stop using igrab in xfs_vn_link
[safe/jmp/linux-2.6] / fs / xfs / xfs_ialloc.c
index 1a5e3ff..e6ebbae 100644 (file)
 #include "xfs_error.h"
 #include "xfs_bmap.h"
 
+
 /*
- * Log specified fields for the inode given by bp and off.
+ * Allocation group level functions.
  */
-STATIC void
-xfs_ialloc_log_di(
-       xfs_trans_t     *tp,            /* transaction pointer */
-       xfs_buf_t       *bp,            /* inode buffer */
-       int             off,            /* index of inode in buffer */
-       int             fields)         /* bitmask of fields to log */
+static inline int
+xfs_ialloc_cluster_alignment(
+       xfs_alloc_arg_t *args)
 {
-       int                     first;          /* first byte number */
-       int                     ioffset;        /* off in bytes */
-       int                     last;           /* last byte number */
-       xfs_mount_t             *mp;            /* mount point structure */
-       static const short      offsets[] = {   /* field offsets */
-                                               /* keep in sync with bits */
-               offsetof(xfs_dinode_core_t, di_magic),
-               offsetof(xfs_dinode_core_t, di_mode),
-               offsetof(xfs_dinode_core_t, di_version),
-               offsetof(xfs_dinode_core_t, di_format),
-               offsetof(xfs_dinode_core_t, di_onlink),
-               offsetof(xfs_dinode_core_t, di_uid),
-               offsetof(xfs_dinode_core_t, di_gid),
-               offsetof(xfs_dinode_core_t, di_nlink),
-               offsetof(xfs_dinode_core_t, di_projid),
-               offsetof(xfs_dinode_core_t, di_pad),
-               offsetof(xfs_dinode_core_t, di_atime),
-               offsetof(xfs_dinode_core_t, di_mtime),
-               offsetof(xfs_dinode_core_t, di_ctime),
-               offsetof(xfs_dinode_core_t, di_size),
-               offsetof(xfs_dinode_core_t, di_nblocks),
-               offsetof(xfs_dinode_core_t, di_extsize),
-               offsetof(xfs_dinode_core_t, di_nextents),
-               offsetof(xfs_dinode_core_t, di_anextents),
-               offsetof(xfs_dinode_core_t, di_forkoff),
-               offsetof(xfs_dinode_core_t, di_aformat),
-               offsetof(xfs_dinode_core_t, di_dmevmask),
-               offsetof(xfs_dinode_core_t, di_dmstate),
-               offsetof(xfs_dinode_core_t, di_flags),
-               offsetof(xfs_dinode_core_t, di_gen),
-               offsetof(xfs_dinode_t, di_next_unlinked),
-               offsetof(xfs_dinode_t, di_u),
-               offsetof(xfs_dinode_t, di_a),
-               sizeof(xfs_dinode_t)
-       };
+       if (xfs_sb_version_hasalign(&args->mp->m_sb) &&
+           args->mp->m_sb.sb_inoalignmt >=
+            XFS_B_TO_FSBT(args->mp, XFS_INODE_CLUSTER_SIZE(args->mp)))
+               return args->mp->m_sb.sb_inoalignmt;
+       return 1;
+}
 
+/*
+ * Lookup the record equal to ino in the btree given by cur.
+ */
+STATIC int                             /* error */
+xfs_inobt_lookup_eq(
+       struct xfs_btree_cur    *cur,   /* btree cursor */
+       xfs_agino_t             ino,    /* starting inode of chunk */
+       __int32_t               fcnt,   /* free inode count */
+       xfs_inofree_t           free,   /* free inode mask */
+       int                     *stat)  /* success/failure */
+{
+       cur->bc_rec.i.ir_startino = ino;
+       cur->bc_rec.i.ir_freecount = fcnt;
+       cur->bc_rec.i.ir_free = free;
+       return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
+}
 
-       ASSERT(offsetof(xfs_dinode_t, di_core) == 0);
-       ASSERT((fields & (XFS_DI_U|XFS_DI_A)) == 0);
-       mp = tp->t_mountp;
-       /*
-        * Get the inode-relative first and last bytes for these fields
-        */
-       xfs_btree_offsets(fields, offsets, XFS_DI_NUM_BITS, &first, &last);
-       /*
-        * Convert to buffer offsets and log it.
-        */
-       ioffset = off << mp->m_sb.sb_inodelog;
-       first += ioffset;
-       last += ioffset;
-       xfs_trans_log_buf(tp, bp, first, last);
+/*
+ * Lookup the first record greater than or equal to ino
+ * in the btree given by cur.
+ */
+int                                    /* error */
+xfs_inobt_lookup_ge(
+       struct xfs_btree_cur    *cur,   /* btree cursor */
+       xfs_agino_t             ino,    /* starting inode of chunk */
+       __int32_t               fcnt,   /* free inode count */
+       xfs_inofree_t           free,   /* free inode mask */
+       int                     *stat)  /* success/failure */
+{
+       cur->bc_rec.i.ir_startino = ino;
+       cur->bc_rec.i.ir_freecount = fcnt;
+       cur->bc_rec.i.ir_free = free;
+       return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
 }
 
