// SPDX-License-Identifier: GPL-2.0-only
/*
 * xattr.c
 *
 * Copyright (C) 2004, 2008 Oracle.  All rights reserved.
 *
 * CREDITS:
 * Lots of code in this file is copy from linux/fs/ext3/xattr.c.
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 */

#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/uio.h>
#include <linux/sched.h>
#include <linux/splice.h>
#include <linux/mount.h>
#include <linux/writeback.h>
#include <linux/falloc.h>
#include <linux/sort.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/security.h>

#include <cluster/masklog.h>

#include "ocfs2.h"
#include "alloc.h"
#include "blockcheck.h"
#include "dlmglue.h"
#include "file.h"
#include "symlink.h"
#include "sysfile.h"
#include "inode.h"
#include "journal.h"
#include "ocfs2_fs.h"
#include "suballoc.h"
#include "uptodate.h"
#include "buffer_head_io.h"
#include "super.h"
#include "xattr.h"
#include "refcounttree.h"
#include "acl.h"
#include "ocfs2_trace.h"

struct ocfs2_xattr_def_value_root {
        struct ocfs2_xattr_value_root   xv;
        struct ocfs2_extent_rec         er;
};

struct ocfs2_xattr_bucket {
        /* The inode these xattrs are associated with */
        struct inode *bu_inode;

        /* The actual buffers that make up the bucket */
        struct buffer_head *bu_bhs[OCFS2_XATTR_MAX_BLOCKS_PER_BUCKET];

        /* How many blocks make up one bucket for this filesystem */
        int bu_blocks;
};

struct ocfs2_xattr_set_ctxt {
        handle_t *handle;
        struct ocfs2_alloc_context *meta_ac;
        struct ocfs2_alloc_context *data_ac;
        struct ocfs2_cached_dealloc_ctxt dealloc;
        int set_abort;
};

#define OCFS2_XATTR_ROOT_SIZE   (sizeof(struct ocfs2_xattr_def_value_root))
#define OCFS2_XATTR_INLINE_SIZE 80
#define OCFS2_XATTR_HEADER_GAP  4
#define OCFS2_XATTR_FREE_IN_IBODY       (OCFS2_MIN_XATTR_INLINE_SIZE \
                                         - sizeof(struct ocfs2_xattr_header) \
                                         - OCFS2_XATTR_HEADER_GAP)
#define OCFS2_XATTR_FREE_IN_BLOCK(ptr)  ((ptr)->i_sb->s_blocksize \
                                         - sizeof(struct ocfs2_xattr_block) \
                                         - sizeof(struct ocfs2_xattr_header) \
                                         - OCFS2_XATTR_HEADER_GAP)

static struct ocfs2_xattr_def_value_root def_xv = {
        .xv.xr_list.l_count = cpu_to_le16(1),
};

const struct xattr_handler *ocfs2_xattr_handlers[] = {
        &ocfs2_xattr_user_handler,
        &posix_acl_access_xattr_handler,
        &posix_acl_default_xattr_handler,
        &ocfs2_xattr_trusted_handler,
        &ocfs2_xattr_security_handler,
        NULL
};

static const struct xattr_handler *ocfs2_xattr_handler_map[OCFS2_XATTR_MAX] = {
        [OCFS2_XATTR_INDEX_USER]        = &ocfs2_xattr_user_handler,
        [OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS]
                                        = &posix_acl_access_xattr_handler,
        [OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT]
                                        = &posix_acl_default_xattr_handler,
        [OCFS2_XATTR_INDEX_TRUSTED]     = &ocfs2_xattr_trusted_handler,
        [OCFS2_XATTR_INDEX_SECURITY]    = &ocfs2_xattr_security_handler,
};

struct ocfs2_xattr_info {
        int             xi_name_index;
        const char      *xi_name;
        int             xi_name_len;
        const void      *xi_value;
        size_t          xi_value_len;
};

struct ocfs2_xattr_search {
        struct buffer_head *inode_bh;
        /*
         * xattr_bh point to the block buffer head which has extended attribute
         * when extended attribute in inode, xattr_bh is equal to inode_bh.
         */
        struct buffer_head *xattr_bh;
        struct ocfs2_xattr_header *header;
        struct ocfs2_xattr_bucket *bucket;
        void *base;
        void *end;
        struct ocfs2_xattr_entry *here;
        int not_found;
};

/* Operations on struct ocfs2_xa_entry */
struct ocfs2_xa_loc;
struct ocfs2_xa_loc_operations {
        /*
         * Journal functions
         */
        int (*xlo_journal_access)(handle_t *handle, struct ocfs2_xa_loc *loc,
                                  int type);
        void (*xlo_journal_dirty)(handle_t *handle, struct ocfs2_xa_loc *loc);

        /*
         * Return a pointer to the appropriate buffer in loc->xl_storage
         * at the given offset from loc->xl_header.
         */
        void *(*xlo_offset_pointer)(struct ocfs2_xa_loc *loc, int offset);

        /* Can we reuse the existing entry for the new value? */
        int (*xlo_can_reuse)(struct ocfs2_xa_loc *loc,
                             struct ocfs2_xattr_info *xi);

        /* How much space is needed for the new value? */
        int (*xlo_check_space)(struct ocfs2_xa_loc *loc,
                               struct ocfs2_xattr_info *xi);

        /*
         * Return the offset of the first name+value pair.  This is
         * the start of our downward-filling free space.
         */
        int (*xlo_get_free_start)(struct ocfs2_xa_loc *loc);

        /*
         * Remove the name+value at this location.  Do whatever is
         * appropriate with the remaining name+value pairs.
         */
        void (*xlo_wipe_namevalue)(struct ocfs2_xa_loc *loc);

        /* Fill xl_entry with a new entry */
        void (*xlo_add_entry)(struct ocfs2_xa_loc *loc, u32 name_hash);

        /* Add name+value storage to an entry */
        void (*xlo_add_namevalue)(struct ocfs2_xa_loc *loc, int size);

        /*
         * Initialize the value buf's access and bh fields for this entry.
         * ocfs2_xa_fill_value_buf() will handle the xv pointer.
         */
        void (*xlo_fill_value_buf)(struct ocfs2_xa_loc *loc,
                                   struct ocfs2_xattr_value_buf *vb);
};

/*
 * Describes an xattr entry location.  This is a memory structure
 * tracking the on-disk structure.
 */
struct ocfs2_xa_loc {
        /* This xattr belongs to this inode */
        struct inode *xl_inode;

        /* The ocfs2_xattr_header inside the on-disk storage. Not NULL. */
        struct ocfs2_xattr_header *xl_header;

        /* Bytes from xl_header to the end of the storage */
        int xl_size;

        /*
         * The ocfs2_xattr_entry this location describes.  If this is
         * NULL, this location describes the on-disk structure where it
         * would have been.
         */
        struct ocfs2_xattr_entry *xl_entry;

        /*
         * Internal housekeeping
         */

        /* Buffer(s) containing this entry */
        void *xl_storage;

        /* Operations on the storage backing this location */
        const struct ocfs2_xa_loc_operations *xl_ops;
};

/*
 * Convenience functions to calculate how much space is needed for a
 * given name+value pair
 */
static int namevalue_size(int name_len, uint64_t value_len)
{
        if (value_len > OCFS2_XATTR_INLINE_SIZE)
                return OCFS2_XATTR_SIZE(name_len) + OCFS2_XATTR_ROOT_SIZE;
        else
                return OCFS2_XATTR_SIZE(name_len) + OCFS2_XATTR_SIZE(value_len);
}

static int namevalue_size_xi(struct ocfs2_xattr_info *xi)
{
        return namevalue_size(xi->xi_name_len, xi->xi_value_len);
}

static int namevalue_size_xe(struct ocfs2_xattr_entry *xe)
{
        u64 value_len = le64_to_cpu(xe->xe_value_size);

        BUG_ON((value_len > OCFS2_XATTR_INLINE_SIZE) &&
               ocfs2_xattr_is_local(xe));
        return namevalue_size(xe->xe_name_len, value_len);
}


static int ocfs2_xattr_bucket_get_name_value(struct super_block *sb,
                                             struct ocfs2_xattr_header *xh,
                                             int index,
                                             int *block_off,
                                             int *new_offset);

static int ocfs2_xattr_block_find(struct inode *inode,
                                  int name_index,
                                  const char *name,
                                  struct ocfs2_xattr_search *xs);
static int ocfs2_xattr_index_block_find(struct inode *inode,
                                        struct buffer_head *root_bh,
                                        int name_index,
                                        const char *name,
                                        struct ocfs2_xattr_search *xs);

static int ocfs2_xattr_tree_list_index_block(struct inode *inode,
                                        struct buffer_head *blk_bh,
                                        char *buffer,
                                        size_t buffer_size);

static int ocfs2_xattr_create_index_block(struct inode *inode,
                                          struct ocfs2_xattr_search *xs,
                                          struct ocfs2_xattr_set_ctxt *ctxt);

static int ocfs2_xattr_set_entry_index_block(struct inode *inode,
                                             struct ocfs2_xattr_info *xi,
                                             struct ocfs2_xattr_search *xs,
                                             struct ocfs2_xattr_set_ctxt *ctxt);

typedef int (xattr_tree_rec_func)(struct inode *inode,
                                  struct buffer_head *root_bh,
                                  u64 blkno, u32 cpos, u32 len, void *para);
static int ocfs2_iterate_xattr_index_block(struct inode *inode,
                                           struct buffer_head *root_bh,
                                           xattr_tree_rec_func *rec_func,
                                           void *para);
static int ocfs2_delete_xattr_in_bucket(struct inode *inode,
                                        struct ocfs2_xattr_bucket *bucket,
                                        void *para);
static int ocfs2_rm_xattr_cluster(struct inode *inode,
                                  struct buffer_head *root_bh,
                                  u64 blkno,
                                  u32 cpos,
                                  u32 len,
                                  void *para);

static int ocfs2_mv_xattr_buckets(struct inode *inode, handle_t *handle,
                                  u64 src_blk, u64 last_blk, u64 to_blk,
                                  unsigned int start_bucket,
                                  u32 *first_hash);
static int ocfs2_prepare_refcount_xattr(struct inode *inode,
                                        struct ocfs2_dinode *di,
                                        struct ocfs2_xattr_info *xi,
                                        struct ocfs2_xattr_search *xis,
                                        struct ocfs2_xattr_search *xbs,
                                        struct ocfs2_refcount_tree **ref_tree,
                                        int *meta_need,
                                        int *credits);
static int ocfs2_get_xattr_tree_value_root(struct super_block *sb,
                                           struct ocfs2_xattr_bucket *bucket,
                                           int offset,
                                           struct ocfs2_xattr_value_root **xv,
                                           struct buffer_head **bh);

static inline u16 ocfs2_xattr_buckets_per_cluster(struct ocfs2_super *osb)
{
        return (1 << osb->s_clustersize_bits) / OCFS2_XATTR_BUCKET_SIZE;
}

static inline u16 ocfs2_blocks_per_xattr_bucket(struct super_block *sb)
{
        return OCFS2_XATTR_BUCKET_SIZE / (1 << sb->s_blocksize_bits);
}

#define bucket_blkno(_b) ((_b)->bu_bhs[0]->b_blocknr)
#define bucket_block(_b, _n) ((_b)->bu_bhs[(_n)]->b_data)
#define bucket_xh(_b) ((struct ocfs2_xattr_header *)bucket_block((_b), 0))

static struct ocfs2_xattr_bucket *ocfs2_xattr_bucket_new(struct inode *inode)
{
        struct ocfs2_xattr_bucket *bucket;
        int blks = ocfs2_blocks_per_xattr_bucket(inode->i_sb);

        BUG_ON(blks > OCFS2_XATTR_MAX_BLOCKS_PER_BUCKET);

        bucket = kzalloc(sizeof(struct ocfs2_xattr_bucket), GFP_NOFS);
        if (bucket) {
                bucket->bu_inode = inode;
                bucket->bu_blocks = blks;
        }

        return bucket;
}

static void ocfs2_xattr_bucket_relse(struct ocfs2_xattr_bucket *bucket)
{
        int i;

        for (i = 0; i < bucket->bu_blocks; i++) {
                brelse(bucket->bu_bhs[i]);
                bucket->bu_bhs[i] = NULL;
        }
}

static void ocfs2_xattr_bucket_free(struct ocfs2_xattr_bucket *bucket)
{
        if (bucket) {
                ocfs2_xattr_bucket_relse(bucket);
                bucket->bu_inode = NULL;
                kfree(bucket);
        }
}

