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 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
  */
 
 /*
  * Implements Extendible Hashing as described in:
  *   "Extendible Hashing" by Fagin, et al in
  *     __ACM Trans. on Database Systems__, Sept 1979.
  *
  *
  * Here's the layout of dirents which is essentially the same as that of ext2
  * within a single block. The field de_name_len is the number of bytes
  * actually required for the name (no null terminator). The field de_rec_len
  * is the number of bytes allocated to the dirent. The offset of the next
  * dirent in the block is (dirent + dirent->de_rec_len). When a dirent is
  * deleted, the preceding dirent inherits its allocated space, ie
  * prev->de_rec_len += deleted->de_rec_len. Since the next dirent is obtained
  * by adding de_rec_len to the current dirent, this essentially causes the
  * deleted dirent to get jumped over when iterating through all the dirents.
  *
  * When deleting the first dirent in a block, there is no previous dirent so
  * the field de_ino is set to zero to designate it as deleted. When allocating
  * a dirent, gfs2_dirent_alloc iterates through the dirents in a block. If the
  * first dirent has (de_ino == 0) and de_rec_len is large enough, this first
  * dirent is allocated. Otherwise it must go through all the 'used' dirents
  * searching for one in which the amount of total space minus the amount of
  * used space will provide enough space for the new dirent.
  *
  * There are two types of blocks in which dirents reside. In a stuffed dinode,
  * the dirents begin at offset sizeof(struct gfs2_dinode) from the beginning of
  * the block.  In leaves, they begin at offset sizeof(struct gfs2_leaf) from the
  * beginning of the leaf block. The dirents reside in leaves when
  *
  * dip->i_diskflags & GFS2_DIF_EXHASH is true
  *
  * Otherwise, the dirents are "linear", within a single stuffed dinode block.
  *
  * When the dirents are in leaves, the actual contents of the directory file are
  * used as an array of 64-bit block pointers pointing to the leaf blocks. The
  * dirents are NOT in the directory file itself. There can be more than one
  * block pointer in the array that points to the same leaf. In fact, when a
  * directory is first converted from linear to exhash, all of the pointers
  * point to the same leaf.
  *
  * When a leaf is completely full, the size of the hash table can be
  * doubled unless it is already at the maximum size which is hard coded into
  * GFS2_DIR_MAX_DEPTH. After that, leaves are chained together in a linked list,
  * but never before the maximum hash table size has been reached.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/buffer_head.h>
 #include <linux/sort.h>
 #include <linux/gfs2_ondisk.h>
 #include <linux/crc32.h>
 #include <linux/vmalloc.h>
 #include <linux/bio.h>
 
 #include "gfs2.h"
 #include "incore.h"
 #include "dir.h"
 #include "glock.h"
 #include "inode.h"
 #include "meta_io.h"
 #include "quota.h"
 #include "rgrp.h"
 #include "trans.h"
 #include "bmap.h"
 #include "util.h"
 
 #define MAX_RA_BLOCKS 32 /* max read-ahead blocks */
 
 #define gfs2_disk_hash2offset(h) (((u64)(h)) >> 1)
 #define gfs2_dir_offset2hash(p) ((u32)(((u64)(p)) << 1))
 #define GFS2_HASH_INDEX_MASK 0xffffc000
 #define GFS2_USE_HASH_FLAG 0x2000
 
 struct qstr gfs2_qdot __read_mostly;
 struct qstr gfs2_qdotdot __read_mostly;
 
 typedef int (*gfs2_dscan_t)(const struct gfs2_dirent *dent,
                 const struct qstr *name, void *opaque);
 
 int gfs2_dir_get_new_buffer(struct gfs2_inode *ip, u64 block,
                 struct buffer_head **bhp)
 {
     struct buffer_head *bh;
 
     bh = gfs2_meta_new(ip->i_gl, block);
     gfs2_trans_add_meta(ip->i_gl, bh);
     gfs2_metatype_set(bh, GFS2_METATYPE_JD, GFS2_FORMAT_JD);
     gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
     *bhp = bh;
     return 0;
 }
 
 static int gfs2_dir_get_existing_buffer(struct gfs2_inode *ip, u64 block,
                     struct buffer_head **bhp)
 {
     struct buffer_head *bh;
     int error;
 
     error = gfs2_meta_read(ip->i_gl, block, DIO_WAIT, 0, &bh);
     if (error)
         return error;
     if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh, GFS2_METATYPE_JD)) {
         brelse(bh);
         return -EIO;
     }
     *bhp = bh;
     return 0;
 }
 
 static int gfs2_dir_write_stuffed(struct gfs2_inode *ip, const char *buf,
                   unsigned int offset, unsigned int size)
 {
     struct buffer_head *dibh;
     int error;
 
     error = gfs2_meta_inode_buffer(ip, &dibh);
     if (error)
         return error;
 
     gfs2_trans_add_meta(ip->i_gl, dibh);
     memcpy(dibh->b_data + offset + sizeof(struct gfs2_dinode), buf, size);
     if (ip->i_inode.i_size < offset + size)
         i_size_write(&ip->i_inode, offset + size);
     ip->i_inode.i_mtime = ip->i_inode.i_ctime = current_time(&ip->i_inode);
     gfs2_dinode_out(ip, dibh->b_data);
 
     brelse(dibh);
 
     return size;
 }
 
 
 
 /**
  * gfs2_dir_write_data - Write directory information to the inode
  * @ip: The GFS2 inode
  * @buf: The buffer containing information to be written
  * @offset: The file offset to start writing at
  * @size: The amount of data to write
  *
  * Returns: The number of bytes correctly written or error code
  */
 static int gfs2_dir_write_data(struct gfs2_inode *ip, const char *buf,
                    u64 offset, unsigned int size)
 {
     struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
     struct buffer_head *dibh;
     u64 lblock, dblock;
     u32 extlen = 0;
     unsigned int o;
     int copied = 0;
     int error = 0;
     bool new = false;
 
     if (!size)
         return 0;
 
     if (gfs2_is_stuffed(ip) && offset + size <= gfs2_max_stuffed_size(ip))
         return gfs2_dir_write_stuffed(ip, buf, (unsigned int)offset,
                           size);
 
     if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip)))
         return -EINVAL;
 
     if (gfs2_is_stuffed(ip)) {
         error = gfs2_unstuff_dinode(ip);
         if (error)
             return error;
     }
 
     lblock = offset;
     o = do_div(lblock, sdp->sd_jbsize) + sizeof(struct gfs2_meta_header);
 
     while (copied < size) {
         unsigned int amount;
         struct buffer_head *bh;
 
         amount = size - copied;
         if (amount > sdp->sd_sb.sb_bsize - o)
             amount = sdp->sd_sb.sb_bsize - o;
 
         if (!extlen) {
             extlen = 1;
             error = gfs2_alloc_extent(&ip->i_inode, lblock, &dblock,
                           &extlen, &new);
             if (error)
                 goto fail;
             error = -EIO;
             if (gfs2_assert_withdraw(sdp, dblock))
                 goto fail;
         }
 
         if (amount == sdp->sd_jbsize || new)
             error = gfs2_dir_get_new_buffer(ip, dblock, &bh);
         else
             error = gfs2_dir_get_existing_buffer(ip, dblock, &bh);
 
         if (error)
             goto fail;
 
         gfs2_trans_add_meta(ip->i_gl, bh);
         memcpy(bh->b_data + o, buf, amount);
         brelse(bh);
 
         buf += amount;
         copied += amount;
         lblock++;
         dblock++;
         extlen--;
 
         o = sizeof(struct gfs2_meta_header);
     }
 
 out:
     error = gfs2_meta_inode_buffer(ip, &dibh);
     if (error)
         return error;
 
     if (ip->i_inode.i_size < offset + copied)
         i_size_write(&ip->i_inode, offset + copied);
     ip->i_inode.i_mtime = ip->i_inode.i_ctime = current_time(&ip->i_inode);
 
     gfs2_trans_add_meta(ip->i_gl, dibh);
     gfs2_dinode_out(ip, dibh->b_data);
     brelse(dibh);
 
     return copied;
 fail:
     if (copied)
         goto out;
     return error;
 }
 
 static int gfs2_dir_read_stuffed(struct gfs2_inode *ip, __be64 *buf,
                  unsigned int size)
 {
     struct buffer_head *dibh;
     int error;
 
     error = gfs2_meta_inode_buffer(ip, &dibh);
     if (!error) {
         memcpy(buf, dibh->b_data + sizeof(struct gfs2_dinode), size);
         brelse(dibh);
     }
 
     return (error) ? error : size;
 }
 
 
 /**
  * gfs2_dir_read_data - Read a data from a directory inode
  * @ip: The GFS2 Inode
  * @buf: The buffer to place result into
  * @size: Amount of data to transfer
  *
  * Returns: The amount of data actually copied or the error
  */
 static int gfs2_dir_read_data(struct gfs2_inode *ip, __be64 *buf,
                   unsigned int size)
 {
     struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
     u64 lblock, dblock;
     u32 extlen = 0;
     unsigned int o;
     int copied = 0;
     int error = 0;
 