 /*
- * Allocation group level functions.
+ * Lookup the first record less than or equal to ino
+ * in the btree given by cur.
  */
+int                                    /* error */
+xfs_inobt_lookup_le(
+       struct xfs_btree_cur    *cur,   /* btree cursor */
+       xfs_agino_t             ino,    /* starting inode of chunk */
+       __int32_t               fcnt,   /* free inode count */
+       xfs_inofree_t           free,   /* free inode mask */
+       int                     *stat)  /* success/failure */
+{
+       cur->bc_rec.i.ir_startino = ino;
+       cur->bc_rec.i.ir_freecount = fcnt;
+       cur->bc_rec.i.ir_free = free;
+       return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
+}
+
+/*
+ * Update the record referred to by cur to the value given
+ * by [ino, fcnt, free].
+ * This either works (return 0) or gets an EFSCORRUPTED error.
+ */
+STATIC int                             /* error */
+xfs_inobt_update(
+       struct xfs_btree_cur    *cur,   /* btree cursor */
+       xfs_agino_t             ino,    /* starting inode of chunk */
+       __int32_t               fcnt,   /* free inode count */
+       xfs_inofree_t           free)   /* free inode mask */
+{
+       union xfs_btree_rec     rec;
+
+       rec.inobt.ir_startino = cpu_to_be32(ino);
+       rec.inobt.ir_freecount = cpu_to_be32(fcnt);
+       rec.inobt.ir_free = cpu_to_be64(free);
+       return xfs_btree_update(cur, &rec);
+}
+
+/*
+ * Get the data from the pointed-to record.
+ */
+int                                    /* error */
+xfs_inobt_get_rec(
+       struct xfs_btree_cur    *cur,   /* btree cursor */
+       xfs_agino_t             *ino,   /* output: starting inode of chunk */
+       __int32_t               *fcnt,  /* output: number of free inodes */
+       xfs_inofree_t           *free,  /* output: free inode mask */
+       int                     *stat)  /* output: success/failure */
+{
+       union xfs_btree_rec     *rec;
+       int                     error;
+
+       error = xfs_btree_get_rec(cur, &rec, stat);
+       if (!error && *stat == 1) {
+               *ino = be32_to_cpu(rec->inobt.ir_startino);
+               *fcnt = be32_to_cpu(rec->inobt.ir_freecount);
+               *free = be64_to_cpu(rec->inobt.ir_free);
+       }
+       return error;
+}
 
 /*
  * Allocate new inodes in the allocation group specified by agbp.
@@ -123,6 +167,7 @@ xfs_ialloc_ag_alloc(
        int             blks_per_cluster;  /* fs blocks per inode cluster */
        xfs_btree_cur_t *cur;           /* inode btree cursor */
        xfs_daddr_t     d;              /* disk addr of buffer */
+       xfs_agnumber_t  agno;
        int             error;
        xfs_buf_t       *fbuf;          /* new free inodes' buffer */
        xfs_dinode_t    *free;          /* new free inode structure */
@@ -136,6 +181,7 @@ xfs_ialloc_ag_alloc(
        int             version;        /* inode version number to use */
        int             isaligned = 0;  /* inode allocation at stripe unit */
                                        /* boundary */
+       unsigned int    gen;
 