/*
 * A bucket that has never been written to disk doesn't need to be
 * read.  We just need the buffer_heads.  Don't call this for
 * buckets that are already on disk.  ocfs2_read_xattr_bucket() initializes
 * them fully.
 */
static int ocfs2_init_xattr_bucket(struct ocfs2_xattr_bucket *bucket,
                                   u64 xb_blkno, int new)
{
        int i, rc = 0;

        for (i = 0; i < bucket->bu_blocks; i++) {
                bucket->bu_bhs[i] = sb_getblk(bucket->bu_inode->i_sb,
                                              xb_blkno + i);
                if (!bucket->bu_bhs[i]) {
                        rc = -ENOMEM;
                        mlog_errno(rc);
                        break;
                }

                if (!ocfs2_buffer_uptodate(INODE_CACHE(bucket->bu_inode),
                                           bucket->bu_bhs[i])) {
                        if (new)
                                ocfs2_set_new_buffer_uptodate(INODE_CACHE(bucket->bu_inode),
                                                              bucket->bu_bhs[i]);
                        else {
                                set_buffer_uptodate(bucket->bu_bhs[i]);
                                ocfs2_set_buffer_uptodate(INODE_CACHE(bucket->bu_inode),
                                                          bucket->bu_bhs[i]);
                        }
                }
        }

        if (rc)
                ocfs2_xattr_bucket_relse(bucket);
        return rc;
}

/* Read the xattr bucket at xb_blkno */
static int ocfs2_read_xattr_bucket(struct ocfs2_xattr_bucket *bucket,
                                   u64 xb_blkno)
{
        int rc;

        rc = ocfs2_read_blocks(INODE_CACHE(bucket->bu_inode), xb_blkno,
                               bucket->bu_blocks, bucket->bu_bhs, 0,
                               NULL);
        if (!rc) {
                spin_lock(&OCFS2_SB(bucket->bu_inode->i_sb)->osb_xattr_lock);
                rc = ocfs2_validate_meta_ecc_bhs(bucket->bu_inode->i_sb,
                                                 bucket->bu_bhs,
                                                 bucket->bu_blocks,
                                                 &bucket_xh(bucket)->xh_check);
                spin_unlock(&OCFS2_SB(bucket->bu_inode->i_sb)->osb_xattr_lock);
                if (rc)
                        mlog_errno(rc);
        }

        if (rc)
                ocfs2_xattr_bucket_relse(bucket);
        return rc;
}

static int ocfs2_xattr_bucket_journal_access(handle_t *handle,
                                             struct ocfs2_xattr_bucket *bucket,
                                             int type)
{
        int i, rc = 0;

        for (i = 0; i < bucket->bu_blocks; i++) {
                rc = ocfs2_journal_access(handle,
                                          INODE_CACHE(bucket->bu_inode),
                                          bucket->bu_bhs[i], type);
                if (rc) {
                        mlog_errno(rc);
                        break;
                }
        }

        return rc;
}

static void ocfs2_xattr_bucket_journal_dirty(handle_t *handle,
                                             struct ocfs2_xattr_bucket *bucket)
{
        int i;

        spin_lock(&OCFS2_SB(bucket->bu_inode->i_sb)->osb_xattr_lock);
        ocfs2_compute_meta_ecc_bhs(bucket->bu_inode->i_sb,
                                   bucket->bu_bhs, bucket->bu_blocks,
                                   &bucket_xh(bucket)->xh_check);
        spin_unlock(&OCFS2_SB(bucket->bu_inode->i_sb)->osb_xattr_lock);

        for (i = 0; i < bucket->bu_blocks; i++)
                ocfs2_journal_dirty(handle, bucket->bu_bhs[i]);
}

static void ocfs2_xattr_bucket_copy_data(struct ocfs2_xattr_bucket *dest,
                                         struct ocfs2_xattr_bucket *src)
{
        int i;
        int blocksize = src->bu_inode->i_sb->s_blocksize;

        BUG_ON(dest->bu_blocks != src->bu_blocks);
        BUG_ON(dest->bu_inode != src->bu_inode);

        for (i = 0; i < src->bu_blocks; i++) {
                memcpy(bucket_block(dest, i), bucket_block(src, i),
                       blocksize);
        }
}

static int ocfs2_validate_xattr_block(struct super_block *sb,
                                      struct buffer_head *bh)
{
        int rc;
        struct ocfs2_xattr_block *xb =
                (struct ocfs2_xattr_block *)bh->b_data;

        trace_ocfs2_validate_xattr_block((unsigned long long)bh->b_blocknr);

        BUG_ON(!buffer_uptodate(bh));

        /*
         * If the ecc fails, we return the error but otherwise
         * leave the filesystem running.  We know any error is
         * local to this block.
         */
        rc = ocfs2_validate_meta_ecc(sb, bh->b_data, &xb->xb_check);
        if (rc)
                return rc;

        /*
         * Errors after here are fatal
         */

        if (!OCFS2_IS_VALID_XATTR_BLOCK(xb)) {
                return ocfs2_error(sb,
                                   "Extended attribute block #%llu has bad signature %.*s\n",
                                   (unsigned long long)bh->b_blocknr, 7,
                                   xb->xb_signature);
        }

        if (le64_to_cpu(xb->xb_blkno) != bh->b_blocknr) {
                return ocfs2_error(sb,
                                   "Extended attribute block #%llu has an invalid xb_blkno of %llu\n",
                                   (unsigned long long)bh->b_blocknr,
                                   (unsigned long long)le64_to_cpu(xb->xb_blkno));
        }

        if (le32_to_cpu(xb->xb_fs_generation) != OCFS2_SB(sb)->fs_generation) {
                return ocfs2_error(sb,
                                   "Extended attribute block #%llu has an invalid xb_fs_generation of #%u\n",
                                   (unsigned long long)bh->b_blocknr,
                                   le32_to_cpu(xb->xb_fs_generation));
        }

        return 0;
}

static int ocfs2_read_xattr_block(struct inode *inode, u64 xb_blkno,
                                  struct buffer_head **bh)
{
        int rc;
        struct buffer_head *tmp = *bh;

        rc = ocfs2_read_block(INODE_CACHE(inode), xb_blkno, &tmp,
                              ocfs2_validate_xattr_block);

        /* If ocfs2_read_block() got us a new bh, pass it up. */
        if (!rc && !*bh)
                *bh = tmp;

        return rc;
}

static inline const char *ocfs2_xattr_prefix(int name_index)
{
        const struct xattr_handler *handler = NULL;

        if (name_index > 0 && name_index < OCFS2_XATTR_MAX)
                handler = ocfs2_xattr_handler_map[name_index];
        return handler ? xattr_prefix(handler) : NULL;
}

static u32 ocfs2_xattr_name_hash(struct inode *inode,
                                 const char *name,
                                 int name_len)
{
        /* Get hash value of uuid from super block */
        u32 hash = OCFS2_SB(inode->i_sb)->uuid_hash;
        int i;

        /* hash extended attribute name */
        for (i = 0; i < name_len; i++) {
                hash = (hash << OCFS2_HASH_SHIFT) ^
                       (hash >> (8*sizeof(hash) - OCFS2_HASH_SHIFT)) ^
                       *name++;
        }

        return hash;
}

static int ocfs2_xattr_entry_real_size(int name_len, size_t value_len)
{
        return namevalue_size(name_len, value_len) +
                sizeof(struct ocfs2_xattr_entry);
}

static int ocfs2_xi_entry_usage(struct ocfs2_xattr_info *xi)
{
        return namevalue_size_xi(xi) +
                sizeof(struct ocfs2_xattr_entry);
}

static int ocfs2_xe_entry_usage(struct ocfs2_xattr_entry *xe)
{
        return namevalue_size_xe(xe) +
                sizeof(struct ocfs2_xattr_entry);
}

int ocfs2_calc_security_init(struct inode *dir,
                             struct ocfs2_security_xattr_info *si,
                             int *want_clusters,
                             int *xattr_credits,
                             struct ocfs2_alloc_context **xattr_ac)
{
        int ret = 0;
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
        int s_size = ocfs2_xattr_entry_real_size(strlen(si->name),
                                                 si->value_len);

        /*
         * The max space of security xattr taken inline is
         * 256(name) + 80(value) + 16(entry) = 352 bytes,
         * So reserve one metadata block for it is ok.
         */
        if (dir->i_sb->s_blocksize == OCFS2_MIN_BLOCKSIZE ||
            s_size > OCFS2_XATTR_FREE_IN_IBODY) {
                ret = ocfs2_reserve_new_metadata_blocks(osb, 1, xattr_ac);
                if (ret) {
                        mlog_errno(ret);
                        return ret;
                }
                *xattr_credits += OCFS2_XATTR_BLOCK_CREATE_CREDITS;
        }

        /* reserve clusters for xattr value which will be set in B tree*/
        if (si->value_len > OCFS2_XATTR_INLINE_SIZE) {
                int new_clusters = ocfs2_clusters_for_bytes(dir->i_sb,
                                                            si->value_len);

                *xattr_credits += ocfs2_clusters_to_blocks(dir->i_sb,
                                                           new_clusters);
                *want_clusters += new_clusters;
        }
        return ret;
}

int ocfs2_calc_xattr_init(struct inode *dir,
                          struct buffer_head *dir_bh,
                          umode_t mode,
                          struct ocfs2_security_xattr_info *si,
                          int *want_clusters,
                          int *xattr_credits,
                          int *want_meta)
{
        int ret = 0;
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
        int s_size = 0, a_size = 0, acl_len = 0, new_clusters;

        if (si->enable)
                s_size = ocfs2_xattr_entry_real_size(strlen(si->name),
                                                     si->value_len);

        if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) {
                down_read(&OCFS2_I(dir)->ip_xattr_sem);
                acl_len = ocfs2_xattr_get_nolock(dir, dir_bh,
                                        OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT,
                                        "", NULL, 0);
                up_read(&OCFS2_I(dir)->ip_xattr_sem);
                if (acl_len > 0) {
                        a_size = ocfs2_xattr_entry_real_size(0, acl_len);
                        if (S_ISDIR(mode))
                                a_size <<= 1;
                } else if (acl_len != 0 && acl_len != -ENODATA) {
                        ret = acl_len;
                        mlog_errno(ret);
                        return ret;
                }
        }

        if (!(s_size + a_size))
                return ret;

        /*
         * The max space of security xattr taken inline is
         * 256(name) + 80(value) + 16(entry) = 352 bytes,
         * The max space of acl xattr taken inline is
         * 80(value) + 16(entry) * 2(if directory) = 192 bytes,
         * when blocksize = 512, may reserve one more cluser for
         * xattr bucket, otherwise reserve one metadata block
         * for them is ok.
         * If this is a new directory with inline data,
         * we choose to reserve the entire inline area for
         * directory contents and force an external xattr block.
         */
        if (dir->i_sb->s_blocksize == OCFS2_MIN_BLOCKSIZE ||
            (S_ISDIR(mode) && ocfs2_supports_inline_data(osb)) ||
            (s_size + a_size) > OCFS2_XATTR_FREE_IN_IBODY) {
                *want_meta = *want_meta + 1;
                *xattr_credits += OCFS2_XATTR_BLOCK_CREATE_CREDITS;
        }

        if (dir->i_sb->s_blocksize == OCFS2_MIN_BLOCKSIZE &&
            (s_size + a_size) > OCFS2_XATTR_FREE_IN_BLOCK(dir)) {
                *want_clusters += 1;
                *xattr_credits += ocfs2_blocks_per_xattr_bucket(dir->i_sb);
        }

        /*
         * reserve credits and clusters for xattrs which has large value
         * and have to be set outside
         */
        if (si->enable && si->value_len > OCFS2_XATTR_INLINE_SIZE) {
                new_clusters = ocfs2_clusters_for_bytes(dir->i_sb,
                                                        si->value_len);
                *xattr_credits += ocfs2_clusters_to_blocks(dir->i_sb,
                                                           new_clusters);
                *want_clusters += new_clusters;
        }
        if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL &&
            acl_len > OCFS2_XATTR_INLINE_SIZE) {
                /* for directory, it has DEFAULT and ACCESS two types of acls */
                new_clusters = (S_ISDIR(mode) ? 2 : 1) *
                                ocfs2_clusters_for_bytes(dir->i_sb, acl_len);
                *xattr_credits += ocfs2_clusters_to_blocks(dir->i_sb,
                                                           new_clusters);
                *want_clusters += new_clusters;
        }

        return ret;
}

static int ocfs2_xattr_extend_allocation(struct inode *inode,
                                         u32 clusters_to_add,
                                         struct ocfs2_xattr_value_buf *vb,
                                         struct ocfs2_xattr_set_ctxt *ctxt)
{
        int status = 0, credits;
        handle_t *handle = ctxt->handle;
        enum ocfs2_alloc_restarted why;
        u32 prev_clusters, logical_start = le32_to_cpu(vb->vb_xv->xr_clusters);
        struct ocfs2_extent_tree et;

        ocfs2_init_xattr_value_extent_tree(&et, INODE_CACHE(inode), vb);

        while (clusters_to_add) {
                trace_ocfs2_xattr_extend_allocation(clusters_to_add);

                status = vb->vb_access(handle, INODE_CACHE(inode), vb->vb_bh,
                                       OCFS2_JOURNAL_ACCESS_WRITE);
                if (status < 0) {
                        mlog_errno(status);
                        break;
                }

                prev_clusters = le32_to_cpu(vb->vb_xv->xr_clusters);
                status = ocfs2_add_clusters_in_btree(handle,
                                                     &et,
                                                     &logical_start,
                                                     clusters_to_add,
                                                     0,
                                                     ctxt->data_ac,
                                                     ctxt->meta_ac,
                                                     &why);
                if ((status < 0) && (status != -EAGAIN)) {
                        if (status != -ENOSPC)
                                mlog_errno(status);
                        break;
                }

                ocfs2_journal_dirty(handle, vb->vb_bh);

                clusters_to_add -= le32_to_cpu(vb->vb_xv->xr_clusters) -
                                         prev_clusters;

                if (why != RESTART_NONE && clusters_to_add) {
                        /*
                         * We can only fail in case the alloc file doesn't give
                         * up enough clusters.
                         */
                        BUG_ON(why == RESTART_META);