     if (gfs2_is_stuffed(ip))
         return gfs2_dir_read_stuffed(ip, buf, size);
 
     if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip)))
         return -EINVAL;
 
     lblock = 0;
     o = do_div(lblock, sdp->sd_jbsize) + sizeof(struct gfs2_meta_header);
 
     while (copied < size) {
         unsigned int amount;
         struct buffer_head *bh;
 
         amount = size - copied;
         if (amount > sdp->sd_sb.sb_bsize - o)
             amount = sdp->sd_sb.sb_bsize - o;
 
         if (!extlen) {
             extlen = 32;
             error = gfs2_get_extent(&ip->i_inode, lblock,
                         &dblock, &extlen);
             if (error || !dblock)
                 goto fail;
             BUG_ON(extlen < 1);
             bh = gfs2_meta_ra(ip->i_gl, dblock, extlen);
         } else {
             error = gfs2_meta_read(ip->i_gl, dblock, DIO_WAIT, 0, &bh);
             if (error)
                 goto fail;
         }
         error = gfs2_metatype_check(sdp, bh, GFS2_METATYPE_JD);
         if (error) {
             brelse(bh);
             goto fail;
         }
         dblock++;
         extlen--;
         memcpy(buf, bh->b_data + o, amount);
         brelse(bh);
         buf += (amount/sizeof(__be64));
         copied += amount;
         lblock++;
         o = sizeof(struct gfs2_meta_header);
     }
 
     return copied;
 fail:
     return (copied) ? copied : error;
 }
 
 /**
  * gfs2_dir_get_hash_table - Get pointer to the dir hash table
  * @ip: The inode in question
  *
  * Returns: The hash table or an error
  */
 
 static __be64 *gfs2_dir_get_hash_table(struct gfs2_inode *ip)
 {
     struct inode *inode = &ip->i_inode;
     int ret;
     u32 hsize;
     __be64 *hc;
 
     BUG_ON(!(ip->i_diskflags & GFS2_DIF_EXHASH));
 
     hc = ip->i_hash_cache;
     if (hc)
         return hc;
 
     hsize = BIT(ip->i_depth);
     hsize *= sizeof(__be64);
     if (hsize != i_size_read(&ip->i_inode)) {
         gfs2_consist_inode(ip);
         return ERR_PTR(-EIO);
     }
 
     hc = kmalloc(hsize, GFP_NOFS | __GFP_NOWARN);
     if (hc == NULL)
         hc = __vmalloc(hsize, GFP_NOFS);
 
     if (hc == NULL)
         return ERR_PTR(-ENOMEM);
 
     ret = gfs2_dir_read_data(ip, hc, hsize);
     if (ret < 0) {
         kvfree(hc);
         return ERR_PTR(ret);
     }
 
     spin_lock(&inode->i_lock);
     if (likely(!ip->i_hash_cache)) {
         ip->i_hash_cache = hc;
         hc = NULL;
     }
     spin_unlock(&inode->i_lock);
     kvfree(hc);
 
     return ip->i_hash_cache;
 }
 
 /**
  * gfs2_dir_hash_inval - Invalidate dir hash
  * @ip: The directory inode
  *
  * Must be called with an exclusive glock, or during glock invalidation.
  */
 void gfs2_dir_hash_inval(struct gfs2_inode *ip)
 {
     __be64 *hc;
 
     spin_lock(&ip->i_inode.i_lock);
     hc = ip->i_hash_cache;
     ip->i_hash_cache = NULL;
     spin_unlock(&ip->i_inode.i_lock);
 
     kvfree(hc);
 }
 
 static inline int gfs2_dirent_sentinel(const struct gfs2_dirent *dent)
 {
     return dent->de_inum.no_addr == 0 || dent->de_inum.no_formal_ino == 0;
 }
 
 static inline int __gfs2_dirent_find(const struct gfs2_dirent *dent,
                      const struct qstr *name, int ret)
 {
     if (!gfs2_dirent_sentinel(dent) &&
         be32_to_cpu(dent->de_hash) == name->hash &&
         be16_to_cpu(dent->de_name_len) == name->len &&
         memcmp(dent+1, name->name, name->len) == 0)
         return ret;
     return 0;
 }
 
 static int gfs2_dirent_find(const struct gfs2_dirent *dent,
                 const struct qstr *name,
                 void *opaque)
 {
     return __gfs2_dirent_find(dent, name, 1);
 }
 
 static int gfs2_dirent_prev(const struct gfs2_dirent *dent,
                 const struct qstr *name,
                 void *opaque)
 {
     return __gfs2_dirent_find(dent, name, 2);
 }
 
 /*
  * name->name holds ptr to start of block.
  * name->len holds size of block.
  */
 static int gfs2_dirent_last(const struct gfs2_dirent *dent,
                 const struct qstr *name,
                 void *opaque)
 {
     const char *start = name->name;
     const char *end = (const char *)dent + be16_to_cpu(dent->de_rec_len);
     if (name->len == (end - start))
         return 1;
     return 0;
 }
 
 /* Look for the dirent that contains the offset specified in data. Once we
  * find that dirent, there must be space available there for the new dirent */
 static int gfs2_dirent_find_offset(const struct gfs2_dirent *dent,
                   const struct qstr *name,
                   void *ptr)
 {
     unsigned required = GFS2_DIRENT_SIZE(name->len);
     unsigned actual = GFS2_DIRENT_SIZE(be16_to_cpu(dent->de_name_len));
     unsigned totlen = be16_to_cpu(dent->de_rec_len);
 
     if (ptr < (void *)dent || ptr >= (void *)dent + totlen)
         return 0;
     if (gfs2_dirent_sentinel(dent))
         actual = 0;
     if (ptr < (void *)dent + actual)
         return -1;
     if ((void *)dent + totlen >= ptr + required)
         return 1;
     return -1;
 }
 
 static int gfs2_dirent_find_space(const struct gfs2_dirent *dent,
                   const struct qstr *name,
                   void *opaque)
 {
     unsigned required = GFS2_DIRENT_SIZE(name->len);
     unsigned actual = GFS2_DIRENT_SIZE(be16_to_cpu(dent->de_name_len));
     unsigned totlen = be16_to_cpu(dent->de_rec_len);
 
     if (gfs2_dirent_sentinel(dent))
         actual = 0;
     if (totlen - actual >= required)
         return 1;
     return 0;
 }
 
 struct dirent_gather {
     const struct gfs2_dirent **pdent;
     unsigned offset;
 };
 
 static int gfs2_dirent_gather(const struct gfs2_dirent *dent,
                   const struct qstr *name,
                   void *opaque)
 {
     struct dirent_gather *g = opaque;
     if (!gfs2_dirent_sentinel(dent)) {
         g->pdent[g->offset++] = dent;
     }
     return 0;
 }
 
 /*
  * Other possible things to check:
  * - Inode located within filesystem size (and on valid block)
  * - Valid directory entry type
  * Not sure how heavy-weight we want to make this... could also check
  * hash is correct for example, but that would take a lot of extra time.
  * For now the most important thing is to check that the various sizes
  * are correct.
  */
 static int gfs2_check_dirent(struct gfs2_sbd *sdp,
                  struct gfs2_dirent *dent, unsigned int offset,
                  unsigned int size, unsigned int len, int first)
 {
     const char *msg = "gfs2_dirent too small";
     if (unlikely(size < sizeof(struct gfs2_dirent)))
         goto error;
     msg = "gfs2_dirent misaligned";
     if (unlikely(offset & 0x7))
         goto error;
     msg = "gfs2_dirent points beyond end of block";
     if (unlikely(offset + size > len))
         goto error;
     msg = "zero inode number";
     if (unlikely(!first && gfs2_dirent_sentinel(dent)))
         goto error;
     msg = "name length is greater than space in dirent";
     if (!gfs2_dirent_sentinel(dent) &&
         unlikely(sizeof(struct gfs2_dirent)+be16_to_cpu(dent->de_name_len) >
              size))
         goto error;
     return 0;
 error:
     fs_warn(sdp, "%s: %s (%s)\n",
         __func__, msg, first ? "first in block" : "not first in block");
     return -EIO;
 }
 
 static int gfs2_dirent_offset(struct gfs2_sbd *sdp, const void *buf)
 {
     const struct gfs2_meta_header *h = buf;
     int offset;
 
