========================================================================*/

/*
 * Add a name to a Btree-format attribute list.
 *
 * This will involve walking down the Btree, and may involve splitting
 * leaf nodes and even splitting intermediate nodes up to and including
 * the root node (a special case of an intermediate node).
 *
 * "Remote" attribute values confuse the issue and atomic rename operations
 * add a whole extra layer of confusion on top of that.
 */
STATIC int
xfs_attr_node_addname(xfs_da_args_t *args)
{
    xfs_da_state_t *state;
    xfs_da_state_blk_t *blk;
    xfs_inode_t *dp;
    xfs_mount_t *mp;
    int committed, retval, error;

    trace_xfs_attr_node_addname(args);

    /*
     * Fill in bucket of arguments/results/context to carry around.
     */
    dp = args->dp;
    mp = dp->i_mount;
restart:
    state = xfs_da_state_alloc();
    state->args = args;
    state->mp = mp;
    state->blocksize = state->mp->m_sb.sb_blocksize;
    state->node_ents = state->mp->m_attr_node_ents;

    /*
     * Search to see if name already exists, and get back a pointer
     * to where it should go.
     */
    error = xfs_da_node_lookup_int(state, &retval);
    if (error)
        goto out;
    blk = &state->path.blk[ state->path.active-1 ];
    ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
    if ((args->flags & ATTR_REPLACE) && (retval == ENOATTR)) {
        goto out;
    } else if (retval == EEXIST) {
        if (args->flags & ATTR_CREATE)
            goto out;

        trace_xfs_attr_node_replace(args);

        args->op_flags |= XFS_DA_OP_RENAME; /* atomic rename op */
        args->blkno2 = args->blkno;     /* set 2nd entry info*/
        args->index2 = args->index;
        args->rmtblkno2 = args->rmtblkno;
        args->rmtblkcnt2 = args->rmtblkcnt;
        args->rmtblkno = 0;
        args->rmtblkcnt = 0;
    }

    retval = xfs_attr_leaf_add(blk->bp, state->args);
    if (retval == ENOSPC) {
        if (state->path.active == 1) {
            /*
             * Its really a single leaf node, but it had
             * out-of-line values so it looked like it *might*
             * have been a b-tree.
             */
            xfs_da_state_free(state);
            xfs_bmap_init(args->flist, args->firstblock);
            error = xfs_attr_leaf_to_node(args);
            if (!error) {
                error = xfs_bmap_finish(&args->trans,
                            args->flist,
                            &committed);
            }
            if (error) {
                ASSERT(committed);
                args->trans = NULL;
                xfs_bmap_cancel(args->flist);
                goto out;
            }

            /*
             * bmap_finish() may have committed the last trans
             * and started a new one.  We need the inode to be
             * in all transactions.
             */
            if (committed)
                xfs_trans_ijoin(args->trans, dp, 0);

            /*
             * Commit the node conversion and start the next
             * trans in the chain.
             */
            error = xfs_trans_roll(&args->trans, dp);
            if (error)
                goto out;

            goto restart;
        }

        /*
         * Split as many Btree elements as required.
         * This code tracks the new and old attr's location
         * in the index/blkno/rmtblkno/rmtblkcnt fields and
         * in the index2/blkno2/rmtblkno2/rmtblkcnt2 fields.
         */
        xfs_bmap_init(args->flist, args->firstblock);
        error = xfs_da_split(state);
        if (!error) {
            error = xfs_bmap_finish(&args->trans, args->flist,
                        &committed);
        }
        if (error) {
            ASSERT(committed);
            args->trans = NULL;
            xfs_bmap_cancel(args->flist);
            goto out;
        }

        /*
         * bmap_finish() may have committed the last trans and started
         * a new one.  We need the inode to be in all transactions.
         */
        if (committed)
            xfs_trans_ijoin(args->trans, dp, 0);
    } else {
        /*
         * Addition succeeded, update Btree hashvals.
         */
        xfs_da_fixhashpath(state, &state->path);
    }

    /*
     * Kill the state structure, we're done with it and need to
     * allow the buffers to come back later.
     */
    xfs_da_state_free(state);
    state = NULL;

    /*
     * Commit the leaf addition or btree split and start the next
     * trans in the chain.
     */
    error = xfs_trans_roll(&args->trans, dp);
    if (error)
        goto out;