                        credits = ocfs2_calc_extend_credits(inode->i_sb,
                                                            &vb->vb_xv->xr_list);
                        status = ocfs2_extend_trans(handle, credits);
                        if (status < 0) {
                                status = -ENOMEM;
                                mlog_errno(status);
                                break;
                        }
                }
        }

        return status;
}

static int __ocfs2_remove_xattr_range(struct inode *inode,
                                      struct ocfs2_xattr_value_buf *vb,
                                      u32 cpos, u32 phys_cpos, u32 len,
                                      unsigned int ext_flags,
                                      struct ocfs2_xattr_set_ctxt *ctxt)
{
        int ret;
        u64 phys_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys_cpos);
        handle_t *handle = ctxt->handle;
        struct ocfs2_extent_tree et;

        ocfs2_init_xattr_value_extent_tree(&et, INODE_CACHE(inode), vb);

        ret = vb->vb_access(handle, INODE_CACHE(inode), vb->vb_bh,
                            OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        ret = ocfs2_remove_extent(handle, &et, cpos, len, ctxt->meta_ac,
                                  &ctxt->dealloc);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        le32_add_cpu(&vb->vb_xv->xr_clusters, -len);
        ocfs2_journal_dirty(handle, vb->vb_bh);

        if (ext_flags & OCFS2_EXT_REFCOUNTED)
                ret = ocfs2_decrease_refcount(inode, handle,
                                        ocfs2_blocks_to_clusters(inode->i_sb,
                                                                 phys_blkno),
                                        len, ctxt->meta_ac, &ctxt->dealloc, 1);
        else
                ret = ocfs2_cache_cluster_dealloc(&ctxt->dealloc,
                                                  phys_blkno, len);
        if (ret)
                mlog_errno(ret);

out:
        return ret;
}

static int ocfs2_xattr_shrink_size(struct inode *inode,
                                   u32 old_clusters,
                                   u32 new_clusters,
                                   struct ocfs2_xattr_value_buf *vb,
                                   struct ocfs2_xattr_set_ctxt *ctxt)
{
        int ret = 0;
        unsigned int ext_flags;
        u32 trunc_len, cpos, phys_cpos, alloc_size;
        u64 block;

        if (old_clusters <= new_clusters)
                return 0;

        cpos = new_clusters;
        trunc_len = old_clusters - new_clusters;
        while (trunc_len) {
                ret = ocfs2_xattr_get_clusters(inode, cpos, &phys_cpos,
                                               &alloc_size,
                                               &vb->vb_xv->xr_list, &ext_flags);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                if (alloc_size > trunc_len)
                        alloc_size = trunc_len;

                ret = __ocfs2_remove_xattr_range(inode, vb, cpos,
                                                 phys_cpos, alloc_size,
                                                 ext_flags, ctxt);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                block = ocfs2_clusters_to_blocks(inode->i_sb, phys_cpos);
                ocfs2_remove_xattr_clusters_from_cache(INODE_CACHE(inode),
                                                       block, alloc_size);
                cpos += alloc_size;
                trunc_len -= alloc_size;
        }

out:
        return ret;
}

static int ocfs2_xattr_value_truncate(struct inode *inode,
                                      struct ocfs2_xattr_value_buf *vb,
                                      int len,
                                      struct ocfs2_xattr_set_ctxt *ctxt)
{
        int ret;
        u32 new_clusters = ocfs2_clusters_for_bytes(inode->i_sb, len);
        u32 old_clusters = le32_to_cpu(vb->vb_xv->xr_clusters);

        if (new_clusters == old_clusters)
                return 0;

        if (new_clusters > old_clusters)
                ret = ocfs2_xattr_extend_allocation(inode,
                                                    new_clusters - old_clusters,
                                                    vb, ctxt);
        else
                ret = ocfs2_xattr_shrink_size(inode,
                                              old_clusters, new_clusters,
                                              vb, ctxt);

        return ret;
}

static int ocfs2_xattr_list_entry(struct super_block *sb,
                                  char *buffer, size_t size,
                                  size_t *result, int type,
                                  const char *name, int name_len)
{
        char *p = buffer + *result;
        const char *prefix;
        int prefix_len;
        int total_len;

        switch(type) {
        case OCFS2_XATTR_INDEX_USER:
                if (OCFS2_SB(sb)->s_mount_opt & OCFS2_MOUNT_NOUSERXATTR)
                        return 0;
                break;

        case OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS:
        case OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT:
                if (!(sb->s_flags & SB_POSIXACL))
                        return 0;
                break;

        case OCFS2_XATTR_INDEX_TRUSTED:
                if (!capable(CAP_SYS_ADMIN))
                        return 0;
                break;
        }

        prefix = ocfs2_xattr_prefix(type);
        if (!prefix)
                return 0;
        prefix_len = strlen(prefix);
        total_len = prefix_len + name_len + 1;
        *result += total_len;

        /* we are just looking for how big our buffer needs to be */
        if (!size)
                return 0;

        if (*result > size)
                return -ERANGE;

        memcpy(p, prefix, prefix_len);
        memcpy(p + prefix_len, name, name_len);
        p[prefix_len + name_len] = '\0';

        return 0;
}

static int ocfs2_xattr_list_entries(struct inode *inode,
                                    struct ocfs2_xattr_header *header,
                                    char *buffer, size_t buffer_size)
{
        size_t result = 0;
        int i, type, ret;
        const char *name;

        for (i = 0 ; i < le16_to_cpu(header->xh_count); i++) {
                struct ocfs2_xattr_entry *entry = &header->xh_entries[i];
                type = ocfs2_xattr_get_type(entry);
                name = (const char *)header +
                        le16_to_cpu(entry->xe_name_offset);

                ret = ocfs2_xattr_list_entry(inode->i_sb,
                                             buffer, buffer_size,
                                             &result, type, name,
                                             entry->xe_name_len);
                if (ret)
                        return ret;
        }

        return result;
}

int ocfs2_has_inline_xattr_value_outside(struct inode *inode,
                                         struct ocfs2_dinode *di)
{
        struct ocfs2_xattr_header *xh;
        int i;

        xh = (struct ocfs2_xattr_header *)
                 ((void *)di + inode->i_sb->s_blocksize -
                 le16_to_cpu(di->i_xattr_inline_size));

        for (i = 0; i < le16_to_cpu(xh->xh_count); i++)
                if (!ocfs2_xattr_is_local(&xh->xh_entries[i]))
                        return 1;

        return 0;
}

static int ocfs2_xattr_ibody_list(struct inode *inode,
                                  struct ocfs2_dinode *di,
                                  char *buffer,
                                  size_t buffer_size)
{
        struct ocfs2_xattr_header *header = NULL;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        int ret = 0;

        if (!(oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL))
                return ret;

        header = (struct ocfs2_xattr_header *)
                 ((void *)di + inode->i_sb->s_blocksize -
                 le16_to_cpu(di->i_xattr_inline_size));

        ret = ocfs2_xattr_list_entries(inode, header, buffer, buffer_size);

        return ret;
}

static int ocfs2_xattr_block_list(struct inode *inode,
                                  struct ocfs2_dinode *di,
                                  char *buffer,
                                  size_t buffer_size)
{
        struct buffer_head *blk_bh = NULL;
        struct ocfs2_xattr_block *xb;
        int ret = 0;

        if (!di->i_xattr_loc)

                return ret;

        ret = ocfs2_read_xattr_block(inode, le64_to_cpu(di->i_xattr_loc),
                                     &blk_bh);
        if (ret < 0) {
                mlog_errno(ret);
                return ret;
        }

        xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
        if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) {
                struct ocfs2_xattr_header *header = &xb->xb_attrs.xb_header;
                ret = ocfs2_xattr_list_entries(inode, header,
                                               buffer, buffer_size);
        } else
                ret = ocfs2_xattr_tree_list_index_block(inode, blk_bh,
                                                   buffer, buffer_size);

        brelse(blk_bh);

        return ret;
}

ssize_t ocfs2_listxattr(struct dentry *dentry,
                        char *buffer,
                        size_t size)
{
        int ret = 0, i_ret = 0, b_ret = 0;
        struct buffer_head *di_bh = NULL;
        struct ocfs2_dinode *di = NULL;
        struct ocfs2_inode_info *oi = OCFS2_I(d_inode(dentry));

        if (!ocfs2_supports_xattr(OCFS2_SB(dentry->d_sb)))
                return -EOPNOTSUPP;

        if (!(oi->ip_dyn_features & OCFS2_HAS_XATTR_FL))
                return ret;

        ret = ocfs2_inode_lock(d_inode(dentry), &di_bh, 0);
        if (ret < 0) {
                mlog_errno(ret);
                return ret;
        }

        di = (struct ocfs2_dinode *)di_bh->b_data;

        down_read(&oi->ip_xattr_sem);
        i_ret = ocfs2_xattr_ibody_list(d_inode(dentry), di, buffer, size);
        if (i_ret < 0)
                b_ret = 0;
        else {
                if (buffer) {
                        buffer += i_ret;
                        size -= i_ret;
                }
                b_ret = ocfs2_xattr_block_list(d_inode(dentry), di,
                                               buffer, size);
                if (b_ret < 0)
                        i_ret = 0;
        }
        up_read(&oi->ip_xattr_sem);
        ocfs2_inode_unlock(d_inode(dentry), 0);

        brelse(di_bh);

        return i_ret + b_ret;
}

static int ocfs2_xattr_find_entry(int name_index,
                                  const char *name,
                                  struct ocfs2_xattr_search *xs)
{
        struct ocfs2_xattr_entry *entry;
        size_t name_len;
        int i, cmp = 1;

        if (name == NULL)
                return -EINVAL;

        name_len = strlen(name);
        entry = xs->here;
        for (i = 0; i < le16_to_cpu(xs->header->xh_count); i++) {
                cmp = name_index - ocfs2_xattr_get_type(entry);
                if (!cmp)
                        cmp = name_len - entry->xe_name_len;
                if (!cmp)
                        cmp = memcmp(name, (xs->base +
                                     le16_to_cpu(entry->xe_name_offset)),
                                     name_len);
                if (cmp == 0)
                        break;
                entry += 1;
        }
        xs->here = entry;

        return cmp ? -ENODATA : 0;
}

static int ocfs2_xattr_get_value_outside(struct inode *inode,
                                         struct ocfs2_xattr_value_root *xv,
                                         void *buffer,
                                         size_t len)
{
        u32 cpos, p_cluster, num_clusters, bpc, clusters;
        u64 blkno;
        int i, ret = 0;
        size_t cplen, blocksize;
        struct buffer_head *bh = NULL;
        struct ocfs2_extent_list *el;

        el = &xv->xr_list;
        clusters = le32_to_cpu(xv->xr_clusters);
        bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
        blocksize = inode->i_sb->s_blocksize;

        cpos = 0;
        while (cpos < clusters) {
                ret = ocfs2_xattr_get_clusters(inode, cpos, &p_cluster,
                                               &num_clusters, el, NULL);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                blkno = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
                /* Copy ocfs2_xattr_value */
                for (i = 0; i < num_clusters * bpc; i++, blkno++) {
                        ret = ocfs2_read_block(INODE_CACHE(inode), blkno,
                                               &bh, NULL);
                        if (ret) {
                                mlog_errno(ret);
                                goto out;
                        }

                        cplen = len >= blocksize ? blocksize : len;
                        memcpy(buffer, bh->b_data, cplen);
                        len -= cplen;
                        buffer += cplen;

