xfs: bulkstat main loop logic is a mess

There are a bunch of variables tha tare more wildy scoped than they
need to be, obfuscated user buffer checks and tortured "next inode"
tracking. This all needs cleaning up to expose the real issues that
need fixing.

cc: <stable@vger.kernel.org> # 3.17
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index 7ea2b11..acae335 100644 (file)
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -348,30 +348,23 @@ xfs_bulkstat(
        xfs_agino_t             agino;  /* inode # in allocation group */
        xfs_agnumber_t          agno;   /* allocation group number */
        xfs_btree_cur_t         *cur;   /* btree cursor for ialloc btree */
-       int                     end_of_ag; /* set if we've seen the ag end */
-       int                     error;  /* error code */
-       int                     icount; /* count of inodes good in irbuf */
        size_t                  irbsize; /* size of irec buffer in bytes */
-       xfs_ino_t               ino;    /* inode number (filesystem) */
-       xfs_inobt_rec_incore_t  *irbp;  /* current irec buffer pointer */
        xfs_inobt_rec_incore_t  *irbuf; /* start of irec buffer */
-       xfs_inobt_rec_incore_t  *irbufend; /* end of good irec buffer entries */
        xfs_ino_t               lastino; /* last inode number returned */
        int                     nirbuf; /* size of irbuf */
        int                     rval;   /* return value error code */
        int                     ubcount; /* size of user's buffer */
-       int                     stat;
        struct xfs_bulkstat_agichunk ac;
+       int                     error = 0;
 
        /*
         * Get the last inode value, see if there's nothing to do.
         */
-       ino = (xfs_ino_t)*lastinop;
-       lastino = ino;
-       agno = XFS_INO_TO_AGNO(mp, ino);
-       agino = XFS_INO_TO_AGINO(mp, ino);
+       lastino = *lastinop;
+       agno = XFS_INO_TO_AGNO(mp, lastino);
+       agino = XFS_INO_TO_AGINO(mp, lastino);
        if (agno >= mp->m_sb.sb_agcount ||
-           ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
+           lastino != XFS_AGINO_TO_INO(mp, agno, agino)) {
                *done = 1;
                *ubcountp = 0;
                return 0;
@@ -396,8 +389,13 @@ xfs_bulkstat(
         * inode returned; 0 means start of the allocation group.
         */
        rval = 0;
-       while (XFS_BULKSTAT_UBLEFT(ac.ac_ubleft) && agno < mp->m_sb.sb_agcount) {
-               cond_resched();
+       while (agno < mp->m_sb.sb_agcount) {
+               struct xfs_inobt_rec_incore     *irbp = irbuf;
+               struct xfs_inobt_rec_incore     *irbufend = irbuf + nirbuf;
+               bool                            end_of_ag = false;
+               int                             icount = 0;
+               int                             stat;
+
                error = xfs_ialloc_read_agi(mp, NULL, agno, &agbp);
                if (error)
                        break;
@@ -407,10 +405,6 @@ xfs_bulkstat(
                 */
                cur = xfs_inobt_init_cursor(mp, NULL, agbp, agno,
                                            XFS_BTNUM_INO);
-               irbp = irbuf;
-               irbufend = irbuf + nirbuf;
-               end_of_ag = 0;
-               icount = 0;
                if (agino > 0) {
                        /*
                         * In the middle of an allocation group, we need to get
@@ -435,7 +429,7 @@ xfs_bulkstat(
                        error = xfs_inobt_lookup(cur, 0, XFS_LOOKUP_GE, &stat);
                }
                if (error || stat == 0) {
-                       end_of_ag = 1;
+                       end_of_ag = true;
                        goto del_cursor;
                }
 
@@ -448,7 +442,7 @@ xfs_bulkstat(
 
                        error = xfs_inobt_get_rec(cur, &r, &stat);
                        if (error || stat == 0) {
-                               end_of_ag = 1;
+                               end_of_ag = true;
                                goto del_cursor;
                        }
 
@@ -470,7 +464,7 @@ xfs_bulkstat(
                        agino = r.ir_startino + XFS_INODES_PER_CHUNK;
                        error = xfs_btree_increment(cur, 0, &stat);
                        if (error || stat == 0) {
-                               end_of_ag = 1;
+                               end_of_ag = true;
                                goto del_cursor;
                        }
                        cond_resched();
@@ -491,7 +485,7 @@ del_cursor:
                 */
                irbufend = irbp;
                for (irbp = irbuf;
-                    irbp < irbufend && XFS_BULKSTAT_UBLEFT(ac.ac_ubleft);
+                    irbp < irbufend && ac.ac_ubleft >= statstruct_size;
                     irbp++) {
                        error = xfs_bulkstat_ag_ichunk(mp, agno, irbp,
                                        formatter, statstruct_size, &ac,
@@ -502,17 +496,15 @@ del_cursor:
                        cond_resched();
                }
 
-               /*
-                * Set up for the next loop iteration.
-                */
-               if (XFS_BULKSTAT_UBLEFT(ac.ac_ubleft)) {
-                       if (end_of_ag) {
-                               agno++;
-                               agino = 0;
-                       } else
-                               agino = XFS_INO_TO_AGINO(mp, lastino);
-               } else
+               /* If we've run out of space, we are done */
+               if (ac.ac_ubleft < statstruct_size)
                        break;
+
+               if (end_of_ag) {
+                       agno++;
+                       agino = 0;
+               } else
+                       agino = XFS_INO_TO_AGINO(mp, lastino);
        }
        /*
         * Done, we're either out of filesystem or space to put the data.