    /*
     * If there was an out-of-line value, allocate the blocks we
     * identified for its storage and copy the value.  This is done
     * after we create the attribute so that we don't overflow the
     * maximum size of a transaction and/or hit a deadlock.
     */
    if (args->rmtblkno > 0) {
        error = xfs_attr_rmtval_set(args);
        if (error)
            return(error);
    }

    /*
     * If this is an atomic rename operation, we must "flip" the
     * incomplete flags on the "new" and "old" attribute/value pairs
     * so that one disappears and one appears atomically.  Then we
     * must remove the "old" attribute/value pair.
     */
    if (args->op_flags & XFS_DA_OP_RENAME) {
        /*
         * In a separate transaction, set the incomplete flag on the
         * "old" attr and clear the incomplete flag on the "new" attr.
         */
        error = xfs_attr_leaf_flipflags(args);
        if (error)
            goto out;

        /*
         * Dismantle the "old" attribute/value pair by removing
         * a "remote" value (if it exists).
         */
        args->index = args->index2;
        args->blkno = args->blkno2;
        args->rmtblkno = args->rmtblkno2;
        args->rmtblkcnt = args->rmtblkcnt2;
        if (args->rmtblkno) {
            error = xfs_attr_rmtval_remove(args);
            if (error)
                return(error);
        }

        /*
         * Re-find the "old" attribute entry after any split ops.
         * The INCOMPLETE flag means that we will find the "old"
         * attr, not the "new" one.
         */
        args->flags |= XFS_ATTR_INCOMPLETE;
        state = xfs_da_state_alloc();
        state->args = args;
        state->mp = mp;
        state->blocksize = state->mp->m_sb.sb_blocksize;
        state->node_ents = state->mp->m_attr_node_ents;
        state->inleaf = 0;
        error = xfs_da_node_lookup_int(state, &retval);
        if (error)
            goto out;

        /*
         * Remove the name and update the hashvals in the tree.
         */
        blk = &state->path.blk[ state->path.active-1 ];
        ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
        error = xfs_attr_leaf_remove(blk->bp, args);
        xfs_da_fixhashpath(state, &state->path);

        /*
         * Check to see if the tree needs to be collapsed.
         */
        if (retval && (state->path.active > 1)) {
            xfs_bmap_init(args->flist, args->firstblock);
            error = xfs_da_join(state);
            if (!error) {
                error = xfs_bmap_finish(&args->trans,
                            args->flist,
                            &committed);
            }
            if (error) {
                ASSERT(committed);
                args->trans = NULL;
                xfs_bmap_cancel(args->flist);
                goto out;
            }

            /*
             * bmap_finish() may have committed the last trans
             * and started a new one.  We need the inode to be
             * in all transactions.
             */
            if (committed)
                xfs_trans_ijoin(args->trans, dp, 0);
        }

        /*
         * Commit and start the next trans in the chain.
         */
        error = xfs_trans_roll(&args->trans, dp);
        if (error)
            goto out;

    } else if (args->rmtblkno > 0) {
        /*
         * Added a "remote" value, just clear the incomplete flag.
         */
        error = xfs_attr_leaf_clearflag(args);
        if (error)
            goto out;
    }
    retval = error = 0;

out:
    if (state)
        xfs_da_state_free(state);
    if (error)
        return(error);
    return(retval);
}

/*
 * Remove a name from a B-tree attribute list.
 *
 * This will involve walking down the Btree, and may involve joining
 * leaf nodes and even joining intermediate nodes up to and including
 * the root node (a special case of an intermediate node).
 */
STATIC int
xfs_attr_node_removename(xfs_da_args_t *args)
{
    xfs_da_state_t *state;
    xfs_da_state_blk_t *blk;
    xfs_inode_t *dp;
    struct xfs_buf *bp;
    int retval, error, committed, forkoff;

    trace_xfs_attr_node_removename(args);

    /*
     * Tie a string around our finger to remind us where we are.
     */
    dp = args->dp;
    state = xfs_da_state_alloc();
    state->args = args;
    state->mp = dp->i_mount;
    state->blocksize = state->mp->m_sb.sb_blocksize;
    state->node_ents = state->mp->m_attr_node_ents;

    /*
     * Search to see if name exists, and get back a pointer to it.
     */
    error = xfs_da_node_lookup_int(state, &retval);
    if (error || (retval != EEXIST)) {
        if (error == 0)
            error = retval;
        goto out;
    }