                        brelse(bh);
                        bh = NULL;
                        if (len == 0)
                                break;
                }
                cpos += num_clusters;
        }
out:
        return ret;
}

static int ocfs2_xattr_ibody_get(struct inode *inode,
                                 int name_index,
                                 const char *name,
                                 void *buffer,
                                 size_t buffer_size,
                                 struct ocfs2_xattr_search *xs)
{
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)xs->inode_bh->b_data;
        struct ocfs2_xattr_value_root *xv;
        size_t size;
        int ret = 0;

        if (!(oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL))
                return -ENODATA;

        xs->end = (void *)di + inode->i_sb->s_blocksize;
        xs->header = (struct ocfs2_xattr_header *)
                        (xs->end - le16_to_cpu(di->i_xattr_inline_size));
        xs->base = (void *)xs->header;
        xs->here = xs->header->xh_entries;

        ret = ocfs2_xattr_find_entry(name_index, name, xs);
        if (ret)
                return ret;
        size = le64_to_cpu(xs->here->xe_value_size);
        if (buffer) {
                if (size > buffer_size)
                        return -ERANGE;
                if (ocfs2_xattr_is_local(xs->here)) {
                        memcpy(buffer, (void *)xs->base +
                               le16_to_cpu(xs->here->xe_name_offset) +
                               OCFS2_XATTR_SIZE(xs->here->xe_name_len), size);
                } else {
                        xv = (struct ocfs2_xattr_value_root *)
                                (xs->base + le16_to_cpu(
                                 xs->here->xe_name_offset) +
                                OCFS2_XATTR_SIZE(xs->here->xe_name_len));
                        ret = ocfs2_xattr_get_value_outside(inode, xv,
                                                            buffer, size);
                        if (ret < 0) {
                                mlog_errno(ret);
                                return ret;
                        }
                }
        }

        return size;
}

static int ocfs2_xattr_block_get(struct inode *inode,
                                 int name_index,
                                 const char *name,
                                 void *buffer,
                                 size_t buffer_size,
                                 struct ocfs2_xattr_search *xs)
{
        struct ocfs2_xattr_block *xb;
        struct ocfs2_xattr_value_root *xv;
        size_t size;
        int ret = -ENODATA, name_offset, name_len, i;
        int block_off;

        xs->bucket = ocfs2_xattr_bucket_new(inode);
        if (!xs->bucket) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto cleanup;
        }

        ret = ocfs2_xattr_block_find(inode, name_index, name, xs);
        if (ret) {
                mlog_errno(ret);
                goto cleanup;
        }

        if (xs->not_found) {
                ret = -ENODATA;
                goto cleanup;
        }

        xb = (struct ocfs2_xattr_block *)xs->xattr_bh->b_data;
        size = le64_to_cpu(xs->here->xe_value_size);
        if (buffer) {
                ret = -ERANGE;
                if (size > buffer_size)
                        goto cleanup;

                name_offset = le16_to_cpu(xs->here->xe_name_offset);
                name_len = OCFS2_XATTR_SIZE(xs->here->xe_name_len);
                i = xs->here - xs->header->xh_entries;

                if (le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED) {
                        ret = ocfs2_xattr_bucket_get_name_value(inode->i_sb,
                                                                bucket_xh(xs->bucket),
                                                                i,
                                                                &block_off,
                                                                &name_offset);
                        if (ret) {
                                mlog_errno(ret);
                                goto cleanup;
                        }
                        xs->base = bucket_block(xs->bucket, block_off);
                }
                if (ocfs2_xattr_is_local(xs->here)) {
                        memcpy(buffer, (void *)xs->base +
                               name_offset + name_len, size);
                } else {
                        xv = (struct ocfs2_xattr_value_root *)
                                (xs->base + name_offset + name_len);
                        ret = ocfs2_xattr_get_value_outside(inode, xv,
                                                            buffer, size);
                        if (ret < 0) {
                                mlog_errno(ret);
                                goto cleanup;
                        }
                }
        }
        ret = size;
cleanup:
        ocfs2_xattr_bucket_free(xs->bucket);

        brelse(xs->xattr_bh);
        xs->xattr_bh = NULL;
        return ret;
}

int ocfs2_xattr_get_nolock(struct inode *inode,
                           struct buffer_head *di_bh,
                           int name_index,
                           const char *name,
                           void *buffer,
                           size_t buffer_size)
{
        int ret;
        struct ocfs2_dinode *di = NULL;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_xattr_search xis = {
                .not_found = -ENODATA,
        };
        struct ocfs2_xattr_search xbs = {
                .not_found = -ENODATA,
        };

        if (!ocfs2_supports_xattr(OCFS2_SB(inode->i_sb)))
                return -EOPNOTSUPP;

        if (!(oi->ip_dyn_features & OCFS2_HAS_XATTR_FL))
                return -ENODATA;

        xis.inode_bh = xbs.inode_bh = di_bh;
        di = (struct ocfs2_dinode *)di_bh->b_data;

        ret = ocfs2_xattr_ibody_get(inode, name_index, name, buffer,
                                    buffer_size, &xis);
        if (ret == -ENODATA && di->i_xattr_loc)
                ret = ocfs2_xattr_block_get(inode, name_index, name, buffer,
                                            buffer_size, &xbs);

        return ret;
}

/* ocfs2_xattr_get()
 *
 * Copy an extended attribute into the buffer provided.
 * Buffer is NULL to compute the size of buffer required.
 */
static int ocfs2_xattr_get(struct inode *inode,
                           int name_index,
                           const char *name,
                           void *buffer,
                           size_t buffer_size)
{
        int ret, had_lock;
        struct buffer_head *di_bh = NULL;
        struct ocfs2_lock_holder oh;

        had_lock = ocfs2_inode_lock_tracker(inode, &di_bh, 0, &oh);
        if (had_lock < 0) {
                mlog_errno(had_lock);
                return had_lock;
        }
        down_read(&OCFS2_I(inode)->ip_xattr_sem);
        ret = ocfs2_xattr_get_nolock(inode, di_bh, name_index,
                                     name, buffer, buffer_size);
        up_read(&OCFS2_I(inode)->ip_xattr_sem);

        ocfs2_inode_unlock_tracker(inode, 0, &oh, had_lock);

        brelse(di_bh);

        return ret;
}

static int __ocfs2_xattr_set_value_outside(struct inode *inode,
                                           handle_t *handle,
                                           struct ocfs2_xattr_value_buf *vb,
                                           const void *value,
                                           int value_len)
{
        int ret = 0, i, cp_len;
        u16 blocksize = inode->i_sb->s_blocksize;
        u32 p_cluster, num_clusters;
        u32 cpos = 0, bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
        u32 clusters = ocfs2_clusters_for_bytes(inode->i_sb, value_len);
        u64 blkno;
        struct buffer_head *bh = NULL;
        unsigned int ext_flags;
        struct ocfs2_xattr_value_root *xv = vb->vb_xv;

        BUG_ON(clusters > le32_to_cpu(xv->xr_clusters));

        while (cpos < clusters) {
                ret = ocfs2_xattr_get_clusters(inode, cpos, &p_cluster,
                                               &num_clusters, &xv->xr_list,
                                               &ext_flags);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);

                blkno = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);

                for (i = 0; i < num_clusters * bpc; i++, blkno++) {
                        ret = ocfs2_read_block(INODE_CACHE(inode), blkno,
                                               &bh, NULL);
                        if (ret) {
                                mlog_errno(ret);
                                goto out;
                        }

                        ret = ocfs2_journal_access(handle,
                                                   INODE_CACHE(inode),
                                                   bh,
                                                   OCFS2_JOURNAL_ACCESS_WRITE);
                        if (ret < 0) {
                                mlog_errno(ret);
                                goto out;
                        }

                        cp_len = value_len > blocksize ? blocksize : value_len;
                        memcpy(bh->b_data, value, cp_len);
                        value_len -= cp_len;
                        value += cp_len;
                        if (cp_len < blocksize)
                                memset(bh->b_data + cp_len, 0,
                                       blocksize - cp_len);

                        ocfs2_journal_dirty(handle, bh);
                        brelse(bh);
                        bh = NULL;

                        /*
                         * XXX: do we need to empty all the following
                         * blocks in this cluster?
                         */
                        if (!value_len)
                                break;
                }
                cpos += num_clusters;
        }
out:
        brelse(bh);

        return ret;
}

static int ocfs2_xa_check_space_helper(int needed_space, int free_start,
                                       int num_entries)
{
        int free_space;

        if (!needed_space)
                return 0;

        free_space = free_start -
                sizeof(struct ocfs2_xattr_header) -
                (num_entries * sizeof(struct ocfs2_xattr_entry)) -
                OCFS2_XATTR_HEADER_GAP;
        if (free_space < 0)
                return -EIO;
        if (free_space < needed_space)
                return -ENOSPC;

        return 0;
}

static int ocfs2_xa_journal_access(handle_t *handle, struct ocfs2_xa_loc *loc,
                                   int type)
{
        return loc->xl_ops->xlo_journal_access(handle, loc, type);
}

static void ocfs2_xa_journal_dirty(handle_t *handle, struct ocfs2_xa_loc *loc)
{
        loc->xl_ops->xlo_journal_dirty(handle, loc);
}

/* Give a pointer into the storage for the given offset */
static void *ocfs2_xa_offset_pointer(struct ocfs2_xa_loc *loc, int offset)
{
        BUG_ON(offset >= loc->xl_size);
        return loc->xl_ops->xlo_offset_pointer(loc, offset);
}

/*
 * Wipe the name+value pair and allow the storage to reclaim it.  This
 * must be followed by either removal of the entry or a call to
 * ocfs2_xa_add_namevalue().
 */
static void ocfs2_xa_wipe_namevalue(struct ocfs2_xa_loc *loc)
{
        loc->xl_ops->xlo_wipe_namevalue(loc);
}

/*
 * Find lowest offset to a name+value pair.  This is the start of our
 * downward-growing free space.
 */
static int ocfs2_xa_get_free_start(struct ocfs2_xa_loc *loc)
{
        return loc->xl_ops->xlo_get_free_start(loc);
}

/* Can we reuse loc->xl_entry for xi? */
static int ocfs2_xa_can_reuse_entry(struct ocfs2_xa_loc *loc,
                                    struct ocfs2_xattr_info *xi)
{
        return loc->xl_ops->xlo_can_reuse(loc, xi);
}

/* How much free space is needed to set the new value */
static int ocfs2_xa_check_space(struct ocfs2_xa_loc *loc,
                                struct ocfs2_xattr_info *xi)
{
        return loc->xl_ops->xlo_check_space(loc, xi);
}

static void ocfs2_xa_add_entry(struct ocfs2_xa_loc *loc, u32 name_hash)
{
        loc->xl_ops->xlo_add_entry(loc, name_hash);
        loc->xl_entry->xe_name_hash = cpu_to_le32(name_hash);
        /*
         * We can't leave the new entry's xe_name_offset at zero or
         * add_namevalue() will go nuts.  We set it to the size of our
         * storage so that it can never be less than any other entry.
         */
        loc->xl_entry->xe_name_offset = cpu_to_le16(loc->xl_size);
}

static void ocfs2_xa_add_namevalue(struct ocfs2_xa_loc *loc,
                                   struct ocfs2_xattr_info *xi)
{
        int size = namevalue_size_xi(xi);
        int nameval_offset;
        char *nameval_buf;

        loc->xl_ops->xlo_add_namevalue(loc, size);
        loc->xl_entry->xe_value_size = cpu_to_le64(xi->xi_value_len);
        loc->xl_entry->xe_name_len = xi->xi_name_len;
        ocfs2_xattr_set_type(loc->xl_entry, xi->xi_name_index);
        ocfs2_xattr_set_local(loc->xl_entry,
                              xi->xi_value_len <= OCFS2_XATTR_INLINE_SIZE);

        nameval_offset = le16_to_cpu(loc->xl_entry->xe_name_offset);
        nameval_buf = ocfs2_xa_offset_pointer(loc, nameval_offset);
        memset(nameval_buf, 0, size);
        memcpy(nameval_buf, xi->xi_name, xi->xi_name_len);
}

static void ocfs2_xa_fill_value_buf(struct ocfs2_xa_loc *loc,
                                    struct ocfs2_xattr_value_buf *vb)
{
        int nameval_offset = le16_to_cpu(loc->xl_entry->xe_name_offset);
        int name_size = OCFS2_XATTR_SIZE(loc->xl_entry->xe_name_len);