        args.tp = tp;
        args.mp = tp->t_mountp;
@@ -166,10 +212,24 @@ xfs_ialloc_ag_alloc(
                args.mod = args.total = args.wasdel = args.isfl =
                        args.userdata = args.minalignslop = 0;
                args.prod = 1;
-               args.alignment = 1;
+
                /*
-                * Allow space for the inode btree to split.
+                * We need to take into account alignment here to ensure that
+                * we don't modify the free list if we fail to have an exact
+                * block. If we don't have an exact match, and every oher
+                * attempt allocation attempt fails, we'll end up cancelling
+                * a dirty transaction and shutting down.
+                *
+                * For an exact allocation, alignment must be 1,
+                * however we need to take cluster alignment into account when
+                * fixing up the freelist. Use the minalignslop field to
+                * indicate that extra blocks might be required for alignment,
+                * but not to use them in the actual exact allocation.
                 */
+               args.alignment = 1;
+               args.minalignslop = xfs_ialloc_cluster_alignment(&args) - 1;
+
+               /* Allow space for the inode btree to split. */
                args.minleft = XFS_IN_MAXLEVELS(args.mp) - 1;
                if ((error = xfs_alloc_vextent(&args)))
                        return error;
@@ -190,13 +250,8 @@ xfs_ialloc_ag_alloc(
                        ASSERT(!(args.mp->m_flags & XFS_MOUNT_NOALIGN));
                        args.alignment = args.mp->m_dalign;
                        isaligned = 1;
-               } else if (XFS_SB_VERSION_HASALIGN(&args.mp->m_sb) &&
-                          args.mp->m_sb.sb_inoalignmt >=
-                          XFS_B_TO_FSBT(args.mp,
-                               XFS_INODE_CLUSTER_SIZE(args.mp)))
-                               args.alignment = args.mp->m_sb.sb_inoalignmt;
-               else
-                       args.alignment = 1;
+               } else
+                       args.alignment = xfs_ialloc_cluster_alignment(&args);
                /*
                 * Need to figure out where to allocate the inode blocks.
                 * Ideally they should be spaced out through the a.g.
@@ -229,12 +284,7 @@ xfs_ialloc_ag_alloc(
                args.agbno = be32_to_cpu(agi->agi_root);
                args.fsbno = XFS_AGB_TO_FSB(args.mp,
                                be32_to_cpu(agi->agi_seqno), args.agbno);
-               if (XFS_SB_VERSION_HASALIGN(&args.mp->m_sb) &&
-                       args.mp->m_sb.sb_inoalignmt >=
-                       XFS_B_TO_FSBT(args.mp, XFS_INODE_CLUSTER_SIZE(args.mp)))
-                               args.alignment = args.mp->m_sb.sb_inoalignmt;
-               else
-                       args.alignment = 1;
+               args.alignment = xfs_ialloc_cluster_alignment(&args);
                if ((error = xfs_alloc_vextent(&args)))
                        return error;
        }
@@ -270,11 +320,19 @@ xfs_ialloc_ag_alloc(
         * use the old version so that old kernels will continue to be
         * able to use the file system.
         */
-       if (XFS_SB_VERSION_HASNLINK(&args.mp->m_sb))
-               version = XFS_DINODE_VERSION_2;
+       if (xfs_sb_version_hasnlink(&args.mp->m_sb))
+               version = 2;
        else
-               version = XFS_DINODE_VERSION_1;
+               version = 1;
 
+       /*
+        * Seed the new inode cluster with a random generation number. This
+        * prevents short-term reuse of generation numbers if a chunk is
+        * freed and then immediately reallocated. We use random numbers
+        * rather than a linear progression to prevent the next generation
+        * number from being easily guessable.
+        */
+       gen = random32();
        for (j = 0; j < nbufs; j++) {
                /*
                 * Get the block.
@@ -286,32 +344,39 @@ xfs_ialloc_ag_alloc(
                                         XFS_BUF_LOCK);
                ASSERT(fbuf);
                ASSERT(!XFS_BUF_GETERROR(fbuf));
+
                /*
-                * Set initial values for the inodes in this buffer.
+                * Initialize all inodes in this buffer and then log them.
+                *
+                * XXX: It would be much better if we had just one transaction to
+                *      log a whole cluster of inodes instead of all the indivdual
+                *      transactions causing a lot of log traffic.
                 */
                xfs_biozero(fbuf, 0, ninodes << args.mp->m_sb.sb_inodelog);
                for (i = 0; i < ninodes; i++) {
+                       int     ioffset = i << args.mp->m_sb.sb_inodelog;
+                       uint    isize = sizeof(struct xfs_dinode);
+
                        free = XFS_MAKE_IPTR(args.mp, fbuf, i);
-                       INT_SET(free->di_core.di_magic, ARCH_CONVERT, XFS_DINODE_MAGIC);
-                       INT_SET(free->di_core.di_version, ARCH_CONVERT, version);
-                       INT_SET(free->di_next_unlinked, ARCH_CONVERT, NULLAGINO);
-                       xfs_ialloc_log_di(tp, fbuf, i,
-                               XFS_DI_CORE_BITS | XFS_DI_NEXT_UNLINKED);
+                       free->di_magic = cpu_to_be16(XFS_DINODE_MAGIC);
+                       free->di_version = version;
+                       free->di_gen = cpu_to_be32(gen);
+                       free->di_next_unlinked = cpu_to_be32(NULLAGINO);
+                       xfs_trans_log_buf(tp, fbuf, ioffset, ioffset + isize - 1);
                }
                xfs_trans_inode_alloc_buf(tp, fbuf);
        }
-       be32_add(&agi->agi_count, newlen);
-       be32_add(&agi->agi_freecount, newlen);
+       be32_add_cpu(&agi->agi_count, newlen);
+       be32_add_cpu(&agi->agi_freecount, newlen);
+       agno = be32_to_cpu(agi->agi_seqno);
        down_read(&args.mp->m_peraglock);
-       args.mp->m_perag[be32_to_cpu(agi->agi_seqno)].pagi_freecount += newlen;
+       args.mp->m_perag[agno].pagi_freecount += newlen;
        up_read(&args.mp->m_peraglock);
        agi->agi_newino = cpu_to_be32(newino);
        /*
         * Insert records describing the new inode chunk into the btree.
         */
-       cur = xfs_btree_init_cursor(args.mp, tp, agbp,
-                       be32_to_cpu(agi->agi_seqno),
-                       XFS_BTNUM_INO, (xfs_inode_t *)0, 0);
+       cur = xfs_inobt_init_cursor(args.mp, tp, agbp, agno);
        for (thisino = newino;
             thisino < newino + newlen;
             thisino += XFS_INODES_PER_CHUNK) {
@@ -321,7 +386,7 @@ xfs_ialloc_ag_alloc(
                        return error;
                }
                ASSERT(i == 0);
-               if ((error = xfs_inobt_insert(cur, &i))) {
+               if ((error = xfs_btree_insert(cur, &i))) {
                        xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
                        return error;
                }
@@ -342,7 +407,7 @@ xfs_ialloc_ag_alloc(
        return 0;
 }
 
