[XFS] merge xfs_imap into xfs_dilocate

xfs_imap is the only caller of xfs_dilocate and doesn't add any significant
value.  Merge the two functions and document the various cases we have for
inode cluster lookup in the new xfs_imap.

Also remove the unused im_agblkno and im_ioffset fields from struct xfs_imap
while we're at it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>

1 files changed, 82 insertions, 47 deletions

diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index 0ce56d6a4922..348ac30174c5 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -40,6 +40,7 @@
 #include "xfs_rtalloc.h"
 #include "xfs_error.h"
 #include "xfs_bmap.h"
+#include "xfs_imap.h"
 
 
 /*
@@ -1196,36 +1197,28 @@ 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.
          */
@@ -1240,20 +1233,20 @@ xfs_dilocate(
                         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));
@@ -1262,63 +1255,89 @@ xfs_dilocate(
 #endif /* DEBUG */
                 return XFS_ERROR(EINVAL);
         }
-        if ((mp->m_sb.sb_blocksize >= XFS_INODE_CLUSTER_SIZE(mp))) {
+
+        /*
+         * 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_inobt_init_cursor(mp, tp, agbp, agno);
-                if ((error = xfs_inobt_lookup_le(cur, agino, 0, 0, &i))) {
-#ifdef DEBUG
-                        xfs_fs_cmn_err(CE_ALERT, mp, "xfs_dilocate: "
+                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)
@@ -1326,19 +1345,35 @@ 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;
 }
 
 /*