        /* Value bufs are for value trees */
        BUG_ON(ocfs2_xattr_is_local(loc->xl_entry));
        BUG_ON(namevalue_size_xe(loc->xl_entry) !=
               (name_size + OCFS2_XATTR_ROOT_SIZE));

        loc->xl_ops->xlo_fill_value_buf(loc, vb);
        vb->vb_xv =
                (struct ocfs2_xattr_value_root *)ocfs2_xa_offset_pointer(loc,
                                                        nameval_offset +
                                                        name_size);
}

static int ocfs2_xa_block_journal_access(handle_t *handle,
                                         struct ocfs2_xa_loc *loc, int type)
{
        struct buffer_head *bh = loc->xl_storage;
        ocfs2_journal_access_func access;

        if (loc->xl_size == (bh->b_size -
                             offsetof(struct ocfs2_xattr_block,
                                      xb_attrs.xb_header)))
                access = ocfs2_journal_access_xb;
        else
                access = ocfs2_journal_access_di;
        return access(handle, INODE_CACHE(loc->xl_inode), bh, type);
}

static void ocfs2_xa_block_journal_dirty(handle_t *handle,
                                         struct ocfs2_xa_loc *loc)
{
        struct buffer_head *bh = loc->xl_storage;

        ocfs2_journal_dirty(handle, bh);
}

static void *ocfs2_xa_block_offset_pointer(struct ocfs2_xa_loc *loc,
                                           int offset)
{
        return (char *)loc->xl_header + offset;
}

static int ocfs2_xa_block_can_reuse(struct ocfs2_xa_loc *loc,
                                    struct ocfs2_xattr_info *xi)
{
        /*
         * Block storage is strict.  If the sizes aren't exact, we will
         * remove the old one and reinsert the new.
         */
        return namevalue_size_xe(loc->xl_entry) ==
                namevalue_size_xi(xi);
}

static int ocfs2_xa_block_get_free_start(struct ocfs2_xa_loc *loc)
{
        struct ocfs2_xattr_header *xh = loc->xl_header;
        int i, count = le16_to_cpu(xh->xh_count);
        int offset, free_start = loc->xl_size;

        for (i = 0; i < count; i++) {
                offset = le16_to_cpu(xh->xh_entries[i].xe_name_offset);
                if (offset < free_start)
                        free_start = offset;
        }

        return free_start;
}

static int ocfs2_xa_block_check_space(struct ocfs2_xa_loc *loc,
                                      struct ocfs2_xattr_info *xi)
{
        int count = le16_to_cpu(loc->xl_header->xh_count);
        int free_start = ocfs2_xa_get_free_start(loc);
        int needed_space = ocfs2_xi_entry_usage(xi);

        /*
         * Block storage will reclaim the original entry before inserting
         * the new value, so we only need the difference.  If the new
         * entry is smaller than the old one, we don't need anything.
         */
        if (loc->xl_entry) {
                /* Don't need space if we're reusing! */
                if (ocfs2_xa_can_reuse_entry(loc, xi))
                        needed_space = 0;
                else
                        needed_space -= ocfs2_xe_entry_usage(loc->xl_entry);
        }
        if (needed_space < 0)
                needed_space = 0;
        return ocfs2_xa_check_space_helper(needed_space, free_start, count);
}

/*
 * Block storage for xattrs keeps the name+value pairs compacted.  When
 * we remove one, we have to shift any that preceded it towards the end.
 */
static void ocfs2_xa_block_wipe_namevalue(struct ocfs2_xa_loc *loc)
{
        int i, offset;
        int namevalue_offset, first_namevalue_offset, namevalue_size;
        struct ocfs2_xattr_entry *entry = loc->xl_entry;
        struct ocfs2_xattr_header *xh = loc->xl_header;
        int count = le16_to_cpu(xh->xh_count);

        namevalue_offset = le16_to_cpu(entry->xe_name_offset);
        namevalue_size = namevalue_size_xe(entry);
        first_namevalue_offset = ocfs2_xa_get_free_start(loc);

        /* Shift the name+value pairs */
        memmove((char *)xh + first_namevalue_offset + namevalue_size,
                (char *)xh + first_namevalue_offset,
                namevalue_offset - first_namevalue_offset);
        memset((char *)xh + first_namevalue_offset, 0, namevalue_size);

        /* Now tell xh->xh_entries about it */
        for (i = 0; i < count; i++) {
                offset = le16_to_cpu(xh->xh_entries[i].xe_name_offset);
                if (offset <= namevalue_offset)
                        le16_add_cpu(&xh->xh_entries[i].xe_name_offset,
                                     namevalue_size);
        }

        /*
         * Note that we don't update xh_free_start or xh_name_value_len
         * because they're not used in block-stored xattrs.
         */
}

static void ocfs2_xa_block_add_entry(struct ocfs2_xa_loc *loc, u32 name_hash)
{
        int count = le16_to_cpu(loc->xl_header->xh_count);
        loc->xl_entry = &(loc->xl_header->xh_entries[count]);
        le16_add_cpu(&loc->xl_header->xh_count, 1);
        memset(loc->xl_entry, 0, sizeof(struct ocfs2_xattr_entry));
}

static void ocfs2_xa_block_add_namevalue(struct ocfs2_xa_loc *loc, int size)
{
        int free_start = ocfs2_xa_get_free_start(loc);

        loc->xl_entry->xe_name_offset = cpu_to_le16(free_start - size);
}

static void ocfs2_xa_block_fill_value_buf(struct ocfs2_xa_loc *loc,
                                          struct ocfs2_xattr_value_buf *vb)
{
        struct buffer_head *bh = loc->xl_storage;

        if (loc->xl_size == (bh->b_size -
                             offsetof(struct ocfs2_xattr_block,
                                      xb_attrs.xb_header)))
                vb->vb_access = ocfs2_journal_access_xb;
        else
                vb->vb_access = ocfs2_journal_access_di;
        vb->vb_bh = bh;
}

/*
 * Operations for xattrs stored in blocks.  This includes inline inode
 * storage and unindexed ocfs2_xattr_blocks.
 */
static const struct ocfs2_xa_loc_operations ocfs2_xa_block_loc_ops = {
        .xlo_journal_access     = ocfs2_xa_block_journal_access,
        .xlo_journal_dirty      = ocfs2_xa_block_journal_dirty,
        .xlo_offset_pointer     = ocfs2_xa_block_offset_pointer,
        .xlo_check_space        = ocfs2_xa_block_check_space,
        .xlo_can_reuse          = ocfs2_xa_block_can_reuse,
        .xlo_get_free_start     = ocfs2_xa_block_get_free_start,
        .xlo_wipe_namevalue     = ocfs2_xa_block_wipe_namevalue,
        .xlo_add_entry          = ocfs2_xa_block_add_entry,
        .xlo_add_namevalue      = ocfs2_xa_block_add_namevalue,
        .xlo_fill_value_buf     = ocfs2_xa_block_fill_value_buf,
};

static int ocfs2_xa_bucket_journal_access(handle_t *handle,
                                          struct ocfs2_xa_loc *loc, int type)
{
        struct ocfs2_xattr_bucket *bucket = loc->xl_storage;

        return ocfs2_xattr_bucket_journal_access(handle, bucket, type);
}

static void ocfs2_xa_bucket_journal_dirty(handle_t *handle,
                                          struct ocfs2_xa_loc *loc)
{
        struct ocfs2_xattr_bucket *bucket = loc->xl_storage;

        ocfs2_xattr_bucket_journal_dirty(handle, bucket);
}

static void *ocfs2_xa_bucket_offset_pointer(struct ocfs2_xa_loc *loc,
                                            int offset)
{
        struct ocfs2_xattr_bucket *bucket = loc->xl_storage;
        int block, block_offset;

        /* The header is at the front of the bucket */
        block = offset >> loc->xl_inode->i_sb->s_blocksize_bits;
        block_offset = offset % loc->xl_inode->i_sb->s_blocksize;

        return bucket_block(bucket, block) + block_offset;
}

static int ocfs2_xa_bucket_can_reuse(struct ocfs2_xa_loc *loc,
                                     struct ocfs2_xattr_info *xi)
{
        return namevalue_size_xe(loc->xl_entry) >=
                namevalue_size_xi(xi);
}

static int ocfs2_xa_bucket_get_free_start(struct ocfs2_xa_loc *loc)
{
        struct ocfs2_xattr_bucket *bucket = loc->xl_storage;
        return le16_to_cpu(bucket_xh(bucket)->xh_free_start);
}

static int ocfs2_bucket_align_free_start(struct super_block *sb,
                                         int free_start, int size)
{
        /*
         * We need to make sure that the name+value pair fits within
         * one block.
         */
        if (((free_start - size) >> sb->s_blocksize_bits) !=
            ((free_start - 1) >> sb->s_blocksize_bits))
                free_start -= free_start % sb->s_blocksize;

        return free_start;
}

static int ocfs2_xa_bucket_check_space(struct ocfs2_xa_loc *loc,
                                       struct ocfs2_xattr_info *xi)
{
        int rc;
        int count = le16_to_cpu(loc->xl_header->xh_count);
        int free_start = ocfs2_xa_get_free_start(loc);
        int needed_space = ocfs2_xi_entry_usage(xi);
        int size = namevalue_size_xi(xi);
        struct super_block *sb = loc->xl_inode->i_sb;

        /*
         * Bucket storage does not reclaim name+value pairs it cannot
         * reuse.  They live as holes until the bucket fills, and then
         * the bucket is defragmented.  However, the bucket can reclaim
         * the ocfs2_xattr_entry.
         */
        if (loc->xl_entry) {
                /* Don't need space if we're reusing! */
                if (ocfs2_xa_can_reuse_entry(loc, xi))
                        needed_space = 0;
                else
                        needed_space -= sizeof(struct ocfs2_xattr_entry);
        }
        BUG_ON(needed_space < 0);

        if (free_start < size) {
                if (needed_space)
                        return -ENOSPC;
        } else {
                /*
                 * First we check if it would fit in the first place.
                 * Below, we align the free start to a block.  This may
                 * slide us below the minimum gap.  By checking unaligned
                 * first, we avoid that error.
                 */
                rc = ocfs2_xa_check_space_helper(needed_space, free_start,
                                                 count);
                if (rc)
                        return rc;
                free_start = ocfs2_bucket_align_free_start(sb, free_start,
                                                           size);
        }
        return ocfs2_xa_check_space_helper(needed_space, free_start, count);
}

static void ocfs2_xa_bucket_wipe_namevalue(struct ocfs2_xa_loc *loc)
{
        le16_add_cpu(&loc->xl_header->xh_name_value_len,
                     -namevalue_size_xe(loc->xl_entry));
}

static void ocfs2_xa_bucket_add_entry(struct ocfs2_xa_loc *loc, u32 name_hash)
{
        struct ocfs2_xattr_header *xh = loc->xl_header;
        int count = le16_to_cpu(xh->xh_count);
        int low = 0, high = count - 1, tmp;
        struct ocfs2_xattr_entry *tmp_xe;

        /*
         * We keep buckets sorted by name_hash, so we need to find
         * our insert place.
         */
        while (low <= high && count) {
                tmp = (low + high) / 2;
                tmp_xe = &xh->xh_entries[tmp];

                if (name_hash > le32_to_cpu(tmp_xe->xe_name_hash))
                        low = tmp + 1;
                else if (name_hash < le32_to_cpu(tmp_xe->xe_name_hash))
                        high = tmp - 1;
                else {
                        low = tmp;
                        break;
                }
        }

        if (low != count)
                memmove(&xh->xh_entries[low + 1],
                        &xh->xh_entries[low],
                        ((count - low) * sizeof(struct ocfs2_xattr_entry)));

        le16_add_cpu(&xh->xh_count, 1);
        loc->xl_entry = &xh->xh_entries[low];
        memset(loc->xl_entry, 0, sizeof(struct ocfs2_xattr_entry));
}

static void ocfs2_xa_bucket_add_namevalue(struct ocfs2_xa_loc *loc, int size)
{
        int free_start = ocfs2_xa_get_free_start(loc);
        struct ocfs2_xattr_header *xh = loc->xl_header;
        struct super_block *sb = loc->xl_inode->i_sb;
        int nameval_offset;

        free_start = ocfs2_bucket_align_free_start(sb, free_start, size);
        nameval_offset = free_start - size;
        loc->xl_entry->xe_name_offset = cpu_to_le16(nameval_offset);
        xh->xh_free_start = cpu_to_le16(nameval_offset);
        le16_add_cpu(&xh->xh_name_value_len, size);

}

static void ocfs2_xa_bucket_fill_value_buf(struct ocfs2_xa_loc *loc,
                                           struct ocfs2_xattr_value_buf *vb)
{
        struct ocfs2_xattr_bucket *bucket = loc->xl_storage;
        struct super_block *sb = loc->xl_inode->i_sb;
        int nameval_offset = le16_to_cpu(loc->xl_entry->xe_name_offset);
        int size = namevalue_size_xe(loc->xl_entry);
        int block_offset = nameval_offset >> sb->s_blocksize_bits;

        /* Values are not allowed to straddle block boundaries */
        BUG_ON(block_offset !=
               ((nameval_offset + size - 1) >> sb->s_blocksize_bits));
        /* We expect the bucket to be filled in */
        BUG_ON(!bucket->bu_bhs[block_offset]);

        vb->vb_access = ocfs2_journal_access;
        vb->vb_bh = bucket->bu_bhs[block_offset];
}