    /*
     * If there is an out-of-line value, de-allocate the blocks.
     * This is done before we remove the attribute so that we don't
     * overflow the maximum size of a transaction and/or hit a deadlock.
     */
    blk = &state->path.blk[ state->path.active-1 ];
    ASSERT(blk->bp != NULL);
    ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
    if (args->rmtblkno > 0) {
        /*
         * Fill in disk block numbers in the state structure
         * so that we can get the buffers back after we commit
         * several transactions in the following calls.
         */
        error = xfs_attr_fillstate(state);
        if (error)
            goto out;

        /*
         * Mark the attribute as INCOMPLETE, then bunmapi() the
         * remote value.
         */
        error = xfs_attr_leaf_setflag(args);
        if (error)
            goto out;
        error = xfs_attr_rmtval_remove(args);
        if (error)
            goto out;

        /*
         * Refill the state structure with buffers, the prior calls
         * released our buffers.
         */
        error = xfs_attr_refillstate(state);
        if (error)
            goto out;
    }

    /*
     * Remove the name and update the hashvals in the tree.
     */
    blk = &state->path.blk[ state->path.active-1 ];
    ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
    retval = xfs_attr_leaf_remove(blk->bp, args);
    xfs_da_fixhashpath(state, &state->path);

    /*
     * Check to see if the tree needs to be collapsed.
     */
    if (retval && (state->path.active > 1)) {
        xfs_bmap_init(args->flist, args->firstblock);
        error = xfs_da_join(state);
        if (!error) {
            error = xfs_bmap_finish(&args->trans, args->flist,
                        &committed);
        }
        if (error) {
            ASSERT(committed);
            args->trans = NULL;
            xfs_bmap_cancel(args->flist);
            goto out;
        }

        /*
         * bmap_finish() may have committed the last trans and started
         * a new one.  We need the inode to be in all transactions.
         */
        if (committed)
            xfs_trans_ijoin(args->trans, dp, 0);

        /*
         * Commit the Btree join operation and start a new trans.
         */
        error = xfs_trans_roll(&args->trans, dp);
        if (error)
            goto out;
    }

    /*
     * If the result is small enough, push it all into the inode.
     */
    if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
        /*
         * Have to get rid of the copy of this dabuf in the state.
         */
        ASSERT(state->path.active == 1);
        ASSERT(state->path.blk[0].bp);
        state->path.blk[0].bp = NULL;

        error = xfs_da_read_buf(args->trans, args->dp, 0, -1, &bp,
                             XFS_ATTR_FORK);
        if (error)
            goto out;
        ASSERT((((xfs_attr_leafblock_t *)bp->b_addr)->hdr.info.magic) ==
               cpu_to_be16(XFS_ATTR_LEAF_MAGIC));

        if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
            xfs_bmap_init(args->flist, args->firstblock);
            error = xfs_attr_leaf_to_shortform(bp, args, forkoff);
            /* bp is gone due to xfs_da_shrink_inode */
            if (!error) {
                error = xfs_bmap_finish(&args->trans,
                            args->flist,
                            &committed);
            }
            if (error) {
                ASSERT(committed);
                args->trans = NULL;
                xfs_bmap_cancel(args->flist);
                goto out;
            }

            /*
             * bmap_finish() may have committed the last trans
             * and started a new one.  We need the inode to be
             * in all transactions.
             */
            if (committed)
                xfs_trans_ijoin(args->trans, dp, 0);
        } else
            xfs_trans_brelse(args->trans, bp);
    }
    error = 0;

out:
    xfs_da_state_free(state);
    return(error);
}

/*
 * Fill in the disk block numbers in the state structure for the buffers
 * that are attached to the state structure.
 * This is done so that we can quickly reattach ourselves to those buffers
 * after some set of transaction commits have released these buffers.
 */
STATIC int
xfs_attr_fillstate(xfs_da_state_t *state)
{
    xfs_da_state_path_t *path;
    xfs_da_state_blk_t *blk;
    int level;

    /*
     * Roll down the "path" in the state structure, storing the on-disk
     * block number for those buffers in the "path".
     */
    path = &state->path;
    ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
    for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
        if (blk->bp) {
            blk->disk_blkno = XFS_BUF_ADDR(blk->bp);
            blk->bp = NULL;
        } else {
            blk->disk_blkno = 0;
        }
    }

