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[PATCH v3 04/10] xfs: fix error handling at xfs_inumbers

To: "xfs@xxxxxxxxxxx" <xfs@xxxxxxxxxxx>
Subject: [PATCH v3 04/10] xfs: fix error handling at xfs_inumbers
From: Jeff Liu <jeff.liu@xxxxxxxxxx>
Date: Tue, 03 Jun 2014 17:18:15 +0800
Delivered-to: xfs@xxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0
From: Jie Liu <jeff.liu@xxxxxxxxxx>

To fetch the file system number tables, we currently just ignore the
errors and proceed to loop over the next AG or bump agino to the next
chunk in case of btree operations failed, that is not properly because
those errors might hint us potential file system problems.

This patch rework xfs_inumbers() to handle the btree operation errors
as well as the loop conditions.

Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx>
---
 fs/xfs/xfs_itable.c | 91 ++++++++++++++++++++++-------------------------------
 1 file changed, 37 insertions(+), 54 deletions(-)

diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index dd68696..693e787 100644
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -550,61 +550,40 @@ xfs_inumbers(
 
        bcount = MIN(left, (int)(PAGE_SIZE / sizeof(*buffer)));
        buffer = kmem_alloc(bcount * sizeof(*buffer), KM_SLEEP);
-       while (left > 0 && agno < mp->m_sb.sb_agcount) {
+       do {
                struct xfs_inobt_rec_incore     r;
                int                             stat;
 
-               if (agbp == NULL) {
+               if (!agbp) {
                        error = xfs_ialloc_read_agi(mp, NULL, agno, &agbp);
-                       if (error) {
-                               /*
-                                * If we can't read the AGI of this ag,
-                                * then just skip to the next one.
-                                */
-                               ASSERT(cur == NULL);
-                               agbp = NULL;
-                               agno++;
-                               agino = 0;
-                               continue;
-                       }
+                       if (error)
+                               break;
+
                        cur = xfs_inobt_init_cursor(mp, NULL, agbp, agno,
                                                    XFS_BTNUM_INO);
                        error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_GE,
                                                 &stat);
-                       if (error) {
-                               xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-                               cur = NULL;
-                               xfs_buf_relse(agbp);
-                               agbp = NULL;
-                               /*
-                                * Move up the last inode in the current
-                                * chunk.  The lookup_ge will always get
-                                * us the first inode in the next chunk.
-                                */
-                               agino += XFS_INODES_PER_CHUNK - 1;
-                               continue;
-                       }
+                       if (error)
+                               break;
+                       if (!stat)
+                               goto next_ag;
                }
+
                error = xfs_inobt_get_rec(cur, &r, &stat);
-               if (error || stat == 0) {
-                       xfs_buf_relse(agbp);
-                       agbp = NULL;
-                       xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
-                       cur = NULL;
-                       agno++;
-                       agino = 0;
-                       continue;
-               }
+               if (error)
+                       break;
+               if (!stat)
+                       goto next_ag;
+
                agino = r.ir_startino + XFS_INODES_PER_CHUNK - 1;
                buffer[bufidx].xi_startino =
                        XFS_AGINO_TO_INO(mp, agno, r.ir_startino);
                buffer[bufidx].xi_alloccount =
                        XFS_INODES_PER_CHUNK - r.ir_freecount;
                buffer[bufidx].xi_allocmask = ~r.ir_free;
-               bufidx++;
-               left--;
-               if (bufidx == bcount) {
+               if (++bufidx == bcount) {
                        long written;
+
                        error = formatter(ubuffer, buffer, bufidx, &written);
                        if (error)
                                break;
@@ -612,22 +591,24 @@ xfs_inumbers(
                        *count += bufidx;
                        bufidx = 0;
                }
-               if (left) {
-                       error = xfs_btree_increment(cur, 0, &stat);
-                       if (error) {
-                               xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-                               cur = NULL;
-                               xfs_buf_relse(agbp);
-                               agbp = NULL;
-                               /*
-                                * The agino value has already been bumped.
-                                * Just try to skip up to it.
-                                */
-                               agino += XFS_INODES_PER_CHUNK;
-                               continue;
-                       }
-               }
-       }
+               if (--left)
+                       break;
+
+               error = xfs_btree_increment(cur, 0, &stat);
+               if (error)
+                       break;
+               if (stat)
+                       continue;
+
+next_ag:
+               xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
+               cur = NULL;
+               xfs_buf_relse(agbp);
+               agbp = NULL;
+               agno++;
+               agino = 0;
+       } while (++agno < mp->m_sb.sb_agcount);
+
        if (!error) {
                if (bufidx) {
                        long written;
@@ -638,11 +619,13 @@ xfs_inumbers(
                }
                *lastino = XFS_AGINO_TO_INO(mp, agno, agino);
        }
+
        kmem_free(buffer);
        if (cur)
                xfs_btree_del_cursor(cur, (error ? XFS_BTREE_ERROR :
                                           XFS_BTREE_NOERROR));
        if (agbp)
                xfs_buf_relse(agbp);
+
        return error;
 }
-- 
1.8.3.2

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