/* Operations for xattrs stored in buckets. */
static const struct ocfs2_xa_loc_operations ocfs2_xa_bucket_loc_ops = {
        .xlo_journal_access     = ocfs2_xa_bucket_journal_access,
        .xlo_journal_dirty      = ocfs2_xa_bucket_journal_dirty,
        .xlo_offset_pointer     = ocfs2_xa_bucket_offset_pointer,
        .xlo_check_space        = ocfs2_xa_bucket_check_space,
        .xlo_can_reuse          = ocfs2_xa_bucket_can_reuse,
        .xlo_get_free_start     = ocfs2_xa_bucket_get_free_start,
        .xlo_wipe_namevalue     = ocfs2_xa_bucket_wipe_namevalue,
        .xlo_add_entry          = ocfs2_xa_bucket_add_entry,
        .xlo_add_namevalue      = ocfs2_xa_bucket_add_namevalue,
        .xlo_fill_value_buf     = ocfs2_xa_bucket_fill_value_buf,
};

static unsigned int ocfs2_xa_value_clusters(struct ocfs2_xa_loc *loc)
{
        struct ocfs2_xattr_value_buf vb;

        if (ocfs2_xattr_is_local(loc->xl_entry))
                return 0;

        ocfs2_xa_fill_value_buf(loc, &vb);
        return le32_to_cpu(vb.vb_xv->xr_clusters);
}

static int ocfs2_xa_value_truncate(struct ocfs2_xa_loc *loc, u64 bytes,
                                   struct ocfs2_xattr_set_ctxt *ctxt)
{
        int trunc_rc, access_rc;
        struct ocfs2_xattr_value_buf vb;

        ocfs2_xa_fill_value_buf(loc, &vb);
        trunc_rc = ocfs2_xattr_value_truncate(loc->xl_inode, &vb, bytes,
                                              ctxt);

        /*
         * The caller of ocfs2_xa_value_truncate() has already called
         * ocfs2_xa_journal_access on the loc.  However, The truncate code
         * calls ocfs2_extend_trans().  This may commit the previous
         * transaction and open a new one.  If this is a bucket, truncate
         * could leave only vb->vb_bh set up for journaling.  Meanwhile,
         * the caller is expecting to dirty the entire bucket.  So we must
         * reset the journal work.  We do this even if truncate has failed,
         * as it could have failed after committing the extend.
         */
        access_rc = ocfs2_xa_journal_access(ctxt->handle, loc,
                                            OCFS2_JOURNAL_ACCESS_WRITE);

        /* Errors in truncate take precedence */
        return trunc_rc ? trunc_rc : access_rc;
}

static void ocfs2_xa_remove_entry(struct ocfs2_xa_loc *loc)
{
        int index, count;
        struct ocfs2_xattr_header *xh = loc->xl_header;
        struct ocfs2_xattr_entry *entry = loc->xl_entry;

        ocfs2_xa_wipe_namevalue(loc);
        loc->xl_entry = NULL;

        le16_add_cpu(&xh->xh_count, -1);
        count = le16_to_cpu(xh->xh_count);

        /*
         * Only zero out the entry if there are more remaining.  This is
         * important for an empty bucket, as it keeps track of the
         * bucket's hash value.  It doesn't hurt empty block storage.
         */
        if (count) {
                index = ((char *)entry - (char *)&xh->xh_entries) /
                        sizeof(struct ocfs2_xattr_entry);
                memmove(&xh->xh_entries[index], &xh->xh_entries[index + 1],
                        (count - index) * sizeof(struct ocfs2_xattr_entry));
                memset(&xh->xh_entries[count], 0,
                       sizeof(struct ocfs2_xattr_entry));
        }
}

/*
 * If we have a problem adjusting the size of an external value during
 * ocfs2_xa_prepare_entry() or ocfs2_xa_remove(), we may have an xattr
 * in an intermediate state.  For example, the value may be partially
 * truncated.
 *
 * If the value tree hasn't changed, the extend/truncate went nowhere.
 * We have nothing to do.  The caller can treat it as a straight error.
 *
 * If the value tree got partially truncated, we now have a corrupted
 * extended attribute.  We're going to wipe its entry and leak the
 * clusters.  Better to leak some storage than leave a corrupt entry.
 *
 * If the value tree grew, it obviously didn't grow enough for the
 * new entry.  We're not going to try and reclaim those clusters either.
 * If there was already an external value there (orig_clusters != 0),
 * the new clusters are attached safely and we can just leave the old
 * value in place.  If there was no external value there, we remove
 * the entry.
 *
 * This way, the xattr block we store in the journal will be consistent.
 * If the size change broke because of the journal, no changes will hit
 * disk anyway.
 */
static void ocfs2_xa_cleanup_value_truncate(struct ocfs2_xa_loc *loc,
                                            const char *what,
                                            unsigned int orig_clusters)
{
        unsigned int new_clusters = ocfs2_xa_value_clusters(loc);
        char *nameval_buf = ocfs2_xa_offset_pointer(loc,
                                le16_to_cpu(loc->xl_entry->xe_name_offset));

        if (new_clusters < orig_clusters) {
                mlog(ML_ERROR,
                     "Partial truncate while %s xattr %.*s.  Leaking "
                     "%u clusters and removing the entry\n",
                     what, loc->xl_entry->xe_name_len, nameval_buf,
                     orig_clusters - new_clusters);
                ocfs2_xa_remove_entry(loc);
        } else if (!orig_clusters) {
                mlog(ML_ERROR,
                     "Unable to allocate an external value for xattr "
                     "%.*s safely.  Leaking %u clusters and removing the "
                     "entry\n",

                     loc->xl_entry->xe_name_len, nameval_buf,
                     new_clusters - orig_clusters);
                ocfs2_xa_remove_entry(loc);
        } else if (new_clusters > orig_clusters)
                mlog(ML_ERROR,
                     "Unable to grow xattr %.*s safely.  %u new clusters "
                     "have been added, but the value will not be "
                     "modified\n",
                     loc->xl_entry->xe_name_len, nameval_buf,
                     new_clusters - orig_clusters);
}

static int ocfs2_xa_remove(struct ocfs2_xa_loc *loc,
                           struct ocfs2_xattr_set_ctxt *ctxt)
{
        int rc = 0;
        unsigned int orig_clusters;

        if (!ocfs2_xattr_is_local(loc->xl_entry)) {
                orig_clusters = ocfs2_xa_value_clusters(loc);
                rc = ocfs2_xa_value_truncate(loc, 0, ctxt);
                if (rc) {
                        mlog_errno(rc);
                        /*
                         * Since this is remove, we can return 0 if
                         * ocfs2_xa_cleanup_value_truncate() is going to
                         * wipe the entry anyway.  So we check the
                         * cluster count as well.
                         */
                        if (orig_clusters != ocfs2_xa_value_clusters(loc))
                                rc = 0;
                        ocfs2_xa_cleanup_value_truncate(loc, "removing",
                                                        orig_clusters);
                        if (rc)
                                goto out;
                }
        }

        ocfs2_xa_remove_entry(loc);

out:
        return rc;
}

static void ocfs2_xa_install_value_root(struct ocfs2_xa_loc *loc)
{
        int name_size = OCFS2_XATTR_SIZE(loc->xl_entry->xe_name_len);
        char *nameval_buf;

        nameval_buf = ocfs2_xa_offset_pointer(loc,
                                le16_to_cpu(loc->xl_entry->xe_name_offset));
        memcpy(nameval_buf + name_size, &def_xv, OCFS2_XATTR_ROOT_SIZE);
}

/*
 * Take an existing entry and make it ready for the new value.  This
 * won't allocate space, but it may free space.  It should be ready for
 * ocfs2_xa_prepare_entry() to finish the work.
 */
static int ocfs2_xa_reuse_entry(struct ocfs2_xa_loc *loc,
                                struct ocfs2_xattr_info *xi,
                                struct ocfs2_xattr_set_ctxt *ctxt)
{
        int rc = 0;
        int name_size = OCFS2_XATTR_SIZE(xi->xi_name_len);
        unsigned int orig_clusters;
        char *nameval_buf;
        int xe_local = ocfs2_xattr_is_local(loc->xl_entry);
        int xi_local = xi->xi_value_len <= OCFS2_XATTR_INLINE_SIZE;

        BUG_ON(OCFS2_XATTR_SIZE(loc->xl_entry->xe_name_len) !=
               name_size);

        nameval_buf = ocfs2_xa_offset_pointer(loc,
                                le16_to_cpu(loc->xl_entry->xe_name_offset));
        if (xe_local) {
                memset(nameval_buf + name_size, 0,
                       namevalue_size_xe(loc->xl_entry) - name_size);
                if (!xi_local)
                        ocfs2_xa_install_value_root(loc);
        } else {
                orig_clusters = ocfs2_xa_value_clusters(loc);
                if (xi_local) {
                        rc = ocfs2_xa_value_truncate(loc, 0, ctxt);
                        if (rc < 0)
                                mlog_errno(rc);
                        else
                                memset(nameval_buf + name_size, 0,
                                       namevalue_size_xe(loc->xl_entry) -
                                       name_size);
                } else if (le64_to_cpu(loc->xl_entry->xe_value_size) >
                           xi->xi_value_len) {
                        rc = ocfs2_xa_value_truncate(loc, xi->xi_value_len,
                                                     ctxt);
                        if (rc < 0)
                                mlog_errno(rc);
                }

                if (rc) {
                        ocfs2_xa_cleanup_value_truncate(loc, "reusing",
                                                        orig_clusters);
                        goto out;
                }
        }

        loc->xl_entry->xe_value_size = cpu_to_le64(xi->xi_value_len);
        ocfs2_xattr_set_local(loc->xl_entry, xi_local);

out:
        return rc;
}

/*
 * Prepares loc->xl_entry to receive the new xattr.  This includes
 * properly setting up the name+value pair region.  If loc->xl_entry
 * already exists, it will take care of modifying it appropriately.
 *
 * Note that this modifies the data.  You did journal_access already,
 * right?
 */
static int ocfs2_xa_prepare_entry(struct ocfs2_xa_loc *loc,
                                  struct ocfs2_xattr_info *xi,
                                  u32 name_hash,
                                  struct ocfs2_xattr_set_ctxt *ctxt)
{
        int rc = 0;
        unsigned int orig_clusters;
        __le64 orig_value_size = 0;

        rc = ocfs2_xa_check_space(loc, xi);
        if (rc)
                goto out;

        if (loc->xl_entry) {
                if (ocfs2_xa_can_reuse_entry(loc, xi)) {
                        orig_value_size = loc->xl_entry->xe_value_size;
                        rc = ocfs2_xa_reuse_entry(loc, xi, ctxt);
                        if (rc)
                                goto out;
                        goto alloc_value;
                }

                if (!ocfs2_xattr_is_local(loc->xl_entry)) {
                        orig_clusters = ocfs2_xa_value_clusters(loc);
                        rc = ocfs2_xa_value_truncate(loc, 0, ctxt);
                        if (rc) {
                                mlog_errno(rc);
                                ocfs2_xa_cleanup_value_truncate(loc,
                                                                "overwriting",
                                                                orig_clusters);
                                goto out;
                        }
                }
                ocfs2_xa_wipe_namevalue(loc);
        } else
                ocfs2_xa_add_entry(loc, name_hash);

        /*
         * If we get here, we have a blank entry.  Fill it.  We grow our
         * name+value pair back from the end.
         */
        ocfs2_xa_add_namevalue(loc, xi);
        if (xi->xi_value_len > OCFS2_XATTR_INLINE_SIZE)
                ocfs2_xa_install_value_root(loc);

alloc_value:
        if (xi->xi_value_len > OCFS2_XATTR_INLINE_SIZE) {
                orig_clusters = ocfs2_xa_value_clusters(loc);
                rc = ocfs2_xa_value_truncate(loc, xi->xi_value_len, ctxt);
                if (rc < 0) {
                        ctxt->set_abort = 1;
                        ocfs2_xa_cleanup_value_truncate(loc, "growing",
                                                        orig_clusters);
                        /*
                         * If we were growing an existing value,
                         * ocfs2_xa_cleanup_value_truncate() won't remove
                         * the entry. We need to restore the original value
                         * size.
                         */
                        if (loc->xl_entry) {
                                BUG_ON(!orig_value_size);
                                loc->xl_entry->xe_value_size = orig_value_size;
                        }
                        mlog_errno(rc);
                }
        }

out:
        return rc;
}

/*
 * Store the value portion of the name+value pair.  This will skip
 * values that are stored externally.  Their tree roots were set up
 * by ocfs2_xa_prepare_entry().
 */
static int ocfs2_xa_store_value(struct ocfs2_xa_loc *loc,
                                struct ocfs2_xattr_info *xi,
                                struct ocfs2_xattr_set_ctxt *ctxt)
{
        int rc = 0;
        int nameval_offset = le16_to_cpu(loc->xl_entry->xe_name_offset);
        int name_size = OCFS2_XATTR_SIZE(xi->xi_name_len);
        char *nameval_buf;
        struct ocfs2_xattr_value_buf vb;

        nameval_buf = ocfs2_xa_offset_pointer(loc, nameval_offset);
        if (xi->xi_value_len > OCFS2_XATTR_INLINE_SIZE) {
                ocfs2_xa_fill_value_buf(loc, &vb);
                rc = __ocfs2_xattr_set_value_outside(loc->xl_inode,
                                                     ctxt->handle, &vb,
                                                     xi->xi_value,
                                                     xi->xi_value_len);
        } else
                memcpy(nameval_buf + name_size, xi->xi_value, xi->xi_value_len);

        return rc;
}

static int ocfs2_xa_set(struct ocfs2_xa_loc *loc,
                        struct ocfs2_xattr_info *xi,
                        struct ocfs2_xattr_set_ctxt *ctxt)
{
        int ret;
        u32 name_hash = ocfs2_xattr_name_hash(loc->xl_inode, xi->xi_name,
                                              xi->xi_name_len);

        ret = ocfs2_xa_journal_access(ctxt->handle, loc,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        /*
         * From here on out, everything is going to modify the buffer a
         * little.  Errors are going to leave the xattr header in a
         * sane state.  Thus, even with errors we dirty the sucker.
         */