     BUG_ON(buf == NULL);
 
     switch(be32_to_cpu(h->mh_type)) {
     case GFS2_METATYPE_LF:
         offset = sizeof(struct gfs2_leaf);
         break;
     case GFS2_METATYPE_DI:
         offset = sizeof(struct gfs2_dinode);
         break;
     default:
         goto wrong_type;
     }
     return offset;
 wrong_type:
     fs_warn(sdp, "%s: wrong block type %u\n", __func__,
         be32_to_cpu(h->mh_type));
     return -1;
 }
 
 static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode, void *buf,
                         unsigned int len, gfs2_dscan_t scan,
                         const struct qstr *name,
                         void *opaque)
 {
     struct gfs2_dirent *dent, *prev;
     unsigned offset;
     unsigned size;
     int ret = 0;
 
     ret = gfs2_dirent_offset(GFS2_SB(inode), buf);
     if (ret < 0)
         goto consist_inode;
 
     offset = ret;
     prev = NULL;
     dent = buf + offset;
     size = be16_to_cpu(dent->de_rec_len);
     if (gfs2_check_dirent(GFS2_SB(inode), dent, offset, size, len, 1))
         goto consist_inode;
     do {
         ret = scan(dent, name, opaque);
         if (ret)
             break;
         offset += size;
         if (offset == len)
             break;
         prev = dent;
         dent = buf + offset;
         size = be16_to_cpu(dent->de_rec_len);
         if (gfs2_check_dirent(GFS2_SB(inode), dent, offset, size,
                       len, 0))
             goto consist_inode;
     } while(1);
 
     switch(ret) {
     case 0:
         return NULL;
     case 1:
         return dent;
     case 2:
         return prev ? prev : dent;
     default:
         BUG_ON(ret > 0);
         return ERR_PTR(ret);
     }
 
 consist_inode:
     gfs2_consist_inode(GFS2_I(inode));
     return ERR_PTR(-EIO);
 }
 
 static int dirent_check_reclen(struct gfs2_inode *dip,
                    const struct gfs2_dirent *d, const void *end_p)
 {
     const void *ptr = d;
     u16 rec_len = be16_to_cpu(d->de_rec_len);
 
     if (unlikely(rec_len < sizeof(struct gfs2_dirent)))
         goto broken;
     ptr += rec_len;
     if (ptr < end_p)
         return rec_len;
     if (ptr == end_p)
         return -ENOENT;
 broken:
     gfs2_consist_inode(dip);
     return -EIO;
 }
 
 /**
  * dirent_next - Next dirent
  * @dip: the directory
  * @bh: The buffer
  * @dent: Pointer to list of dirents
  *
  * Returns: 0 on success, error code otherwise
  */
 
 static int dirent_next(struct gfs2_inode *dip, struct buffer_head *bh,
                struct gfs2_dirent **dent)
 {
     struct gfs2_dirent *cur = *dent, *tmp;
     char *bh_end = bh->b_data + bh->b_size;
     int ret;
 
     ret = dirent_check_reclen(dip, cur, bh_end);
     if (ret < 0)
         return ret;
 
     tmp = (void *)cur + ret;
     ret = dirent_check_reclen(dip, tmp, bh_end);
     if (ret == -EIO)
         return ret;
 
         /* Only the first dent could ever have de_inum.no_addr == 0 */
     if (gfs2_dirent_sentinel(tmp)) {
         gfs2_consist_inode(dip);
         return -EIO;
     }
 
     *dent = tmp;
     return 0;
 }
 
 /**
  * dirent_del - Delete a dirent
  * @dip: The GFS2 inode
  * @bh: The buffer
  * @prev: The previous dirent
  * @cur: The current dirent
  *
  */
 
 static void dirent_del(struct gfs2_inode *dip, struct buffer_head *bh,
                struct gfs2_dirent *prev, struct gfs2_dirent *cur)
 {
     u16 cur_rec_len, prev_rec_len;
 
     if (gfs2_dirent_sentinel(cur)) {
         gfs2_consist_inode(dip);
         return;
     }
 
     gfs2_trans_add_meta(dip->i_gl, bh);
 
     /* If there is no prev entry, this is the first entry in the block.
        The de_rec_len is already as big as it needs to be.  Just zero
        out the inode number and return.  */
 
     if (!prev) {
         cur->de_inum.no_addr = 0;
         cur->de_inum.no_formal_ino = 0;
         return;
     }
 
     /*  Combine this dentry with the previous one.  */
 
     prev_rec_len = be16_to_cpu(prev->de_rec_len);
     cur_rec_len = be16_to_cpu(cur->de_rec_len);
 
     if ((char *)prev + prev_rec_len != (char *)cur)
         gfs2_consist_inode(dip);
     if ((char *)cur + cur_rec_len > bh->b_data + bh->b_size)
         gfs2_consist_inode(dip);
 
     prev_rec_len += cur_rec_len;
     prev->de_rec_len = cpu_to_be16(prev_rec_len);
 }
 
 
 static struct gfs2_dirent *do_init_dirent(struct inode *inode,
                       struct gfs2_dirent *dent,
                       const struct qstr *name,
                       struct buffer_head *bh,
                       unsigned offset)
 {
     struct gfs2_inode *ip = GFS2_I(inode);
     struct gfs2_dirent *ndent;
     unsigned totlen;
 
     totlen = be16_to_cpu(dent->de_rec_len);
     BUG_ON(offset + name->len > totlen);
     gfs2_trans_add_meta(ip->i_gl, bh);
     ndent = (struct gfs2_dirent *)((char *)dent + offset);
     dent->de_rec_len = cpu_to_be16(offset);
     gfs2_qstr2dirent(name, totlen - offset, ndent);
     return ndent;
 }
 
 
 /*
  * Takes a dent from which to grab space as an argument. Returns the
  * newly created dent.
  */
 static struct gfs2_dirent *gfs2_init_dirent(struct inode *inode,
                         struct gfs2_dirent *dent,
                         const struct qstr *name,
                         struct buffer_head *bh)
 {
     unsigned offset = 0;
 
     if (!gfs2_dirent_sentinel(dent))
         offset = GFS2_DIRENT_SIZE(be16_to_cpu(dent->de_name_len));
     return do_init_dirent(inode, dent, name, bh, offset);
 }
 
 static struct gfs2_dirent *gfs2_dirent_split_alloc(struct inode *inode,
                            struct buffer_head *bh,
                            const struct qstr *name,
                            void *ptr)
 {
     struct gfs2_dirent *dent;
     dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
                 gfs2_dirent_find_offset, name, ptr);
     if (IS_ERR_OR_NULL(dent))
         return dent;
     return do_init_dirent(inode, dent, name, bh,
                   (unsigned)(ptr - (void *)dent));
 }
 
 static int get_leaf(struct gfs2_inode *dip, u64 leaf_no,
             struct buffer_head **bhp)
 {
     int error;
 
     error = gfs2_meta_read(dip->i_gl, leaf_no, DIO_WAIT, 0, bhp);
     if (!error && gfs2_metatype_check(GFS2_SB(&dip->i_inode), *bhp, GFS2_METATYPE_LF)) {
         /* pr_info("block num=%llu\n", leaf_no); */
         error = -EIO;
     }
 
     return error;
 }
 
 /**
  * get_leaf_nr - Get a leaf number associated with the index
  * @dip: The GFS2 inode
  * @index: hash table index of the targeted leaf
  * @leaf_out: Resulting leaf block number
  *
  * Returns: 0 on success, error code otherwise
  */
 
 static int get_leaf_nr(struct gfs2_inode *dip, u32 index, u64 *leaf_out)
 {
     __be64 *hash;
     int error;
 
     hash = gfs2_dir_get_hash_table(dip);
     error = PTR_ERR_OR_ZERO(hash);
 
     if (!error)
         *leaf_out = be64_to_cpu(*(hash + index));
 
     return error;
 }
 
 static int get_first_leaf(struct gfs2_inode *dip, u32 index,
               struct buffer_head **bh_out)
 {
     u64 leaf_no;
     int error;
 
     error = get_leaf_nr(dip, index, &leaf_no);
     if (!error)
         error = get_leaf(dip, leaf_no, bh_out);
 
     return error;
 }
 
 static struct gfs2_dirent *gfs2_dirent_search(struct inode *inode,
                           const struct qstr *name,
                           gfs2_dscan_t scan,
                           struct buffer_head **pbh)
 {
     struct buffer_head *bh;
     struct gfs2_dirent *dent;
     struct gfs2_inode *ip = GFS2_I(inode);
     int error;
 
     if (ip->i_diskflags & GFS2_DIF_EXHASH) {
         struct gfs2_leaf *leaf;
         unsigned int hsize = BIT(ip->i_depth);
         unsigned int index;
         u64 ln;
         if (hsize * sizeof(u64) != i_size_read(inode)) {
             gfs2_consist_inode(ip);
             return ERR_PTR(-EIO);
         }
 
         index = name->hash >> (32 - ip->i_depth);
         error = get_first_leaf(ip, index, &bh);
         if (error)
             return ERR_PTR(error);
         do {
             dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
                         scan, name, NULL);
             if (dent)
                 goto got_dent;
             leaf = (struct gfs2_leaf *)bh->b_data;
             ln = be64_to_cpu(leaf->lf_next);
             brelse(bh);
             if (!ln)
                 break;
 