-STATIC __inline xfs_agnumber_t
+STATIC_INLINE xfs_agnumber_t
 xfs_ialloc_next_ag(
        xfs_mount_t     *mp)
 {
@@ -458,7 +523,7 @@ nextag:
                 */
                if (XFS_FORCED_SHUTDOWN(mp)) {
                        up_read(&mp->m_peraglock);
-                       return (xfs_buf_t *)0;
+                       return NULL;
                }
                agno++;
                if (agno >= agcount)
@@ -466,7 +531,7 @@ nextag:
                if (agno == pagno) {
                        if (flags == 0) {
                                up_read(&mp->m_peraglock);
-                               return (xfs_buf_t *)0;
+                               return NULL;
                        }
                        flags = 0;
                }
@@ -651,8 +716,7 @@ nextag:
         */
        agno = tagno;
        *IO_agbp = NULL;
-       cur = xfs_btree_init_cursor(mp, tp, agbp, be32_to_cpu(agi->agi_seqno),
-                                   XFS_BTNUM_INO, (xfs_inode_t *)0, 0);
+       cur = xfs_inobt_init_cursor(mp, tp, agbp, be32_to_cpu(agi->agi_seqno));
        /*
         * If pagino is 0 (this is the root inode allocation) use newino.
         * This must work because we've just allocated some.
@@ -672,7 +736,7 @@ nextag:
                                goto error0;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
                        freecount += rec.ir_freecount;
-                       if ((error = xfs_inobt_increment(cur, 0, &i)))
+                       if ((error = xfs_btree_increment(cur, 0, &i)))
                                goto error0;
                } while (i == 1);
 
@@ -716,7 +780,7 @@ nextag:
                        /*
                         * Search left with tcur, back up 1 record.
                         */
-                       if ((error = xfs_inobt_decrement(tcur, 0, &i)))
+                       if ((error = xfs_btree_decrement(tcur, 0, &i)))
                                goto error1;
                        doneleft = !i;
                        if (!doneleft) {
@@ -730,7 +794,7 @@ nextag:
                        /*
                         * Search right with cur, go forward 1 record.
                         */
-                       if ((error = xfs_inobt_increment(cur, 0, &i)))
+                       if ((error = xfs_btree_increment(cur, 0, &i)))
                                goto error1;
                        doneright = !i;
                        if (!doneright) {
@@ -792,7 +856,7 @@ nextag:
                                 * further left.
                                 */
                                if (useleft) {
-                                       if ((error = xfs_inobt_decrement(tcur, 0,
+                                       if ((error = xfs_btree_decrement(tcur, 0,
                                                        &i)))
                                                goto error1;
                                        doneleft = !i;
@@ -812,7 +876,7 @@ nextag:
                                 * further right.
                                 */
                                else {
-                                       if ((error = xfs_inobt_increment(cur, 0,
+                                       if ((error = xfs_btree_increment(cur, 0,
                                                        &i)))
                                                goto error1;
                                        doneright = !i;
@@ -867,7 +931,7 @@ nextag:
                                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
                                if (rec.ir_freecount > 0)
                                        break;
-                               if ((error = xfs_inobt_increment(cur, 0, &i)))
+                               if ((error = xfs_btree_increment(cur, 0, &i)))
                                        goto error0;
                                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
                        }
@@ -884,7 +948,7 @@ nextag:
        if ((error = xfs_inobt_update(cur, rec.ir_startino, rec.ir_freecount,
                        rec.ir_free)))
                goto error0;
-       be32_add(&agi->agi_freecount, -1);
+       be32_add_cpu(&agi->agi_freecount, -1);
        xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
        down_read(&mp->m_peraglock);
        mp->m_perag[tagno].pagi_freecount--;
@@ -901,7 +965,7 @@ nextag:
                                goto error0;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
                        freecount += rec.ir_freecount;
-                       if ((error = xfs_inobt_increment(cur, 0, &i)))
+                       if ((error = xfs_btree_increment(cur, 0, &i)))
                                goto error0;
                } while (i == 1);
                ASSERT(freecount == be32_to_cpu(agi->agi_freecount) ||
@@ -997,8 +1061,7 @@ xfs_difree(
        /*
         * Initialize the cursor.
         */
-       cur = xfs_btree_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_INO,
-               (xfs_inode_t *)0, 0);
+       cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
 #ifdef DEBUG
        if (cur->bc_nlevels == 1) {
                int freecount = 0;
@@ -1011,7 +1074,7 @@ xfs_difree(
                                goto error0;
                        if (i) {
                                freecount += rec.ir_freecount;
-                               if ((error = xfs_inobt_increment(cur, 0, &i)))
+                               if ((error = xfs_btree_increment(cur, 0, &i)))
                                        goto error0;
                        }
                } while (i == 1);
@@ -1052,7 +1115,7 @@ xfs_difree(
        /*
         * When an inode cluster is free, it becomes eligible for removal
         */
-       if ((mp->m_flags & XFS_MOUNT_IDELETE) &&
+       if (!(mp->m_flags & XFS_MOUNT_IKEEP) &&
            (rec.ir_freecount == XFS_IALLOC_INODES(mp))) {
 