        /* Don't worry, we are never called with !xi_value and !xl_entry */
        if (!xi->xi_value) {
                ret = ocfs2_xa_remove(loc, ctxt);
                goto out_dirty;
        }

        ret = ocfs2_xa_prepare_entry(loc, xi, name_hash, ctxt);
        if (ret) {
                if (ret != -ENOSPC)
                        mlog_errno(ret);
                goto out_dirty;
        }

        ret = ocfs2_xa_store_value(loc, xi, ctxt);
        if (ret)
                mlog_errno(ret);

out_dirty:
        ocfs2_xa_journal_dirty(ctxt->handle, loc);

out:
        return ret;
}

static void ocfs2_init_dinode_xa_loc(struct ocfs2_xa_loc *loc,
                                     struct inode *inode,
                                     struct buffer_head *bh,
                                     struct ocfs2_xattr_entry *entry)
{
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;

        BUG_ON(!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_XATTR_FL));

        loc->xl_inode = inode;
        loc->xl_ops = &ocfs2_xa_block_loc_ops;
        loc->xl_storage = bh;
        loc->xl_entry = entry;
        loc->xl_size = le16_to_cpu(di->i_xattr_inline_size);
        loc->xl_header =
                (struct ocfs2_xattr_header *)(bh->b_data + bh->b_size -
                                              loc->xl_size);
}

static void ocfs2_init_xattr_block_xa_loc(struct ocfs2_xa_loc *loc,
                                          struct inode *inode,
                                          struct buffer_head *bh,
                                          struct ocfs2_xattr_entry *entry)
{
        struct ocfs2_xattr_block *xb =
                (struct ocfs2_xattr_block *)bh->b_data;

        BUG_ON(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED);

        loc->xl_inode = inode;
        loc->xl_ops = &ocfs2_xa_block_loc_ops;
        loc->xl_storage = bh;
        loc->xl_header = &(xb->xb_attrs.xb_header);
        loc->xl_entry = entry;
        loc->xl_size = bh->b_size - offsetof(struct ocfs2_xattr_block,
                                             xb_attrs.xb_header);
}

static void ocfs2_init_xattr_bucket_xa_loc(struct ocfs2_xa_loc *loc,
                                           struct ocfs2_xattr_bucket *bucket,
                                           struct ocfs2_xattr_entry *entry)
{
        loc->xl_inode = bucket->bu_inode;
        loc->xl_ops = &ocfs2_xa_bucket_loc_ops;
        loc->xl_storage = bucket;
        loc->xl_header = bucket_xh(bucket);
        loc->xl_entry = entry;
        loc->xl_size = OCFS2_XATTR_BUCKET_SIZE;
}

/*
 * In xattr remove, if it is stored outside and refcounted, we may have
 * the chance to split the refcount tree. So need the allocators.
 */
static int ocfs2_lock_xattr_remove_allocators(struct inode *inode,
                                        struct ocfs2_xattr_value_root *xv,
                                        struct ocfs2_caching_info *ref_ci,
                                        struct buffer_head *ref_root_bh,
                                        struct ocfs2_alloc_context **meta_ac,
                                        int *ref_credits)
{
        int ret, meta_add = 0;
        u32 p_cluster, num_clusters;
        unsigned int ext_flags;

        *ref_credits = 0;
        ret = ocfs2_xattr_get_clusters(inode, 0, &p_cluster,
                                       &num_clusters,
                                       &xv->xr_list,
                                       &ext_flags);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        if (!(ext_flags & OCFS2_EXT_REFCOUNTED))
                goto out;

        ret = ocfs2_refcounted_xattr_delete_need(inode, ref_ci,
                                                 ref_root_bh, xv,
                                                 &meta_add, ref_credits);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        ret = ocfs2_reserve_new_metadata_blocks(OCFS2_SB(inode->i_sb),
                                                meta_add, meta_ac);
        if (ret)
                mlog_errno(ret);

out:
        return ret;
}

static int ocfs2_remove_value_outside(struct inode*inode,
                                      struct ocfs2_xattr_value_buf *vb,
                                      struct ocfs2_xattr_header *header,
                                      struct ocfs2_caching_info *ref_ci,
                                      struct buffer_head *ref_root_bh)
{
        int ret = 0, i, ref_credits;
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
        struct ocfs2_xattr_set_ctxt ctxt = { NULL, NULL, };
        void *val;

        ocfs2_init_dealloc_ctxt(&ctxt.dealloc);

        for (i = 0; i < le16_to_cpu(header->xh_count); i++) {
                struct ocfs2_xattr_entry *entry = &header->xh_entries[i];

                if (ocfs2_xattr_is_local(entry))
                        continue;

                val = (void *)header +
                        le16_to_cpu(entry->xe_name_offset);
                vb->vb_xv = (struct ocfs2_xattr_value_root *)
                        (val + OCFS2_XATTR_SIZE(entry->xe_name_len));

                ret = ocfs2_lock_xattr_remove_allocators(inode, vb->vb_xv,
                                                         ref_ci, ref_root_bh,
                                                         &ctxt.meta_ac,
                                                         &ref_credits);

                ctxt.handle = ocfs2_start_trans(osb, ref_credits +
                                        ocfs2_remove_extent_credits(osb->sb));
                if (IS_ERR(ctxt.handle)) {
                        ret = PTR_ERR(ctxt.handle);
                        mlog_errno(ret);
                        break;
                }

                ret = ocfs2_xattr_value_truncate(inode, vb, 0, &ctxt);

                ocfs2_commit_trans(osb, ctxt.handle);
                if (ctxt.meta_ac) {
                        ocfs2_free_alloc_context(ctxt.meta_ac);
                        ctxt.meta_ac = NULL;
                }

                if (ret < 0) {
                        mlog_errno(ret);
                        break;
                }

        }

        if (ctxt.meta_ac)
                ocfs2_free_alloc_context(ctxt.meta_ac);
        ocfs2_schedule_truncate_log_flush(osb, 1);
        ocfs2_run_deallocs(osb, &ctxt.dealloc);
        return ret;
}

static int ocfs2_xattr_ibody_remove(struct inode *inode,
                                    struct buffer_head *di_bh,
                                    struct ocfs2_caching_info *ref_ci,
                                    struct buffer_head *ref_root_bh)
{

        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        struct ocfs2_xattr_header *header;
        int ret;
        struct ocfs2_xattr_value_buf vb = {
                .vb_bh = di_bh,
                .vb_access = ocfs2_journal_access_di,
        };

        header = (struct ocfs2_xattr_header *)
                 ((void *)di + inode->i_sb->s_blocksize -
                 le16_to_cpu(di->i_xattr_inline_size));

        ret = ocfs2_remove_value_outside(inode, &vb, header,
                                         ref_ci, ref_root_bh);

        return ret;
}

struct ocfs2_rm_xattr_bucket_para {
        struct ocfs2_caching_info *ref_ci;
        struct buffer_head *ref_root_bh;
};

static int ocfs2_xattr_block_remove(struct inode *inode,
                                    struct buffer_head *blk_bh,
                                    struct ocfs2_caching_info *ref_ci,
                                    struct buffer_head *ref_root_bh)
{
        struct ocfs2_xattr_block *xb;
        int ret = 0;
        struct ocfs2_xattr_value_buf vb = {
                .vb_bh = blk_bh,
                .vb_access = ocfs2_journal_access_xb,
        };
        struct ocfs2_rm_xattr_bucket_para args = {
                .ref_ci = ref_ci,
                .ref_root_bh = ref_root_bh,
        };

        xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
        if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) {
                struct ocfs2_xattr_header *header = &(xb->xb_attrs.xb_header);
                ret = ocfs2_remove_value_outside(inode, &vb, header,
                                                 ref_ci, ref_root_bh);
        } else
                ret = ocfs2_iterate_xattr_index_block(inode,
                                                blk_bh,
                                                ocfs2_rm_xattr_cluster,
                                                &args);

        return ret;
}

static int ocfs2_xattr_free_block(struct inode *inode,
                                  u64 block,
                                  struct ocfs2_caching_info *ref_ci,
                                  struct buffer_head *ref_root_bh)
{
        struct inode *xb_alloc_inode;
        struct buffer_head *xb_alloc_bh = NULL;
        struct buffer_head *blk_bh = NULL;
        struct ocfs2_xattr_block *xb;
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
        handle_t *handle;
        int ret = 0;
        u64 blk, bg_blkno;
        u16 bit;

        ret = ocfs2_read_xattr_block(inode, block, &blk_bh);
        if (ret < 0) {
                mlog_errno(ret);
                goto out;
        }

        ret = ocfs2_xattr_block_remove(inode, blk_bh, ref_ci, ref_root_bh);
        if (ret < 0) {
                mlog_errno(ret);
                goto out;
        }

        xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
        blk = le64_to_cpu(xb->xb_blkno);
        bit = le16_to_cpu(xb->xb_suballoc_bit);
        if (xb->xb_suballoc_loc)
                bg_blkno = le64_to_cpu(xb->xb_suballoc_loc);
        else
                bg_blkno = ocfs2_which_suballoc_group(blk, bit);

        xb_alloc_inode = ocfs2_get_system_file_inode(osb,
                                EXTENT_ALLOC_SYSTEM_INODE,
                                le16_to_cpu(xb->xb_suballoc_slot));
        if (!xb_alloc_inode) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto out;
        }
        inode_lock(xb_alloc_inode);

        ret = ocfs2_inode_lock(xb_alloc_inode, &xb_alloc_bh, 1);
        if (ret < 0) {
                mlog_errno(ret);
                goto out_mutex;
        }

        handle = ocfs2_start_trans(osb, OCFS2_SUBALLOC_FREE);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
                mlog_errno(ret);
                goto out_unlock;
        }

        ret = ocfs2_free_suballoc_bits(handle, xb_alloc_inode, xb_alloc_bh,
                                       bit, bg_blkno, 1);
        if (ret < 0)
                mlog_errno(ret);

        ocfs2_commit_trans(osb, handle);
out_unlock:
        ocfs2_inode_unlock(xb_alloc_inode, 1);
        brelse(xb_alloc_bh);
out_mutex:
        inode_unlock(xb_alloc_inode);
        iput(xb_alloc_inode);
out:
        brelse(blk_bh);
        return ret;
}

/*
 * ocfs2_xattr_remove()
 *
 * Free extended attribute resources associated with this inode.
 */
int ocfs2_xattr_remove(struct inode *inode, struct buffer_head *di_bh)
{
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        struct ocfs2_refcount_tree *ref_tree = NULL;
        struct buffer_head *ref_root_bh = NULL;
        struct ocfs2_caching_info *ref_ci = NULL;
        handle_t *handle;
        int ret;

        if (!ocfs2_supports_xattr(OCFS2_SB(inode->i_sb)))
                return 0;

        if (!(oi->ip_dyn_features & OCFS2_HAS_XATTR_FL))
                return 0;

        if (ocfs2_is_refcount_inode(inode)) {
                ret = ocfs2_lock_refcount_tree(OCFS2_SB(inode->i_sb),
                                               le64_to_cpu(di->i_refcount_loc),
                                               1, &ref_tree, &ref_root_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }
                ref_ci = &ref_tree->rf_ci;