             error = get_leaf(ip, ln, &bh);
         } while(!error);
 
         return error ? ERR_PTR(error) : NULL;
     }
 
 
     error = gfs2_meta_inode_buffer(ip, &bh);
     if (error)
         return ERR_PTR(error);
     dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size, scan, name, NULL);
 got_dent:
     if (IS_ERR_OR_NULL(dent)) {
         brelse(bh);
         bh = NULL;
     }
     *pbh = bh;
     return dent;
 }
 
 static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh, u16 depth)
 {
     struct gfs2_inode *ip = GFS2_I(inode);
     unsigned int n = 1;
     u64 bn;
     int error;
     struct buffer_head *bh;
     struct gfs2_leaf *leaf;
     struct gfs2_dirent *dent;
     struct timespec64 tv = current_time(inode);
 
     error = gfs2_alloc_blocks(ip, &bn, &n, 0, NULL);
     if (error)
         return NULL;
     bh = gfs2_meta_new(ip->i_gl, bn);
     if (!bh)
         return NULL;
 
     gfs2_trans_remove_revoke(GFS2_SB(inode), bn, 1);
     gfs2_trans_add_meta(ip->i_gl, bh);
     gfs2_metatype_set(bh, GFS2_METATYPE_LF, GFS2_FORMAT_LF);
     leaf = (struct gfs2_leaf *)bh->b_data;
     leaf->lf_depth = cpu_to_be16(depth);
     leaf->lf_entries = 0;
     leaf->lf_dirent_format = cpu_to_be32(GFS2_FORMAT_DE);
     leaf->lf_next = 0;
     leaf->lf_inode = cpu_to_be64(ip->i_no_addr);
     leaf->lf_dist = cpu_to_be32(1);
     leaf->lf_nsec = cpu_to_be32(tv.tv_nsec);
     leaf->lf_sec = cpu_to_be64(tv.tv_sec);
     memset(leaf->lf_reserved2, 0, sizeof(leaf->lf_reserved2));
     dent = (struct gfs2_dirent *)(leaf+1);
     gfs2_qstr2dirent(&empty_name, bh->b_size - sizeof(struct gfs2_leaf), dent);
     *pbh = bh;
     return leaf;
 }
 
 /**
  * dir_make_exhash - Convert a stuffed directory into an ExHash directory
  * @inode: The directory inode to be converted to exhash
  *
  * Returns: 0 on success, error code otherwise
  */
 
 static int dir_make_exhash(struct inode *inode)
 {
     struct gfs2_inode *dip = GFS2_I(inode);
     struct gfs2_sbd *sdp = GFS2_SB(inode);
     struct gfs2_dirent *dent;
     struct qstr args;
     struct buffer_head *bh, *dibh;
     struct gfs2_leaf *leaf;
     int y;
     u32 x;
     __be64 *lp;
     u64 bn;
     int error;
 
     error = gfs2_meta_inode_buffer(dip, &dibh);
     if (error)
         return error;
 
     /*  Turn over a new leaf  */
 
     leaf = new_leaf(inode, &bh, 0);
     if (!leaf)
         return -ENOSPC;
     bn = bh->b_blocknr;
 
     gfs2_assert(sdp, dip->i_entries < BIT(16));
     leaf->lf_entries = cpu_to_be16(dip->i_entries);
 
     /*  Copy dirents  */
 
     gfs2_buffer_copy_tail(bh, sizeof(struct gfs2_leaf), dibh,
                  sizeof(struct gfs2_dinode));
 
     /*  Find last entry  */
 
     x = 0;
     args.len = bh->b_size - sizeof(struct gfs2_dinode) +
            sizeof(struct gfs2_leaf);
     args.name = bh->b_data;
     dent = gfs2_dirent_scan(&dip->i_inode, bh->b_data, bh->b_size,
                 gfs2_dirent_last, &args, NULL);
     if (!dent) {
         brelse(bh);
         brelse(dibh);
         return -EIO;
     }
     if (IS_ERR(dent)) {
         brelse(bh);
         brelse(dibh);
         return PTR_ERR(dent);
     }
 
     /*  Adjust the last dirent's record length
        (Remember that dent still points to the last entry.)  */
 
     dent->de_rec_len = cpu_to_be16(be16_to_cpu(dent->de_rec_len) +
         sizeof(struct gfs2_dinode) -
         sizeof(struct gfs2_leaf));
 
     brelse(bh);
 
     /*  We're done with the new leaf block, now setup the new
         hash table.  */
 
     gfs2_trans_add_meta(dip->i_gl, dibh);
     gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
 
     lp = (__be64 *)(dibh->b_data + sizeof(struct gfs2_dinode));
 
     for (x = sdp->sd_hash_ptrs; x--; lp++)
         *lp = cpu_to_be64(bn);
 
     i_size_write(inode, sdp->sd_sb.sb_bsize / 2);
     gfs2_add_inode_blocks(&dip->i_inode, 1);
     dip->i_diskflags |= GFS2_DIF_EXHASH;
 
     for (x = sdp->sd_hash_ptrs, y = -1; x; x >>= 1, y++) ;
     dip->i_depth = y;
 
     gfs2_dinode_out(dip, dibh->b_data);
 
     brelse(dibh);
 
     return 0;
 }
 
 /**
  * dir_split_leaf - Split a leaf block into two
  * @inode: The directory inode to be split
  * @name: name of the dirent we're trying to insert
  *
  * Returns: 0 on success, error code on failure
  */
 
 static int dir_split_leaf(struct inode *inode, const struct qstr *name)
 {
     struct gfs2_inode *dip = GFS2_I(inode);
     struct buffer_head *nbh, *obh, *dibh;
     struct gfs2_leaf *nleaf, *oleaf;
     struct gfs2_dirent *dent = NULL, *prev = NULL, *next = NULL, *new;
     u32 start, len, half_len, divider;
     u64 bn, leaf_no;
     __be64 *lp;
     u32 index;
     int x;
     int error;
 
     index = name->hash >> (32 - dip->i_depth);
     error = get_leaf_nr(dip, index, &leaf_no);
     if (error)
         return error;
 
     /*  Get the old leaf block  */
     error = get_leaf(dip, leaf_no, &obh);
     if (error)
         return error;
 
     oleaf = (struct gfs2_leaf *)obh->b_data;
     if (dip->i_depth == be16_to_cpu(oleaf->lf_depth)) {
         brelse(obh);
         return 1; /* can't split */
     }
 
     gfs2_trans_add_meta(dip->i_gl, obh);
 
     nleaf = new_leaf(inode, &nbh, be16_to_cpu(oleaf->lf_depth) + 1);
     if (!nleaf) {
         brelse(obh);
         return -ENOSPC;
     }
     bn = nbh->b_blocknr;
 
     /*  Compute the start and len of leaf pointers in the hash table.  */
     len = BIT(dip->i_depth - be16_to_cpu(oleaf->lf_depth));
     half_len = len >> 1;
     if (!half_len) {
         fs_warn(GFS2_SB(inode), "i_depth %u lf_depth %u index %u\n",
             dip->i_depth, be16_to_cpu(oleaf->lf_depth), index);
         gfs2_consist_inode(dip);
         error = -EIO;
         goto fail_brelse;
     }
 
     start = (index & ~(len - 1));
 
     /* Change the pointers.
        Don't bother distinguishing stuffed from non-stuffed.
        This code is complicated enough already. */
     lp = kmalloc_array(half_len, sizeof(__be64), GFP_NOFS);
     if (!lp) {
         error = -ENOMEM;
         goto fail_brelse;
     }
 
     /*  Change the pointers  */
     for (x = 0; x < half_len; x++)
         lp[x] = cpu_to_be64(bn);
 
     gfs2_dir_hash_inval(dip);
 
     error = gfs2_dir_write_data(dip, (char *)lp, start * sizeof(u64),
                     half_len * sizeof(u64));
     if (error != half_len * sizeof(u64)) {
         if (error >= 0)
             error = -EIO;
         goto fail_lpfree;
     }
 
     kfree(lp);
 
     /*  Compute the divider  */
     divider = (start + half_len) << (32 - dip->i_depth);
 