                *delete = 1;
@@ -1064,8 +1127,8 @@ xfs_difree(
                 * to be freed when the transaction is committed.
                 */
                ilen = XFS_IALLOC_INODES(mp);
-               be32_add(&agi->agi_count, -ilen);
-               be32_add(&agi->agi_freecount, -(ilen - 1));
+               be32_add_cpu(&agi->agi_count, -ilen);
+               be32_add_cpu(&agi->agi_freecount, -(ilen - 1));
                xfs_ialloc_log_agi(tp, agbp, XFS_AGI_COUNT | XFS_AGI_FREECOUNT);
                down_read(&mp->m_peraglock);
                mp->m_perag[agno].pagi_freecount -= ilen - 1;
@@ -1073,8 +1136,8 @@ xfs_difree(
                xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, -ilen);
                xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));
 
-               if ((error = xfs_inobt_delete(cur, &i))) {
-                       cmn_err(CE_WARN, "xfs_difree: xfs_inobt_delete returned an error %d on %s.\n",
+               if ((error = xfs_btree_delete(cur, &i))) {
+                       cmn_err(CE_WARN, "xfs_difree: xfs_btree_delete returned an error %d on %s.\n",
                                error, mp->m_fsname);
                        goto error0;
                }
@@ -1094,7 +1157,7 @@ xfs_difree(
                /* 
                 * Change the inode free counts and log the ag/sb changes.
                 */
-               be32_add(&agi->agi_freecount, 1);
+               be32_add_cpu(&agi->agi_freecount, 1);
                xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
                down_read(&mp->m_peraglock);
                mp->m_perag[agno].pagi_freecount++;
@@ -1116,7 +1179,7 @@ xfs_difree(
                                goto error0;
                        if (i) {
                                freecount += rec.ir_freecount;
-                               if ((error = xfs_inobt_increment(cur, 0, &i)))
+                               if ((error = xfs_btree_increment(cur, 0, &i)))
                                        goto error0;
                        }
                } while (i == 1);
@@ -1133,36 +1196,28 @@ error0:
 }
 
 /*
- * Return the location of the inode in bno/off, for mapping it into a buffer.
+ * Return the location of the inode in imap, for mapping it into a buffer.
  */
-/*ARGSUSED*/
 int
-xfs_dilocate(
-       xfs_mount_t     *mp,    /* file system mount structure */
-       xfs_trans_t     *tp,    /* transaction pointer */
+xfs_imap(
+       xfs_mount_t      *mp,   /* file system mount structure */
+       xfs_trans_t      *tp,   /* transaction pointer */
        xfs_ino_t       ino,    /* inode to locate */
-       xfs_fsblock_t   *bno,   /* output: block containing inode */
-       int             *len,   /* output: num blocks in inode cluster */
-       int             *off,   /* output: index in block of inode */
-       uint            flags)  /* flags concerning inode lookup */
+       struct xfs_imap *imap,  /* location map structure */
+       uint            flags)  /* flags for inode btree lookup */
 {
        xfs_agblock_t   agbno;  /* block number of inode in the alloc group */
-       xfs_buf_t       *agbp;  /* agi buffer */
        xfs_agino_t     agino;  /* inode number within alloc group */
        xfs_agnumber_t  agno;   /* allocation group number */
        int             blks_per_cluster; /* num blocks per inode cluster */
        xfs_agblock_t   chunk_agbno;    /* first block in inode chunk */
-       xfs_agino_t     chunk_agino;    /* first agino in inode chunk */
-       __int32_t       chunk_cnt;      /* count of free inodes in chunk */
-       xfs_inofree_t   chunk_free;     /* mask of free inodes in chunk */
        xfs_agblock_t   cluster_agbno;  /* first block in inode cluster */
-       xfs_btree_cur_t *cur;   /* inode btree cursor */
        int             error;  /* error code */
-       int             i;      /* temp state */
        int             offset; /* index of inode in its buffer */
        int             offset_agbno;   /* blks from chunk start to inode */
 