    /*
     * Roll down the "altpath" in the state structure, storing the on-disk
     * block number for those buffers in the "altpath".
     */
    path = &state->altpath;
    ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
    for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
        if (blk->bp) {
            blk->disk_blkno = XFS_BUF_ADDR(blk->bp);
            blk->bp = NULL;
        } else {
            blk->disk_blkno = 0;
        }
    }

    return(0);
}

/*
 * Reattach the buffers to the state structure based on the disk block
 * numbers stored in the state structure.
 * This is done after some set of transaction commits have released those
 * buffers from our grip.
 */
STATIC int
xfs_attr_refillstate(xfs_da_state_t *state)
{
    xfs_da_state_path_t *path;
    xfs_da_state_blk_t *blk;
    int level, error;

    /*
     * Roll down the "path" in the state structure, storing the on-disk
     * block number for those buffers in the "path".
     */
    path = &state->path;
    ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
    for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
        if (blk->disk_blkno) {
            error = xfs_da_read_buf(state->args->trans,
                        state->args->dp,
                        blk->blkno, blk->disk_blkno,
                        &blk->bp, XFS_ATTR_FORK);
            if (error)
                return(error);
        } else {
            blk->bp = NULL;
        }
    }

    /*
     * Roll down the "altpath" in the state structure, storing the on-disk
     * block number for those buffers in the "altpath".
     */
    path = &state->altpath;
    ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
    for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
        if (blk->disk_blkno) {
            error = xfs_da_read_buf(state->args->trans,
                        state->args->dp,
                        blk->blkno, blk->disk_blkno,
                        &blk->bp, XFS_ATTR_FORK);
            if (error)
                return(error);
        } else {
            blk->bp = NULL;
        }
    }

    return(0);
}

/*
 * Look up a filename in a node attribute list.
 *
 * This routine gets called for any attribute fork that has more than one
 * block, ie: both true Btree attr lists and for single-leaf-blocks with
 * "remote" values taking up more blocks.
 */
STATIC int
xfs_attr_node_get(xfs_da_args_t *args)
{
    xfs_da_state_t *state;
    xfs_da_state_blk_t *blk;
    int error, retval;
    int i;

    state = xfs_da_state_alloc();
    state->args = args;
    state->mp = args->dp->i_mount;
    state->blocksize = state->mp->m_sb.sb_blocksize;
    state->node_ents = state->mp->m_attr_node_ents;

    /*
     * Search to see if name exists, and get back a pointer to it.
     */
    error = xfs_da_node_lookup_int(state, &retval);
    if (error) {
        retval = error;
    } else if (retval == EEXIST) {
        blk = &state->path.blk[ state->path.active-1 ];
        ASSERT(blk->bp != NULL);
        ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);

        /*
         * Get the value, local or "remote"
         */
        retval = xfs_attr_leaf_getvalue(blk->bp, args);
        if (!retval && (args->rmtblkno > 0)
            && !(args->flags & ATTR_KERNOVAL)) {
            retval = xfs_attr_rmtval_get(args);
        }
    }

    /*
     * If not in a transaction, we have to release all the buffers.
     */
    for (i = 0; i < state->path.active; i++) {
        xfs_trans_brelse(args->trans, state->path.blk[i].bp);
        state->path.blk[i].bp = NULL;
    }

    xfs_da_state_free(state);
    return(retval);
}

STATIC int                          /* error */
xfs_attr_node_list(xfs_attr_list_context_t *context)
{
    attrlist_cursor_kern_t *cursor;
    xfs_attr_leafblock_t *leaf;
    xfs_da_intnode_t *node;
    xfs_da_node_entry_t *btree;
    int error, i;
    struct xfs_buf *bp;

    cursor = context->cursor;
    cursor->initted = 1;