     /*  Copy the entries  */
     dent = (struct gfs2_dirent *)(obh->b_data + sizeof(struct gfs2_leaf));
 
     do {
         next = dent;
         if (dirent_next(dip, obh, &next))
             next = NULL;
 
         if (!gfs2_dirent_sentinel(dent) &&
             be32_to_cpu(dent->de_hash) < divider) {
             struct qstr str;
             void *ptr = ((char *)dent - obh->b_data) + nbh->b_data;
             str.name = (char*)(dent+1);
             str.len = be16_to_cpu(dent->de_name_len);
             str.hash = be32_to_cpu(dent->de_hash);
             new = gfs2_dirent_split_alloc(inode, nbh, &str, ptr);
             if (IS_ERR(new)) {
                 error = PTR_ERR(new);
                 break;
             }
 
             new->de_inum = dent->de_inum; /* No endian worries */
             new->de_type = dent->de_type; /* No endian worries */
             be16_add_cpu(&nleaf->lf_entries, 1);
 
             dirent_del(dip, obh, prev, dent);
 
             if (!oleaf->lf_entries)
                 gfs2_consist_inode(dip);
             be16_add_cpu(&oleaf->lf_entries, -1);
 
             if (!prev)
                 prev = dent;
         } else {
             prev = dent;
         }
         dent = next;
     } while (dent);
 
     oleaf->lf_depth = nleaf->lf_depth;
 
     error = gfs2_meta_inode_buffer(dip, &dibh);
     if (!gfs2_assert_withdraw(GFS2_SB(&dip->i_inode), !error)) {
         gfs2_trans_add_meta(dip->i_gl, dibh);
         gfs2_add_inode_blocks(&dip->i_inode, 1);
         gfs2_dinode_out(dip, dibh->b_data);
         brelse(dibh);
     }
 
     brelse(obh);
     brelse(nbh);
 
     return error;
 
 fail_lpfree:
     kfree(lp);
 
 fail_brelse:
     brelse(obh);
     brelse(nbh);
     return error;
 }
 
 /**
  * dir_double_exhash - Double size of ExHash table
  * @dip: The GFS2 dinode
  *
  * Returns: 0 on success, error code on failure
  */
 
 static int dir_double_exhash(struct gfs2_inode *dip)
 {
     struct buffer_head *dibh;
     u32 hsize;
     u32 hsize_bytes;
     __be64 *hc;
     __be64 *hc2, *h;
     int x;
     int error = 0;
 
     hsize = BIT(dip->i_depth);
     hsize_bytes = hsize * sizeof(__be64);
 
     hc = gfs2_dir_get_hash_table(dip);
     if (IS_ERR(hc))
         return PTR_ERR(hc);
 
     hc2 = kmalloc_array(hsize_bytes, 2, GFP_NOFS | __GFP_NOWARN);
     if (hc2 == NULL)
         hc2 = __vmalloc(hsize_bytes * 2, GFP_NOFS);
 
     if (!hc2)
         return -ENOMEM;
 
     h = hc2;
     error = gfs2_meta_inode_buffer(dip, &dibh);
     if (error)
         goto out_kfree;
 
     for (x = 0; x < hsize; x++) {
         *h++ = *hc;
         *h++ = *hc;
         hc++;
     }
 
     error = gfs2_dir_write_data(dip, (char *)hc2, 0, hsize_bytes * 2);
     if (error != (hsize_bytes * 2))
         goto fail;
 
     gfs2_dir_hash_inval(dip);
     dip->i_hash_cache = hc2;
     dip->i_depth++;
     gfs2_dinode_out(dip, dibh->b_data);
     brelse(dibh);
     return 0;
 
 fail:
     /* Replace original hash table & size */
     gfs2_dir_write_data(dip, (char *)hc, 0, hsize_bytes);
     i_size_write(&dip->i_inode, hsize_bytes);
     gfs2_dinode_out(dip, dibh->b_data);
     brelse(dibh);
 out_kfree:
     kvfree(hc2);
     return error;
 }
 
 /**
  * compare_dents - compare directory entries by hash value
  * @a: first dent
  * @b: second dent
  *
  * When comparing the hash entries of @a to @b:
  *   gt: returns 1
  *   lt: returns -1
  *   eq: returns 0
  */
 
 static int compare_dents(const void *a, const void *b)
 {
     const struct gfs2_dirent *dent_a, *dent_b;
     u32 hash_a, hash_b;
     int ret = 0;
 
     dent_a = *(const struct gfs2_dirent **)a;
     hash_a = dent_a->de_cookie;
 
     dent_b = *(const struct gfs2_dirent **)b;
     hash_b = dent_b->de_cookie;
 
     if (hash_a > hash_b)
         ret = 1;
     else if (hash_a < hash_b)
         ret = -1;
     else {
         unsigned int len_a = be16_to_cpu(dent_a->de_name_len);
         unsigned int len_b = be16_to_cpu(dent_b->de_name_len);
 
         if (len_a > len_b)
             ret = 1;
         else if (len_a < len_b)
             ret = -1;
         else
             ret = memcmp(dent_a + 1, dent_b + 1, len_a);
     }
 
     return ret;
 }
 
 /**
  * do_filldir_main - read out directory entries
  * @dip: The GFS2 inode
  * @ctx: what to feed the entries to
  * @darr: an array of struct gfs2_dirent pointers to read
  * @entries: the number of entries in darr
  * @sort_start: index of the directory array to start our sort
  * @copied: pointer to int that's non-zero if a entry has been copied out
  *
  * Jump through some hoops to make sure that if there are hash collsions,
  * they are read out at the beginning of a buffer.  We want to minimize
  * the possibility that they will fall into different readdir buffers or
  * that someone will want to seek to that location.
  *
  * Returns: errno, >0 if the actor tells you to stop
  */
 
 static int do_filldir_main(struct gfs2_inode *dip, struct dir_context *ctx,
                struct gfs2_dirent **darr, u32 entries,
                u32 sort_start, int *copied)
 {
     const struct gfs2_dirent *dent, *dent_next;
     u64 off, off_next;
     unsigned int x, y;
     int run = 0;
 
     if (sort_start < entries)
         sort(&darr[sort_start], entries - sort_start,
              sizeof(struct gfs2_dirent *), compare_dents, NULL);
 
     dent_next = darr[0];
     off_next = dent_next->de_cookie;
 
     for (x = 0, y = 1; x < entries; x++, y++) {
         dent = dent_next;
         off = off_next;
 
         if (y < entries) {
             dent_next = darr[y];
             off_next = dent_next->de_cookie;
 
             if (off < ctx->pos)
                 continue;
             ctx->pos = off;
 
             if (off_next == off) {
                 if (*copied && !run)
                     return 1;
                 run = 1;
             } else
                 run = 0;
         } else {
             if (off < ctx->pos)
                 continue;
             ctx->pos = off;
         }
 
         if (!dir_emit(ctx, (const char *)(dent + 1),
                 be16_to_cpu(dent->de_name_len),
                 be64_to_cpu(dent->de_inum.no_addr),
                 be16_to_cpu(dent->de_type)))
             return 1;
 
         *copied = 1;
     }
 
     /* Increment the ctx->pos by one, so the next time we come into the
        do_filldir fxn, we get the next entry instead of the last one in the
        current leaf */
 
     ctx->pos++;
 
     return 0;
 }
 
 static void *gfs2_alloc_sort_buffer(unsigned size)
 {
     void *ptr = NULL;
 
     if (size < KMALLOC_MAX_SIZE)
         ptr = kmalloc(size, GFP_NOFS | __GFP_NOWARN);
     if (!ptr)
         ptr = __vmalloc(size, GFP_NOFS);
     return ptr;
 }
 
 
 static int gfs2_set_cookies(struct gfs2_sbd *sdp, struct buffer_head *bh,
                 unsigned leaf_nr, struct gfs2_dirent **darr,
                 unsigned entries)
 {
     int sort_id = -1;
     int i;
     
     for (i = 0; i < entries; i++) {
         unsigned offset;
 
         darr[i]->de_cookie = be32_to_cpu(darr[i]->de_hash);
         darr[i]->de_cookie = gfs2_disk_hash2offset(darr[i]->de_cookie);
 
         if (!sdp->sd_args.ar_loccookie)
             continue;
         offset = (char *)(darr[i]) -
             (bh->b_data + gfs2_dirent_offset(sdp, bh->b_data));
         offset /= GFS2_MIN_DIRENT_SIZE;
         offset += leaf_nr * sdp->sd_max_dents_per_leaf;
         if (offset >= GFS2_USE_HASH_FLAG ||
             leaf_nr >= GFS2_USE_HASH_FLAG) {
             darr[i]->de_cookie |= GFS2_USE_HASH_FLAG;
             if (sort_id < 0)
                 sort_id = i;
             continue;
         }
         darr[i]->de_cookie &= GFS2_HASH_INDEX_MASK;
         darr[i]->de_cookie |= offset;
     }
     return sort_id;
 }   
 
 
 static int gfs2_dir_read_leaf(struct inode *inode, struct dir_context *ctx,
                   int *copied, unsigned *depth,
                   u64 leaf_no)
 {
     struct gfs2_inode *ip = GFS2_I(inode);
     struct gfs2_sbd *sdp = GFS2_SB(inode);
     struct buffer_head *bh;
     struct gfs2_leaf *lf;
     unsigned entries = 0, entries2 = 0;
     unsigned leaves = 0, leaf = 0, offset, sort_offset;
     struct gfs2_dirent **darr, *dent;
     struct dirent_gather g;
     struct buffer_head **larr;
     int error, i, need_sort = 0, sort_id;
     u64 lfn = leaf_no;
 