        ASSERT(ino != NULLFSINO);
+
        /*
         * Split up the inode number into its parts.
         */
@@ -1173,90 +1228,115 @@ xfs_dilocate(
            ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
 #ifdef DEBUG
                /* no diagnostics for bulkstat, ino comes from userspace */
-               if (flags & XFS_IMAP_BULKSTAT)
+               if (flags & XFS_IGET_BULKSTAT)
                        return XFS_ERROR(EINVAL);
                if (agno >= mp->m_sb.sb_agcount) {
                        xfs_fs_cmn_err(CE_ALERT, mp,
-                                       "xfs_dilocate: agno (%d) >= "
+                                       "xfs_imap: agno (%d) >= "
                                        "mp->m_sb.sb_agcount (%d)",
                                        agno,  mp->m_sb.sb_agcount);
                }
                if (agbno >= mp->m_sb.sb_agblocks) {
                        xfs_fs_cmn_err(CE_ALERT, mp,
-                                       "xfs_dilocate: agbno (0x%llx) >= "
+                                       "xfs_imap: agbno (0x%llx) >= "
                                        "mp->m_sb.sb_agblocks (0x%lx)",
                                        (unsigned long long) agbno,
                                        (unsigned long) mp->m_sb.sb_agblocks);
                }
                if (ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
                        xfs_fs_cmn_err(CE_ALERT, mp,
-                                       "xfs_dilocate: ino (0x%llx) != "
+                                       "xfs_imap: ino (0x%llx) != "
                                        "XFS_AGINO_TO_INO(mp, agno, agino) "
                                        "(0x%llx)",
                                        ino, XFS_AGINO_TO_INO(mp, agno, agino));
                }
+               xfs_stack_trace();
 #endif /* DEBUG */
                return XFS_ERROR(EINVAL);
        }
-       if ((mp->m_sb.sb_blocksize >= XFS_INODE_CLUSTER_SIZE(mp)) ||
-           !(flags & XFS_IMAP_LOOKUP)) {
+
+       /*
+        * If the inode cluster size is the same as the blocksize or
+        * smaller we get to the buffer by simple arithmetics.
+        */
+       if (XFS_INODE_CLUSTER_SIZE(mp) <= mp->m_sb.sb_blocksize) {
                offset = XFS_INO_TO_OFFSET(mp, ino);
                ASSERT(offset < mp->m_sb.sb_inopblock);
-               *bno = XFS_AGB_TO_FSB(mp, agno, agbno);
-               *off = offset;
-               *len = 1;
+
+               imap->im_blkno = XFS_AGB_TO_DADDR(mp, agno, agbno);
+               imap->im_len = XFS_FSB_TO_BB(mp, 1);
+               imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
                return 0;
        }
+
        blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_blocklog;
-       if (*bno != NULLFSBLOCK) {
+
+       /*
+        * If we get a block number passed from bulkstat we can use it to
+        * find the buffer easily.
+        */
+       if (imap->im_blkno) {
                offset = XFS_INO_TO_OFFSET(mp, ino);
                ASSERT(offset < mp->m_sb.sb_inopblock);
-               cluster_agbno = XFS_FSB_TO_AGBNO(mp, *bno);
-               *off = ((agbno - cluster_agbno) * mp->m_sb.sb_inopblock) +
-                       offset;
-               *len = blks_per_cluster;
+
+               cluster_agbno = XFS_DADDR_TO_AGBNO(mp, imap->im_blkno);
+               offset += (agbno - cluster_agbno) * mp->m_sb.sb_inopblock;
+
+               imap->im_len = XFS_FSB_TO_BB(mp, blks_per_cluster);
+               imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
                return 0;
        }
+
+       /*
+        * If the inode chunks are aligned then use simple maths to
+        * find the location. Otherwise we have to do a btree
+        * lookup to find the location.
+        */
        if (mp->m_inoalign_mask) {
                offset_agbno = agbno & mp->m_inoalign_mask;
                chunk_agbno = agbno - offset_agbno;
        } else {
+               xfs_btree_cur_t *cur;   /* inode btree cursor */
+               xfs_agino_t     chunk_agino; /* first agino in inode chunk */
+               __int32_t       chunk_cnt; /* count of free inodes in chunk */
+               xfs_inofree_t   chunk_free; /* mask of free inodes in chunk */