    /*
     * Do all sorts of validation on the passed-in cursor structure.
     * If anything is amiss, ignore the cursor and look up the hashval
     * starting from the btree root.
     */
    bp = NULL;
    if (cursor->blkno > 0) {
        error = xfs_da_read_buf(NULL, context->dp, cursor->blkno, -1,
                          &bp, XFS_ATTR_FORK);
        if ((error != 0) && (error != EFSCORRUPTED))
            return(error);
        if (bp) {
            node = bp->b_addr;
            switch (be16_to_cpu(node->hdr.info.magic)) {
            case XFS_DA_NODE_MAGIC:
                trace_xfs_attr_list_wrong_blk(context);
                xfs_trans_brelse(NULL, bp);
                bp = NULL;
                break;
            case XFS_ATTR_LEAF_MAGIC:
                leaf = bp->b_addr;
                if (cursor->hashval > be32_to_cpu(leaf->entries[
                    be16_to_cpu(leaf->hdr.count)-1].hashval)) {
                    trace_xfs_attr_list_wrong_blk(context);
                    xfs_trans_brelse(NULL, bp);
                    bp = NULL;
                } else if (cursor->hashval <=
                         be32_to_cpu(leaf->entries[0].hashval)) {
                    trace_xfs_attr_list_wrong_blk(context);
                    xfs_trans_brelse(NULL, bp);
                    bp = NULL;
                }
                break;
            default:
                trace_xfs_attr_list_wrong_blk(context);
                xfs_trans_brelse(NULL, bp);
                bp = NULL;
            }
        }
    }

    /*
     * We did not find what we expected given the cursor's contents,
     * so we start from the top and work down based on the hash value.
     * Note that start of node block is same as start of leaf block.
     */
    if (bp == NULL) {
        cursor->blkno = 0;
        for (;;) {
            error = xfs_da_read_buf(NULL, context->dp,
                              cursor->blkno, -1, &bp,
                              XFS_ATTR_FORK);
            if (error)
                return(error);
            if (unlikely(bp == NULL)) {
                XFS_ERROR_REPORT("xfs_attr_node_list(2)",
                         XFS_ERRLEVEL_LOW,
                         context->dp->i_mount);
                return(XFS_ERROR(EFSCORRUPTED));
            }
            node = bp->b_addr;
            if (node->hdr.info.magic ==
                cpu_to_be16(XFS_ATTR_LEAF_MAGIC))
                break;
            if (unlikely(node->hdr.info.magic !=
                     cpu_to_be16(XFS_DA_NODE_MAGIC))) {
                XFS_CORRUPTION_ERROR("xfs_attr_node_list(3)",
                             XFS_ERRLEVEL_LOW,
                             context->dp->i_mount,
                             node);
                xfs_trans_brelse(NULL, bp);
                return(XFS_ERROR(EFSCORRUPTED));
            }
            btree = node->btree;
            for (i = 0; i < be16_to_cpu(node->hdr.count);
                                btree++, i++) {
                if (cursor->hashval
                        <= be32_to_cpu(btree->hashval)) {
                    cursor->blkno = be32_to_cpu(btree->before);
                    trace_xfs_attr_list_node_descend(context,
                                     btree);
                    break;
                }
            }
            if (i == be16_to_cpu(node->hdr.count)) {
                xfs_trans_brelse(NULL, bp);
                return(0);
            }
            xfs_trans_brelse(NULL, bp);
        }
    }
    ASSERT(bp != NULL);

    /*
     * Roll upward through the blocks, processing each leaf block in
     * order.  As long as there is space in the result buffer, keep
     * adding the information.
     */
    for (;;) {
        leaf = bp->b_addr;
        if (unlikely(leaf->hdr.info.magic !=
                 cpu_to_be16(XFS_ATTR_LEAF_MAGIC))) {
            XFS_CORRUPTION_ERROR("xfs_attr_node_list(4)",
                         XFS_ERRLEVEL_LOW,
                         context->dp->i_mount, leaf);
            xfs_trans_brelse(NULL, bp);
            return(XFS_ERROR(EFSCORRUPTED));
        }
        error = xfs_attr_leaf_list_int(bp, context);
        if (error) {
            xfs_trans_brelse(NULL, bp);
            return error;
        }
        if (context->seen_enough || leaf->hdr.info.forw == 0)
            break;
        cursor->blkno = be32_to_cpu(leaf->hdr.info.forw);
        xfs_trans_brelse(NULL, bp);
        error = xfs_da_read_buf(NULL, context->dp, cursor->blkno, -1,
                          &bp, XFS_ATTR_FORK);
        if (error)
            return(error);
        if (unlikely((bp == NULL))) {
            XFS_ERROR_REPORT("xfs_attr_node_list(5)",
                     XFS_ERRLEVEL_LOW,
                     context->dp->i_mount);
            return(XFS_ERROR(EFSCORRUPTED));
        }
    }
    xfs_trans_brelse(NULL, bp);
    return(0);
}