     do {
         error = get_leaf(ip, lfn, &bh);
         if (error)
             goto out;
         lf = (struct gfs2_leaf *)bh->b_data;
         if (leaves == 0)
             *depth = be16_to_cpu(lf->lf_depth);
         entries += be16_to_cpu(lf->lf_entries);
         leaves++;
         lfn = be64_to_cpu(lf->lf_next);
         brelse(bh);
     } while(lfn);
 
     if (*depth < GFS2_DIR_MAX_DEPTH || !sdp->sd_args.ar_loccookie) {
         need_sort = 1;
         sort_offset = 0;
     }
 
     if (!entries)
         return 0;
 
     error = -ENOMEM;
     /*
      * The extra 99 entries are not normally used, but are a buffer
      * zone in case the number of entries in the leaf is corrupt.
      * 99 is the maximum number of entries that can fit in a single
      * leaf block.
      */
     larr = gfs2_alloc_sort_buffer((leaves + entries + 99) * sizeof(void *));
     if (!larr)
         goto out;
     darr = (struct gfs2_dirent **)(larr + leaves);
     g.pdent = (const struct gfs2_dirent **)darr;
     g.offset = 0;
     lfn = leaf_no;
 
     do {
         error = get_leaf(ip, lfn, &bh);
         if (error)
             goto out_free;
         lf = (struct gfs2_leaf *)bh->b_data;
         lfn = be64_to_cpu(lf->lf_next);
         if (lf->lf_entries) {
             offset = g.offset;
             entries2 += be16_to_cpu(lf->lf_entries);
             dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
                         gfs2_dirent_gather, NULL, &g);
             error = PTR_ERR(dent);
             if (IS_ERR(dent))
                 goto out_free;
             if (entries2 != g.offset) {
                 fs_warn(sdp, "Number of entries corrupt in dir "
                         "leaf %llu, entries2 (%u) != "
                         "g.offset (%u)\n",
                     (unsigned long long)bh->b_blocknr,
                     entries2, g.offset);
                 gfs2_consist_inode(ip);
                 error = -EIO;
                 goto out_free;
             }
             error = 0;
             sort_id = gfs2_set_cookies(sdp, bh, leaf, &darr[offset],
                            be16_to_cpu(lf->lf_entries));
             if (!need_sort && sort_id >= 0) {
                 need_sort = 1;
                 sort_offset = offset + sort_id;
             }
             larr[leaf++] = bh;
         } else {
             larr[leaf++] = NULL;
             brelse(bh);
         }
     } while(lfn);
 
     BUG_ON(entries2 != entries);
     error = do_filldir_main(ip, ctx, darr, entries, need_sort ?
                 sort_offset : entries, copied);
 out_free:
     for(i = 0; i < leaf; i++)
         brelse(larr[i]);
     kvfree(larr);
 out:
     return error;
 }
 
 /**
  * gfs2_dir_readahead - Issue read-ahead requests for leaf blocks.
  * @inode: the directory inode
  * @hsize: hash table size
  * @index: index into the hash table
  * @f_ra: read-ahead parameters
  *
  * Note: we can't calculate each index like dir_e_read can because we don't
  * have the leaf, and therefore we don't have the depth, and therefore we
  * don't have the length. So we have to just read enough ahead to make up
  * for the loss of information.
  */
 static void gfs2_dir_readahead(struct inode *inode, unsigned hsize, u32 index,
                    struct file_ra_state *f_ra)
 {
     struct gfs2_inode *ip = GFS2_I(inode);
     struct gfs2_glock *gl = ip->i_gl;
     struct buffer_head *bh;
     u64 blocknr = 0, last;
     unsigned count;
 
     /* First check if we've already read-ahead for the whole range. */
     if (index + MAX_RA_BLOCKS < f_ra->start)
         return;
 
     f_ra->start = max((pgoff_t)index, f_ra->start);
     for (count = 0; count < MAX_RA_BLOCKS; count++) {
         if (f_ra->start >= hsize) /* if exceeded the hash table */
             break;
 
         last = blocknr;
         blocknr = be64_to_cpu(ip->i_hash_cache[f_ra->start]);
         f_ra->start++;
         if (blocknr == last)
             continue;
 
         bh = gfs2_getbuf(gl, blocknr, 1);
         if (trylock_buffer(bh)) {
             if (buffer_uptodate(bh)) {
                 unlock_buffer(bh);
                 brelse(bh);
                 continue;
             }
             bh->b_end_io = end_buffer_read_sync;
             submit_bh(REQ_OP_READ | REQ_RAHEAD | REQ_META |
                   REQ_PRIO, bh);
             continue;
         }
         brelse(bh);
     }
 }
 
 /**
  * dir_e_read - Reads the entries from a directory into a filldir buffer
  * @inode: the directory inode
  * @ctx: actor to feed the entries to
  * @f_ra: read-ahead parameters
  *
  * Returns: errno
  */
 
 static int dir_e_read(struct inode *inode, struct dir_context *ctx,
               struct file_ra_state *f_ra)
 {
     struct gfs2_inode *dip = GFS2_I(inode);
     u32 hsize, len = 0;
     u32 hash, index;
     __be64 *lp;
     int copied = 0;
     int error = 0;
     unsigned depth = 0;
 
     hsize = BIT(dip->i_depth);
     hash = gfs2_dir_offset2hash(ctx->pos);
     index = hash >> (32 - dip->i_depth);
 
     if (dip->i_hash_cache == NULL)
         f_ra->start = 0;
     lp = gfs2_dir_get_hash_table(dip);
     if (IS_ERR(lp))
         return PTR_ERR(lp);
 
     gfs2_dir_readahead(inode, hsize, index, f_ra);
 
     while (index < hsize) {
         error = gfs2_dir_read_leaf(inode, ctx,
                        &copied, &depth,
                        be64_to_cpu(lp[index]));
         if (error)
             break;
 
         len = BIT(dip->i_depth - depth);
         index = (index & ~(len - 1)) + len;
     }
 
     if (error > 0)
         error = 0;
     return error;
 }
 
 int gfs2_dir_read(struct inode *inode, struct dir_context *ctx,
           struct file_ra_state *f_ra)
 {
     struct gfs2_inode *dip = GFS2_I(inode);
     struct gfs2_sbd *sdp = GFS2_SB(inode);
     struct dirent_gather g;
     struct gfs2_dirent **darr, *dent;
     struct buffer_head *dibh;
     int copied = 0;
     int error;
 
     if (!dip->i_entries)
         return 0;
 
     if (dip->i_diskflags & GFS2_DIF_EXHASH)
         return dir_e_read(inode, ctx, f_ra);
 
     if (!gfs2_is_stuffed(dip)) {
         gfs2_consist_inode(dip);
         return -EIO;
     }
 
     error = gfs2_meta_inode_buffer(dip, &dibh);
     if (error)
         return error;
 
     error = -ENOMEM;
     /* 96 is max number of dirents which can be stuffed into an inode */
     darr = kmalloc_array(96, sizeof(struct gfs2_dirent *), GFP_NOFS);
     if (darr) {
         g.pdent = (const struct gfs2_dirent **)darr;
         g.offset = 0;
         dent = gfs2_dirent_scan(inode, dibh->b_data, dibh->b_size,
                     gfs2_dirent_gather, NULL, &g);
         if (IS_ERR(dent)) {
             error = PTR_ERR(dent);
             goto out;
         }
         if (dip->i_entries != g.offset) {
             fs_warn(sdp, "Number of entries corrupt in dir %llu, "
                 "ip->i_entries (%u) != g.offset (%u)\n",
                 (unsigned long long)dip->i_no_addr,
                 dip->i_entries,
                 g.offset);
             gfs2_consist_inode(dip);
             error = -EIO;
             goto out;
         }
         gfs2_set_cookies(sdp, dibh, 0, darr, dip->i_entries);
         error = do_filldir_main(dip, ctx, darr,
                     dip->i_entries, 0, &copied);
 out:
         kfree(darr);
     }
 
     if (error > 0)
         error = 0;
 
     brelse(dibh);
 
     return error;
 }
 
 /**
  * gfs2_dir_search - Search a directory
  * @dir: The GFS2 directory inode
  * @name: The name we are looking up
  * @fail_on_exist: Fail if the name exists rather than looking it up
  *
  * This routine searches a directory for a file or another directory.
  * Assumes a glock is held on dip.
  *
  * Returns: errno
  */
 
 struct inode *gfs2_dir_search(struct inode *dir, const struct qstr *name,
                   bool fail_on_exist)
 {
     struct buffer_head *bh;
     struct gfs2_dirent *dent;
     u64 addr, formal_ino;
     u16 dtype;
 
     dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
     if (dent) {
         struct inode *inode;
         u16 rahead;
 