        }

        if (oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL) {
                ret = ocfs2_xattr_ibody_remove(inode, di_bh,
                                               ref_ci, ref_root_bh);
                if (ret < 0) {
                        mlog_errno(ret);
                        goto out;
                }
        }

        if (di->i_xattr_loc) {
                ret = ocfs2_xattr_free_block(inode,
                                             le64_to_cpu(di->i_xattr_loc),
                                             ref_ci, ref_root_bh);
                if (ret < 0) {
                        mlog_errno(ret);
                        goto out;
                }
        }

        handle = ocfs2_start_trans((OCFS2_SB(inode->i_sb)),
                                   OCFS2_INODE_UPDATE_CREDITS);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
                mlog_errno(ret);
                goto out;
        }
        ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        di->i_xattr_loc = 0;

        spin_lock(&oi->ip_lock);
        oi->ip_dyn_features &= ~(OCFS2_INLINE_XATTR_FL | OCFS2_HAS_XATTR_FL);
        di->i_dyn_features = cpu_to_le16(oi->ip_dyn_features);
        spin_unlock(&oi->ip_lock);
        ocfs2_update_inode_fsync_trans(handle, inode, 0);

        ocfs2_journal_dirty(handle, di_bh);
out_commit:
        ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
out:
        if (ref_tree)
                ocfs2_unlock_refcount_tree(OCFS2_SB(inode->i_sb), ref_tree, 1);
        brelse(ref_root_bh);
        return ret;
}

static int ocfs2_xattr_has_space_inline(struct inode *inode,
                                        struct ocfs2_dinode *di)
{
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        unsigned int xattrsize = OCFS2_SB(inode->i_sb)->s_xattr_inline_size;
        int free;

        if (xattrsize < OCFS2_MIN_XATTR_INLINE_SIZE)
                return 0;

        if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
                struct ocfs2_inline_data *idata = &di->id2.i_data;
                free = le16_to_cpu(idata->id_count) - le64_to_cpu(di->i_size);
        } else if (ocfs2_inode_is_fast_symlink(inode)) {
                free = ocfs2_fast_symlink_chars(inode->i_sb) -
                        le64_to_cpu(di->i_size);
        } else {
                struct ocfs2_extent_list *el = &di->id2.i_list;
                free = (le16_to_cpu(el->l_count) -
                        le16_to_cpu(el->l_next_free_rec)) *
                        sizeof(struct ocfs2_extent_rec);
        }
        if (free >= xattrsize)
                return 1;

        return 0;
}

/*
 * ocfs2_xattr_ibody_find()
 *
 * Find extended attribute in inode block and
 * fill search info into struct ocfs2_xattr_search.
 */
static int ocfs2_xattr_ibody_find(struct inode *inode,
                                  int name_index,
                                  const char *name,
                                  struct ocfs2_xattr_search *xs)
{
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)xs->inode_bh->b_data;
        int ret;
        int has_space = 0;

        if (inode->i_sb->s_blocksize == OCFS2_MIN_BLOCKSIZE)
                return 0;

        if (!(oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL)) {
                down_read(&oi->ip_alloc_sem);
                has_space = ocfs2_xattr_has_space_inline(inode, di);
                up_read(&oi->ip_alloc_sem);
                if (!has_space)
                        return 0;
        }

        xs->xattr_bh = xs->inode_bh;
        xs->end = (void *)di + inode->i_sb->s_blocksize;
        if (oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL)
                xs->header = (struct ocfs2_xattr_header *)
                        (xs->end - le16_to_cpu(di->i_xattr_inline_size));
        else
                xs->header = (struct ocfs2_xattr_header *)
                        (xs->end - OCFS2_SB(inode->i_sb)->s_xattr_inline_size);
        xs->base = (void *)xs->header;
        xs->here = xs->header->xh_entries;

        /* Find the named attribute. */
        if (oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL) {
                ret = ocfs2_xattr_find_entry(name_index, name, xs);
                if (ret && ret != -ENODATA)
                        return ret;
                xs->not_found = ret;
        }

        return 0;
}

static int ocfs2_xattr_ibody_init(struct inode *inode,
                                  struct buffer_head *di_bh,
                                  struct ocfs2_xattr_set_ctxt *ctxt)
{
        int ret;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
        unsigned int xattrsize = osb->s_xattr_inline_size;

        if (!ocfs2_xattr_has_space_inline(inode, di)) {
                ret = -ENOSPC;
                goto out;
        }

        ret = ocfs2_journal_access_di(ctxt->handle, INODE_CACHE(inode), di_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        /*
         * Adjust extent record count or inline data size
         * to reserve space for extended attribute.
         */
        if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
                struct ocfs2_inline_data *idata = &di->id2.i_data;
                le16_add_cpu(&idata->id_count, -xattrsize);
        } else if (!(ocfs2_inode_is_fast_symlink(inode))) {
                struct ocfs2_extent_list *el = &di->id2.i_list;
                le16_add_cpu(&el->l_count, -(xattrsize /
                                             sizeof(struct ocfs2_extent_rec)));
        }
        di->i_xattr_inline_size = cpu_to_le16(xattrsize);

        spin_lock(&oi->ip_lock);
        oi->ip_dyn_features |= OCFS2_INLINE_XATTR_FL|OCFS2_HAS_XATTR_FL;
        di->i_dyn_features = cpu_to_le16(oi->ip_dyn_features);
        spin_unlock(&oi->ip_lock);

        ocfs2_journal_dirty(ctxt->handle, di_bh);

out:
        return ret;
}

/*
 * ocfs2_xattr_ibody_set()
 *
 * Set, replace or remove an extended attribute into inode block.
 *
 */
static int ocfs2_xattr_ibody_set(struct inode *inode,
                                 struct ocfs2_xattr_info *xi,
                                 struct ocfs2_xattr_search *xs,
                                 struct ocfs2_xattr_set_ctxt *ctxt)
{
        int ret;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_xa_loc loc;

        if (inode->i_sb->s_blocksize == OCFS2_MIN_BLOCKSIZE)
                return -ENOSPC;

        down_write(&oi->ip_alloc_sem);
        if (!(oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL)) {
                ret = ocfs2_xattr_ibody_init(inode, xs->inode_bh, ctxt);
                if (ret) {
                        if (ret != -ENOSPC)
                                mlog_errno(ret);
                        goto out;
                }
        }

        ocfs2_init_dinode_xa_loc(&loc, inode, xs->inode_bh,
                                 xs->not_found ? NULL : xs->here);
        ret = ocfs2_xa_set(&loc, xi, ctxt);
        if (ret) {
                if (ret != -ENOSPC)
                        mlog_errno(ret);
                goto out;
        }
        xs->here = loc.xl_entry;

out:
        up_write(&oi->ip_alloc_sem);

        return ret;
}

/*
 * ocfs2_xattr_block_find()
 *
 * Find extended attribute in external block and
 * fill search info into struct ocfs2_xattr_search.
 */
static int ocfs2_xattr_block_find(struct inode *inode,
                                  int name_index,
                                  const char *name,
                                  struct ocfs2_xattr_search *xs)
{
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)xs->inode_bh->b_data;
        struct buffer_head *blk_bh = NULL;
        struct ocfs2_xattr_block *xb;
        int ret = 0;

        if (!di->i_xattr_loc)
                return ret;

        ret = ocfs2_read_xattr_block(inode, le64_to_cpu(di->i_xattr_loc),
                                     &blk_bh);
        if (ret < 0) {
                mlog_errno(ret);
                return ret;
        }

        xs->xattr_bh = blk_bh;
        xb = (struct ocfs2_xattr_block *)blk_bh->b_data;

        if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) {
                xs->header = &xb->xb_attrs.xb_header;
                xs->base = (void *)xs->header;
                xs->end = (void *)(blk_bh->b_data) + blk_bh->b_size;
                xs->here = xs->header->xh_entries;

                ret = ocfs2_xattr_find_entry(name_index, name, xs);
        } else
                ret = ocfs2_xattr_index_block_find(inode, blk_bh,
                                                   name_index,
                                                   name, xs);

        if (ret && ret != -ENODATA) {
                xs->xattr_bh = NULL;
                goto cleanup;
        }
        xs->not_found = ret;
        return 0;
cleanup:
        brelse(blk_bh);

        return ret;
}

static int ocfs2_create_xattr_block(struct inode *inode,
                                    struct buffer_head *inode_bh,
                                    struct ocfs2_xattr_set_ctxt *ctxt,
                                    int indexed,
                                    struct buffer_head **ret_bh)
{
        int ret;
        u16 suballoc_bit_start;
        u32 num_got;
        u64 suballoc_loc, first_blkno;
        struct ocfs2_dinode *di =  (struct ocfs2_dinode *)inode_bh->b_data;
        struct buffer_head *new_bh = NULL;
        struct ocfs2_xattr_block *xblk;

        ret = ocfs2_journal_access_di(ctxt->handle, INODE_CACHE(inode),
                                      inode_bh, OCFS2_JOURNAL_ACCESS_CREATE);
        if (ret < 0) {
                mlog_errno(ret);
                goto end;
        }

        ret = ocfs2_claim_metadata(ctxt->handle, ctxt->meta_ac, 1,
                                   &suballoc_loc, &suballoc_bit_start,
                                   &num_got, &first_blkno);
        if (ret < 0) {
                mlog_errno(ret);
                goto end;
        }

        new_bh = sb_getblk(inode->i_sb, first_blkno);
        if (!new_bh) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto end;
        }

        ocfs2_set_new_buffer_uptodate(INODE_CACHE(inode), new_bh);

        ret = ocfs2_journal_access_xb(ctxt->handle, INODE_CACHE(inode),
                                      new_bh,
                                      OCFS2_JOURNAL_ACCESS_CREATE);
        if (ret < 0) {
                mlog_errno(ret);
                goto end;
        }

        /* Initialize ocfs2_xattr_block */
        xblk = (struct ocfs2_xattr_block *)new_bh->b_data;
        memset(xblk, 0, inode->i_sb->s_blocksize);
        strcpy((void *)xblk, OCFS2_XATTR_BLOCK_SIGNATURE);
        xblk->xb_suballoc_slot = cpu_to_le16(ctxt->meta_ac->ac_alloc_slot);
        xblk->xb_suballoc_loc = cpu_to_le64(suballoc_loc);
        xblk->xb_suballoc_bit = cpu_to_le16(suballoc_bit_start);
        xblk->xb_fs_generation =
                cpu_to_le32(OCFS2_SB(inode->i_sb)->fs_generation);
        xblk->xb_blkno = cpu_to_le64(first_blkno);
        if (indexed) {
                struct ocfs2_xattr_tree_root *xr = &xblk->xb_attrs.xb_root;
                xr->xt_clusters = cpu_to_le32(1);
                xr->xt_last_eb_blk = 0;
                xr->xt_list.l_tree_depth = 0;
                xr->xt_list.l_count = cpu_to_le16(
                                        ocfs2_xattr_recs_per_xb(inode->i_sb));
                xr->xt_list.l_next_free_rec = cpu_to_le16(1);
                xblk->xb_flags = cpu_to_le16(OCFS2_XATTR_INDEXED);
        }
        ocfs2_journal_dirty(ctxt->handle, new_bh);

        /* Add it to the inode */
        di->i_xattr_loc = cpu_to_le64(first_blkno);

        spin_lock(&OCFS2_I(inode)->ip_lock);
        OCFS2_I(inode)->ip_dyn_features |= OCFS2_HAS_XATTR_FL;
        di->i_dyn_features = cpu_to_le16(OCFS2_I(inode)->ip_dyn_features);
        spin_unlock(&OCFS2_I(inode)->ip_lock);

        ocfs2_journal_dirty(ctxt->handle, inode_bh);

        *ret_bh = new_bh;
        new_bh = NULL;

end:
        brelse(new_bh);
        return ret;
}

/*
 * ocfs2_xattr_block_set()
 *
 * Set, replace or remove an extended attribute into external block.
 *
 */
static int ocfs2_xattr_block_set(struct inode *inode,
                                 struct ocfs2_xattr_info *xi,
                                 struct ocfs2_xattr_search *xs,
                                 struct ocfs2_xattr_set_ctxt *ctxt)
{
        struct buffer_head *new_bh = NULL;
        struct ocfs2_xattr_block *xblk = NULL;
        int ret;
        struct ocfs2_xa_loc loc;

        if (!xs->xattr_bh) {
                ret = ocfs2_create_xattr_block(inode, xs->inode_bh, ctxt,
                                               0, &new_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto end;
                }

                xs->xattr_bh = new_bh;
                xblk = (struct ocfs2_xattr_block *)xs->xattr_bh->b_data;
                xs->header = &xblk->xb_attrs.xb_header;
                xs->base = (void *)xs->header;
                xs->end = (void *)xblk + inode->i_sb->s_blocksize;
                xs->here = xs->header->xh_entries;
        } else
                xblk = (struct ocfs2_xattr_block *)xs->xattr_bh->b_data;

        if (!(le16_to_cpu(xblk->xb_flags) & OCFS2_XATTR_INDEXED)) {
                ocfs2_init_xattr_block_xa_loc(&loc, inode, xs->xattr_bh,
                                              xs->not_found ? NULL : xs->here);

                ret = ocfs2_xa_set(&loc, xi, ctxt);
                if (!ret)
                        xs->here = loc.xl_entry;
                else if ((ret != -ENOSPC) || ctxt->set_abort)
                        goto end;
                else {
                        ret = ocfs2_xattr_create_index_block(inode, xs, ctxt);
                        if (ret)
                                goto end;
                }
        }

        if (le16_to_cpu(xblk->xb_flags) & OCFS2_XATTR_INDEXED)
                ret = ocfs2_xattr_set_entry_index_block(inode, xi, xs, ctxt);

end:
        return ret;
}

/* Check whether the new xattr can be inserted into the inode. */