/*========================================================================
 * External routines for manipulating out-of-line attribute values.
 *========================================================================*/

/*
 * Read the value associated with an attribute from the out-of-line buffer
 * that we stored it in.
 */
int
xfs_attr_rmtval_get(xfs_da_args_t *args)
{
    xfs_bmbt_irec_t map[ATTR_RMTVALUE_MAPSIZE];
    xfs_mount_t *mp;
    xfs_daddr_t dblkno;
    void *dst;
    xfs_buf_t *bp;
    int nmap, error, tmp, valuelen, blkcnt, i;
    xfs_dablk_t lblkno;

    ASSERT(!(args->flags & ATTR_KERNOVAL));

    mp = args->dp->i_mount;
    dst = args->value;
    valuelen = args->valuelen;
    lblkno = args->rmtblkno;
    while (valuelen > 0) {
        nmap = ATTR_RMTVALUE_MAPSIZE;
        error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
                       args->rmtblkcnt, map, &nmap,
                       XFS_BMAPI_ATTRFORK);
        if (error)
            return(error);
        ASSERT(nmap >= 1);

        for (i = 0; (i < nmap) && (valuelen > 0); i++) {
            ASSERT((map[i].br_startblock != DELAYSTARTBLOCK) &&
                   (map[i].br_startblock != HOLESTARTBLOCK));
            dblkno = XFS_FSB_TO_DADDR(mp, map[i].br_startblock);
            blkcnt = XFS_FSB_TO_BB(mp, map[i].br_blockcount);
            error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
                           dblkno, blkcnt, 0, &bp);
            if (error)
                return(error);

            tmp = min_t(int, valuelen, BBTOB(bp->b_length));
            xfs_buf_iomove(bp, 0, tmp, dst, XBRW_READ);
            xfs_buf_relse(bp);
            dst += tmp;
            valuelen -= tmp;

            lblkno += map[i].br_blockcount;
        }
    }
    ASSERT(valuelen == 0);
    return(0);
}

/*
 * Write the value associated with an attribute into the out-of-line buffer
 * that we have defined for it.
 */
STATIC int
xfs_attr_rmtval_set(xfs_da_args_t *args)
{
    xfs_mount_t *mp;
    xfs_fileoff_t lfileoff;
    xfs_inode_t *dp;
    xfs_bmbt_irec_t map;
    xfs_daddr_t dblkno;
    void *src;
    xfs_buf_t *bp;
    xfs_dablk_t lblkno;
    int blkcnt, valuelen, nmap, error, tmp, committed;

    dp = args->dp;
    mp = dp->i_mount;
    src = args->value;

    /*
     * Find a "hole" in the attribute address space large enough for
     * us to drop the new attribute's value into.
     */
    blkcnt = XFS_B_TO_FSB(mp, args->valuelen);
    lfileoff = 0;
    error = xfs_bmap_first_unused(args->trans, args->dp, blkcnt, &lfileoff,
                           XFS_ATTR_FORK);
    if (error) {
        return(error);
    }
    args->rmtblkno = lblkno = (xfs_dablk_t)lfileoff;
    args->rmtblkcnt = blkcnt;

    /*
     * Roll through the "value", allocating blocks on disk as required.
     */
    while (blkcnt > 0) {
        /*
         * Allocate a single extent, up to the size of the value.
         */
        xfs_bmap_init(args->flist, args->firstblock);
        nmap = 1;
        error = xfs_bmapi_write(args->trans, dp, (xfs_fileoff_t)lblkno,
                  blkcnt,
                  XFS_BMAPI_ATTRFORK | XFS_BMAPI_METADATA,
                  args->firstblock, args->total, &map, &nmap,
                  args->flist);
        if (!error) {
            error = xfs_bmap_finish(&args->trans, args->flist,
                        &committed);
        }
        if (error) {
            ASSERT(committed);
            args->trans = NULL;
            xfs_bmap_cancel(args->flist);
            return(error);
        }

        /*
         * bmap_finish() may have committed the last trans and started
         * a new one.  We need the inode to be in all transactions.
         */
        if (committed)
            xfs_trans_ijoin(args->trans, dp, 0);

        ASSERT(nmap == 1);
        ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
               (map.br_startblock != HOLESTARTBLOCK));
        lblkno += map.br_blockcount;
        blkcnt -= map.br_blockcount;