         if (IS_ERR(dent))
             return ERR_CAST(dent);
         dtype = be16_to_cpu(dent->de_type);
         rahead = be16_to_cpu(dent->de_rahead);
         addr = be64_to_cpu(dent->de_inum.no_addr);
         formal_ino = be64_to_cpu(dent->de_inum.no_formal_ino);
         brelse(bh);
         if (fail_on_exist)
             return ERR_PTR(-EEXIST);
         inode = gfs2_inode_lookup(dir->i_sb, dtype, addr, formal_ino,
                       GFS2_BLKST_FREE /* ignore */);
         if (!IS_ERR(inode))
             GFS2_I(inode)->i_rahead = rahead;
         return inode;
     }
     return ERR_PTR(-ENOENT);
 }
 
 int gfs2_dir_check(struct inode *dir, const struct qstr *name,
            const struct gfs2_inode *ip)
 {
     struct buffer_head *bh;
     struct gfs2_dirent *dent;
     int ret = -ENOENT;
 
     dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
     if (dent) {
         if (IS_ERR(dent))
             return PTR_ERR(dent);
         if (ip) {
             if (be64_to_cpu(dent->de_inum.no_addr) != ip->i_no_addr)
                 goto out;
             if (be64_to_cpu(dent->de_inum.no_formal_ino) !=
                 ip->i_no_formal_ino)
                 goto out;
             if (unlikely(IF2DT(ip->i_inode.i_mode) !=
                 be16_to_cpu(dent->de_type))) {
                 gfs2_consist_inode(GFS2_I(dir));
                 ret = -EIO;
                 goto out;
             }
         }
         ret = 0;
 out:
         brelse(bh);
     }
     return ret;
 }
 
 /**
  * dir_new_leaf - Add a new leaf onto hash chain
  * @inode: The directory
  * @name: The name we are adding
  *
  * This adds a new dir leaf onto an existing leaf when there is not
  * enough space to add a new dir entry. This is a last resort after
  * we've expanded the hash table to max size and also split existing
  * leaf blocks, so it will only occur for very large directories.
  *
  * The dist parameter is set to 1 for leaf blocks directly attached
  * to the hash table, 2 for one layer of indirection, 3 for two layers
  * etc. We are thus able to tell the difference between an old leaf
  * with dist set to zero (i.e. "don't know") and a new one where we
  * set this information for debug/fsck purposes.
  *
  * Returns: 0 on success, or -ve on error
  */
 
 static int dir_new_leaf(struct inode *inode, const struct qstr *name)
 {
     struct buffer_head *bh, *obh;
     struct gfs2_inode *ip = GFS2_I(inode);
     struct gfs2_leaf *leaf, *oleaf;
     u32 dist = 1;
     int error;
     u32 index;
     u64 bn;
 
     index = name->hash >> (32 - ip->i_depth);
     error = get_first_leaf(ip, index, &obh);
     if (error)
         return error;
     do {
         dist++;
         oleaf = (struct gfs2_leaf *)obh->b_data;
         bn = be64_to_cpu(oleaf->lf_next);
         if (!bn)
             break;
         brelse(obh);
         error = get_leaf(ip, bn, &obh);
         if (error)
             return error;
     } while(1);
 
     gfs2_trans_add_meta(ip->i_gl, obh);
 
     leaf = new_leaf(inode, &bh, be16_to_cpu(oleaf->lf_depth));
     if (!leaf) {
         brelse(obh);
         return -ENOSPC;
     }
     leaf->lf_dist = cpu_to_be32(dist);
     oleaf->lf_next = cpu_to_be64(bh->b_blocknr);
     brelse(bh);
     brelse(obh);
 
     error = gfs2_meta_inode_buffer(ip, &bh);
     if (error)
         return error;
     gfs2_trans_add_meta(ip->i_gl, bh);
     gfs2_add_inode_blocks(&ip->i_inode, 1);
     gfs2_dinode_out(ip, bh->b_data);
     brelse(bh);
     return 0;
 }
 
 static u16 gfs2_inode_ra_len(const struct gfs2_inode *ip)
 {
     u64 where = ip->i_no_addr + 1;
     if (ip->i_eattr == where)
         return 1;
     return 0;
 }
 
 /**
  * gfs2_dir_add - Add new filename into directory
  * @inode: The directory inode
  * @name: The new name
  * @nip: The GFS2 inode to be linked in to the directory
  * @da: The directory addition info
  *
  * If the call to gfs2_diradd_alloc_required resulted in there being
  * no need to allocate any new directory blocks, then it will contain
  * a pointer to the directory entry and the bh in which it resides. We
  * can use that without having to repeat the search. If there was no
  * free space, then we must now create more space.
  *
  * Returns: 0 on success, error code on failure
  */
 
 int gfs2_dir_add(struct inode *inode, const struct qstr *name,
          const struct gfs2_inode *nip, struct gfs2_diradd *da)
 {
     struct gfs2_inode *ip = GFS2_I(inode);
     struct buffer_head *bh = da->bh;
     struct gfs2_dirent *dent = da->dent;
     struct timespec64 tv;
     struct gfs2_leaf *leaf;
     int error;
 
     while(1) {
         if (da->bh == NULL) {
             dent = gfs2_dirent_search(inode, name,
                           gfs2_dirent_find_space, &bh);
         }
         if (dent) {
             if (IS_ERR(dent))
                 return PTR_ERR(dent);
             dent = gfs2_init_dirent(inode, dent, name, bh);
             gfs2_inum_out(nip, dent);
             dent->de_type = cpu_to_be16(IF2DT(nip->i_inode.i_mode));
             dent->de_rahead = cpu_to_be16(gfs2_inode_ra_len(nip));
             tv = current_time(&ip->i_inode);
             if (ip->i_diskflags & GFS2_DIF_EXHASH) {
                 leaf = (struct gfs2_leaf *)bh->b_data;
                 be16_add_cpu(&leaf->lf_entries, 1);
                 leaf->lf_nsec = cpu_to_be32(tv.tv_nsec);
                 leaf->lf_sec = cpu_to_be64(tv.tv_sec);
             }
             da->dent = NULL;
             da->bh = NULL;
             brelse(bh);
             ip->i_entries++;
             ip->i_inode.i_mtime = ip->i_inode.i_ctime = tv;
             if (S_ISDIR(nip->i_inode.i_mode))
                 inc_nlink(&ip->i_inode);
             mark_inode_dirty(inode);
             error = 0;
             break;
         }
         if (!(ip->i_diskflags & GFS2_DIF_EXHASH)) {
             error = dir_make_exhash(inode);
             if (error)
                 break;
             continue;
         }
         error = dir_split_leaf(inode, name);
         if (error == 0)
             continue;
         if (error < 0)
             break;
         if (ip->i_depth < GFS2_DIR_MAX_DEPTH) {
             error = dir_double_exhash(ip);
             if (error)
                 break;
             error = dir_split_leaf(inode, name);
             if (error < 0)
                 break;
             if (error == 0)
                 continue;
         }
         error = dir_new_leaf(inode, name);
         if (!error)
             continue;
         error = -ENOSPC;
         break;
     }
     return error;
 }
 
 
 /**
  * gfs2_dir_del - Delete a directory entry
  * @dip: The GFS2 inode
  * @dentry: The directory entry we want to delete
  *
  * Returns: 0 on success, error code on failure
  */
 
 int gfs2_dir_del(struct gfs2_inode *dip, const struct dentry *dentry)
 {
     const struct qstr *name = &dentry->d_name;
     struct gfs2_dirent *dent, *prev = NULL;
     struct buffer_head *bh;
     struct timespec64 tv = current_time(&dip->i_inode);
 