+               xfs_buf_t       *agbp;  /* agi buffer */
+               int             i;      /* temp state */
+
                down_read(&mp->m_peraglock);
                error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
                up_read(&mp->m_peraglock);
                if (error) {
-#ifdef DEBUG
-                       xfs_fs_cmn_err(CE_ALERT, mp, "xfs_dilocate: "
+                       xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
                                        "xfs_ialloc_read_agi() returned "
                                        "error %d, agno %d",
                                        error, agno);
-#endif /* DEBUG */
                        return error;
                }
-               cur = xfs_btree_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_INO,
-                       (xfs_inode_t *)0, 0);
-               if ((error = xfs_inobt_lookup_le(cur, agino, 0, 0, &i))) {
-#ifdef DEBUG
-                       xfs_fs_cmn_err(CE_ALERT, mp, "xfs_dilocate: "
+
+               cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
+               error = xfs_inobt_lookup_le(cur, agino, 0, 0, &i);
+               if (error) {
+                       xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
                                        "xfs_inobt_lookup_le() failed");
-#endif /* DEBUG */
                        goto error0;
                }
-               if ((error = xfs_inobt_get_rec(cur, &chunk_agino, &chunk_cnt,
-                               &chunk_free, &i))) {
-#ifdef DEBUG
-                       xfs_fs_cmn_err(CE_ALERT, mp, "xfs_dilocate: "
+
+               error = xfs_inobt_get_rec(cur, &chunk_agino, &chunk_cnt,
+                               &chunk_free, &i);
+               if (error) {
+                       xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
                                        "xfs_inobt_get_rec() failed");
-#endif /* DEBUG */
                        goto error0;
                }
                if (i == 0) {
 #ifdef DEBUG
-                       xfs_fs_cmn_err(CE_ALERT, mp, "xfs_dilocate: "
+                       xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
                                        "xfs_inobt_get_rec() failed");
 #endif /* DEBUG */
                        error = XFS_ERROR(EINVAL);
                }
+ error0:
                xfs_trans_brelse(tp, agbp);
                xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
                if (error)
@@ -1264,19 +1344,35 @@ xfs_dilocate(
                chunk_agbno = XFS_AGINO_TO_AGBNO(mp, chunk_agino);
                offset_agbno = agbno - chunk_agbno;
        }
+
        ASSERT(agbno >= chunk_agbno);
        cluster_agbno = chunk_agbno +
                ((offset_agbno / blks_per_cluster) * blks_per_cluster);
        offset = ((agbno - cluster_agbno) * mp->m_sb.sb_inopblock) +
                XFS_INO_TO_OFFSET(mp, ino);
-       *bno = XFS_AGB_TO_FSB(mp, agno, cluster_agbno);
-       *off = offset;
-       *len = blks_per_cluster;
+
+       imap->im_blkno = XFS_AGB_TO_DADDR(mp, agno, cluster_agbno);
+       imap->im_len = XFS_FSB_TO_BB(mp, blks_per_cluster);
+       imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
+
+       /*
+        * If the inode number maps to a block outside the bounds
+        * of the file system then return NULL rather than calling
+        * read_buf and panicing when we get an error from the
+        * driver.
+        */
+       if ((imap->im_blkno + imap->im_len) >
+           XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)) {
+               xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
+                       "(imap->im_blkno (0x%llx) + imap->im_len (0x%llx)) > "
+                       " XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) (0x%llx)",
+                       (unsigned long long) imap->im_blkno,
+                       (unsigned long long) imap->im_len,
+                       XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks));
+               return XFS_ERROR(EINVAL);
+       }
+
        return 0;
-error0:
-       xfs_trans_brelse(tp, agbp);
-       xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-       return error;
 }
 