        /*
         * Start the next trans in the chain.
         */
        error = xfs_trans_roll(&args->trans, dp);
        if (error)
            return (error);
    }

    /*
     * Roll through the "value", copying the attribute value to the
     * already-allocated blocks.  Blocks are written synchronously
     * so that we can know they are all on disk before we turn off
     * the INCOMPLETE flag.
     */
    lblkno = args->rmtblkno;
    valuelen = args->valuelen;
    while (valuelen > 0) {
        int buflen;

        /*
         * Try to remember where we decided to put the value.
         */
        xfs_bmap_init(args->flist, args->firstblock);
        nmap = 1;
        error = xfs_bmapi_read(dp, (xfs_fileoff_t)lblkno,
                       args->rmtblkcnt, &map, &nmap,
                       XFS_BMAPI_ATTRFORK);
        if (error)
            return(error);
        ASSERT(nmap == 1);
        ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
               (map.br_startblock != HOLESTARTBLOCK));

        dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
        blkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);

        bp = xfs_buf_get(mp->m_ddev_targp, dblkno, blkcnt, 0);
        if (!bp)
            return ENOMEM;

        buflen = BBTOB(bp->b_length);
        tmp = min_t(int, valuelen, buflen);
        xfs_buf_iomove(bp, 0, tmp, src, XBRW_WRITE);
        if (tmp < buflen)
            xfs_buf_zero(bp, tmp, buflen - tmp);

        error = xfs_bwrite(bp); /* GROT: NOTE: synchronous write */
        xfs_buf_relse(bp);
        if (error)
            return error;
        src += tmp;
        valuelen -= tmp;

        lblkno += map.br_blockcount;
    }
    ASSERT(valuelen == 0);
    return(0);
}

/*
 * Remove the value associated with an attribute by deleting the
 * out-of-line buffer that it is stored on.
 */
STATIC int
xfs_attr_rmtval_remove(xfs_da_args_t *args)
{
    xfs_mount_t *mp;
    xfs_bmbt_irec_t map;
    xfs_buf_t *bp;
    xfs_daddr_t dblkno;
    xfs_dablk_t lblkno;
    int valuelen, blkcnt, nmap, error, done, committed;

    mp = args->dp->i_mount;

    /*
     * Roll through the "value", invalidating the attribute value's
     * blocks.
     */
    lblkno = args->rmtblkno;
    valuelen = args->rmtblkcnt;
    while (valuelen > 0) {
        /*
         * Try to remember where we decided to put the value.
         */
        nmap = 1;
        error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
                       args->rmtblkcnt, &map, &nmap,
                       XFS_BMAPI_ATTRFORK);
        if (error)
            return(error);
        ASSERT(nmap == 1);
        ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
               (map.br_startblock != HOLESTARTBLOCK));

        dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
        blkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);

        /*
         * If the "remote" value is in the cache, remove it.
         */
        bp = xfs_incore(mp->m_ddev_targp, dblkno, blkcnt, XBF_TRYLOCK);
        if (bp) {
            xfs_buf_stale(bp);
            xfs_buf_relse(bp);
            bp = NULL;
        }

        valuelen -= map.br_blockcount;

        lblkno += map.br_blockcount;
    }

    /*
     * Keep de-allocating extents until the remote-value region is gone.
     */
    lblkno = args->rmtblkno;
    blkcnt = args->rmtblkcnt;
    done = 0;
    while (!done) {
        xfs_bmap_init(args->flist, args->firstblock);
        error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
                    XFS_BMAPI_ATTRFORK | XFS_BMAPI_METADATA,
                    1, args->firstblock, args->flist,
                    &done);
        if (!error) {
            error = xfs_bmap_finish(&args->trans, args->flist,
                        &committed);
        }
        if (error) {
            ASSERT(committed);
            args->trans = NULL;
            xfs_bmap_cancel(args->flist);
            return(error);
        }

        /*
         * bmap_finish() may have committed the last trans and started
         * a new one.  We need the inode to be in all transactions.
         */
        if (committed)
            xfs_trans_ijoin(args->trans, args->dp, 0);

        /*
         * Close out trans and start the next one in the chain.
         */
        error = xfs_trans_roll(&args->trans, args->dp);
        if (error)
            return (error);
    }
    return(0);
}