     /* Returns _either_ the entry (if its first in block) or the
        previous entry otherwise */
     dent = gfs2_dirent_search(&dip->i_inode, name, gfs2_dirent_prev, &bh);
     if (!dent) {
         gfs2_consist_inode(dip);
         return -EIO;
     }
     if (IS_ERR(dent)) {
         gfs2_consist_inode(dip);
         return PTR_ERR(dent);
     }
     /* If not first in block, adjust pointers accordingly */
     if (gfs2_dirent_find(dent, name, NULL) == 0) {
         prev = dent;
         dent = (struct gfs2_dirent *)((char *)dent + be16_to_cpu(prev->de_rec_len));
     }
 
     dirent_del(dip, bh, prev, dent);
     if (dip->i_diskflags & GFS2_DIF_EXHASH) {
         struct gfs2_leaf *leaf = (struct gfs2_leaf *)bh->b_data;
         u16 entries = be16_to_cpu(leaf->lf_entries);
         if (!entries)
             gfs2_consist_inode(dip);
         leaf->lf_entries = cpu_to_be16(--entries);
         leaf->lf_nsec = cpu_to_be32(tv.tv_nsec);
         leaf->lf_sec = cpu_to_be64(tv.tv_sec);
     }
     brelse(bh);
 
     if (!dip->i_entries)
         gfs2_consist_inode(dip);
     dip->i_entries--;
     dip->i_inode.i_mtime = dip->i_inode.i_ctime = tv;
     if (d_is_dir(dentry))
         drop_nlink(&dip->i_inode);
     mark_inode_dirty(&dip->i_inode);
 
     return 0;
 }
 
 /**
  * gfs2_dir_mvino - Change inode number of directory entry
  * @dip: The GFS2 directory inode
  * @filename: the filename to be moved
  * @nip: the new GFS2 inode
  * @new_type: the de_type of the new dirent
  *
  * This routine changes the inode number of a directory entry.  It's used
  * by rename to change ".." when a directory is moved.
  * Assumes a glock is held on dvp.
  *
  * Returns: errno
  */
 
 int gfs2_dir_mvino(struct gfs2_inode *dip, const struct qstr *filename,
            const struct gfs2_inode *nip, unsigned int new_type)
 {
     struct buffer_head *bh;
     struct gfs2_dirent *dent;
 
     dent = gfs2_dirent_search(&dip->i_inode, filename, gfs2_dirent_find, &bh);
     if (!dent) {
         gfs2_consist_inode(dip);
         return -EIO;
     }
     if (IS_ERR(dent))
         return PTR_ERR(dent);
 
     gfs2_trans_add_meta(dip->i_gl, bh);
     gfs2_inum_out(nip, dent);
     dent->de_type = cpu_to_be16(new_type);
     brelse(bh);
 
     dip->i_inode.i_mtime = dip->i_inode.i_ctime = current_time(&dip->i_inode);
     mark_inode_dirty_sync(&dip->i_inode);
     return 0;
 }
 
 /**
  * leaf_dealloc - Deallocate a directory leaf
  * @dip: the directory
  * @index: the hash table offset in the directory
  * @len: the number of pointers to this leaf
  * @leaf_no: the leaf number
  * @leaf_bh: buffer_head for the starting leaf
  * @last_dealloc: 1 if this is the final dealloc for the leaf, else 0
  *
  * Returns: errno
  */
 
 static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len,
             u64 leaf_no, struct buffer_head *leaf_bh,
             int last_dealloc)
 {
     struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
     struct gfs2_leaf *tmp_leaf;
     struct gfs2_rgrp_list rlist;
     struct buffer_head *bh, *dibh;
     u64 blk, nblk;
     unsigned int rg_blocks = 0, l_blocks = 0;
     char *ht;
     unsigned int x, size = len * sizeof(u64);
     int error;
 
     error = gfs2_rindex_update(sdp);
     if (error)
         return error;
 
     memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));
 
     ht = kzalloc(size, GFP_NOFS | __GFP_NOWARN);
     if (ht == NULL)
         ht = __vmalloc(size, GFP_NOFS | __GFP_NOWARN | __GFP_ZERO);
     if (!ht)
         return -ENOMEM;
 
     error = gfs2_quota_hold(dip, NO_UID_QUOTA_CHANGE, NO_GID_QUOTA_CHANGE);
     if (error)
         goto out;
 
     /*  Count the number of leaves  */
     bh = leaf_bh;
 
     for (blk = leaf_no; blk; blk = nblk) {
         if (blk != leaf_no) {
             error = get_leaf(dip, blk, &bh);
             if (error)
                 goto out_rlist;
         }
         tmp_leaf = (struct gfs2_leaf *)bh->b_data;
         nblk = be64_to_cpu(tmp_leaf->lf_next);
         if (blk != leaf_no)
             brelse(bh);
 
         gfs2_rlist_add(dip, &rlist, blk);
         l_blocks++;
     }
 
     gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE, LM_FLAG_NODE_SCOPE);
 
     for (x = 0; x < rlist.rl_rgrps; x++) {
         struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(rlist.rl_ghs[x].gh_gl);
 
         rg_blocks += rgd->rd_length;
     }
 
     error = gfs2_glock_nq_m(rlist.rl_rgrps, rlist.rl_ghs);
     if (error)
         goto out_rlist;
 
     error = gfs2_trans_begin(sdp,
             rg_blocks + (DIV_ROUND_UP(size, sdp->sd_jbsize) + 1) +
             RES_DINODE + RES_STATFS + RES_QUOTA, RES_DINODE +
                  l_blocks);
     if (error)
         goto out_rg_gunlock;
 
     bh = leaf_bh;
 
     for (blk = leaf_no; blk; blk = nblk) {
         struct gfs2_rgrpd *rgd;
 
         if (blk != leaf_no) {
             error = get_leaf(dip, blk, &bh);
             if (error)
                 goto out_end_trans;
         }
         tmp_leaf = (struct gfs2_leaf *)bh->b_data;
         nblk = be64_to_cpu(tmp_leaf->lf_next);
         if (blk != leaf_no)
             brelse(bh);
 
         rgd = gfs2_blk2rgrpd(sdp, blk, true);
         gfs2_free_meta(dip, rgd, blk, 1);
         gfs2_add_inode_blocks(&dip->i_inode, -1);
     }
 
     error = gfs2_dir_write_data(dip, ht, index * sizeof(u64), size);
     if (error != size) {
         if (error >= 0)
             error = -EIO;
         goto out_end_trans;
     }
 
     error = gfs2_meta_inode_buffer(dip, &dibh);
     if (error)
         goto out_end_trans;
 
     gfs2_trans_add_meta(dip->i_gl, dibh);
     /* On the last dealloc, make this a regular file in case we crash.
        (We don't want to free these blocks a second time.)  */
     if (last_dealloc)
         dip->i_inode.i_mode = S_IFREG;
     gfs2_dinode_out(dip, dibh->b_data);
     brelse(dibh);
 
 out_end_trans:
     gfs2_trans_end(sdp);
 out_rg_gunlock:
     gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs);
 out_rlist:
     gfs2_rlist_free(&rlist);
     gfs2_quota_unhold(dip);
 out:
     kvfree(ht);
     return error;
 }
 
 /**
  * gfs2_dir_exhash_dealloc - free all the leaf blocks in a directory
  * @dip: the directory
  *
  * Dealloc all on-disk directory leaves to FREEMETA state
  * Change on-disk inode type to "regular file"
  *
  * Returns: errno
  */
 
 int gfs2_dir_exhash_dealloc(struct gfs2_inode *dip)
 {
     struct buffer_head *bh;
     struct gfs2_leaf *leaf;
     u32 hsize, len;
     u32 index = 0, next_index;
     __be64 *lp;
     u64 leaf_no;
     int error = 0, last;
 
     hsize = BIT(dip->i_depth);
 
     lp = gfs2_dir_get_hash_table(dip);
     if (IS_ERR(lp))
         return PTR_ERR(lp);
 
     while (index < hsize) {
         leaf_no = be64_to_cpu(lp[index]);
         if (leaf_no) {
             error = get_leaf(dip, leaf_no, &bh);
             if (error)
                 goto out;
             leaf = (struct gfs2_leaf *)bh->b_data;
             len = BIT(dip->i_depth - be16_to_cpu(leaf->lf_depth));
 
             next_index = (index & ~(len - 1)) + len;
             last = ((next_index >= hsize) ? 1 : 0);
             error = leaf_dealloc(dip, index, len, leaf_no, bh,
                          last);
             brelse(bh);
             if (error)
                 goto out;
             index = next_index;
         } else
             index++;
     }
 
     if (index != hsize) {
         gfs2_consist_inode(dip);
         error = -EIO;
     }
 
 out:
 
     return error;
 }
 
 /**
  * gfs2_diradd_alloc_required - find if adding entry will require an allocation
  * @inode: the directory inode being written to
  * @name: the filename that's going to be added
  * @da: The structure to return dir alloc info
  *
  * Returns: 0 if ok, -ve on error
  */
 
 int gfs2_diradd_alloc_required(struct inode *inode, const struct qstr *name,
                    struct gfs2_diradd *da)
 {
     struct gfs2_inode *ip = GFS2_I(inode);
     struct gfs2_sbd *sdp = GFS2_SB(inode);
     const unsigned int extra = sizeof(struct gfs2_dinode) - sizeof(struct gfs2_leaf);
     struct gfs2_dirent *dent;
     struct buffer_head *bh;
 
     da->nr_blocks = 0;
     da->bh = NULL;
     da->dent = NULL;
 
     dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space, &bh);
     if (!dent) {
         da->nr_blocks = sdp->sd_max_dirres;
         if (!(ip->i_diskflags & GFS2_DIF_EXHASH) &&
             (GFS2_DIRENT_SIZE(name->len) < extra))
             da->nr_blocks = 1;
         return 0;
     }
     if (IS_ERR(dent))
         return PTR_ERR(dent);
 
     if (da->save_loc) {
         da->bh = bh;
         da->dent = dent;
     } else {
         brelse(bh);
     }
     return 0;
 }
 

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