 /*
@@ -1344,68 +1440,114 @@ xfs_ialloc_log_agi(
        xfs_trans_log_buf(tp, bp, first, last);
 }
 
+#ifdef DEBUG
+STATIC void
+xfs_check_agi_unlinked(
+       struct xfs_agi          *agi)
+{
+       int                     i;
+
+       for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++)
+               ASSERT(agi->agi_unlinked[i]);
+}
+#else
+#define xfs_check_agi_unlinked(agi)
+#endif
+
 /*
  * Read in the allocation group header (inode allocation section)
  */
 int
-xfs_ialloc_read_agi(
-       xfs_mount_t     *mp,            /* file system mount structure */
-       xfs_trans_t     *tp,            /* transaction pointer */
-       xfs_agnumber_t  agno,           /* allocation group number */
-       xfs_buf_t       **bpp)          /* allocation group hdr buf */
+xfs_read_agi(
+       struct xfs_mount        *mp,    /* file system mount structure */
+       struct xfs_trans        *tp,    /* transaction pointer */
+       xfs_agnumber_t          agno,   /* allocation group number */
+       struct xfs_buf          **bpp)  /* allocation group hdr buf */
 {
-       xfs_agi_t       *agi;           /* allocation group header */
-       int             agi_ok;         /* agi is consistent */
-       xfs_buf_t       *bp;            /* allocation group hdr buf */
-       xfs_perag_t     *pag;           /* per allocation group data */
-       int             error;
+       struct xfs_agi          *agi;   /* allocation group header */
+       int                     agi_ok; /* agi is consistent */
+       int                     error;
 
        ASSERT(agno != NULLAGNUMBER);
-       error = xfs_trans_read_buf(
-                       mp, tp, mp->m_ddev_targp,
+
+       error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
                        XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
-                       XFS_FSS_TO_BB(mp, 1), 0, &bp);
+                       XFS_FSS_TO_BB(mp, 1), 0, bpp);
        if (error)
                return error;
-       ASSERT(bp && !XFS_BUF_GETERROR(bp));
+
+       ASSERT(*bpp && !XFS_BUF_GETERROR(*bpp));
+       agi = XFS_BUF_TO_AGI(*bpp);
 
        /*
         * Validate the magic number of the agi block.
         */
-       agi = XFS_BUF_TO_AGI(bp);
-       agi_ok =
-               be32_to_cpu(agi->agi_magicnum) == XFS_AGI_MAGIC &&
-               XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum));
+       agi_ok = be32_to_cpu(agi->agi_magicnum) == XFS_AGI_MAGIC &&
+               XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum)) &&
+               be32_to_cpu(agi->agi_seqno) == agno;
        if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,
                        XFS_RANDOM_IALLOC_READ_AGI))) {
-               XFS_CORRUPTION_ERROR("xfs_ialloc_read_agi", XFS_ERRLEVEL_LOW,
+               XFS_CORRUPTION_ERROR("xfs_read_agi", XFS_ERRLEVEL_LOW,
                                     mp, agi);
-               xfs_trans_brelse(tp, bp);
+               xfs_trans_brelse(tp, *bpp);
                return XFS_ERROR(EFSCORRUPTED);
        }
+
+       XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_AGI, XFS_AGI_REF);
+
+       xfs_check_agi_unlinked(agi);
+       return 0;
+}
+
+int
+xfs_ialloc_read_agi(
+       struct xfs_mount        *mp,    /* file system mount structure */
+       struct xfs_trans        *tp,    /* transaction pointer */
+       xfs_agnumber_t          agno,   /* allocation group number */
+       struct xfs_buf          **bpp)  /* allocation group hdr buf */
+{
+       struct xfs_agi          *agi;   /* allocation group header */
+       struct xfs_perag        *pag;   /* per allocation group data */
+       int                     error;
+
+       error = xfs_read_agi(mp, tp, agno, bpp);
+       if (error)
+               return error;
+
+       agi = XFS_BUF_TO_AGI(*bpp);
        pag = &mp->m_perag[agno];
+
        if (!pag->pagi_init) {
                pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
+               pag->pagi_count = be32_to_cpu(agi->agi_count);
                pag->pagi_init = 1;
-       } else {
-               /*
-                * It's possible for these to be out of sync if
-                * we are in the middle of a forced shutdown.
-                */
-               ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
-                       XFS_FORCED_SHUTDOWN(mp));
        }
 
-#ifdef DEBUG
-       {
-               int     i;
+       /*
+        * It's possible for these to be out of sync if
+        * we are in the middle of a forced shutdown.
+        */
+       ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
+               XFS_FORCED_SHUTDOWN(mp));
+       return 0;
+}
 
-               for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++)
-                       ASSERT(agi->agi_unlinked[i]);
-       }
-#endif
+/*
+ * Read in the agi to initialise the per-ag data in the mount structure
+ */
+int
+xfs_ialloc_pagi_init(
+       xfs_mount_t     *mp,            /* file system mount structure */
+       xfs_trans_t     *tp,            /* transaction pointer */
+       xfs_agnumber_t  agno)           /* allocation group number */
+{
+       xfs_buf_t       *bp = NULL;
+       int             error;
 
-       XFS_BUF_SET_VTYPE_REF(bp, B_FS_AGI, XFS_AGI_REF);
-       *bpp = bp;
+       error = xfs_ialloc_read_agi(mp, tp, agno, &bp);
+       if (error)
+               return error;
+       if (bp)
+               xfs_trans_brelse(tp, bp);
        return 0;
 }