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[PATCH 4/5] XFS: fix spurious uninitialised variable warning in xfs_grow

To: xfs@xxxxxxxxxxx
Subject: [PATCH 4/5] XFS: fix spurious uninitialised variable warning in xfs_growfs_rt
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Fri, 31 Oct 2008 12:15:28 +1100
In-reply-to: <1225415729-26514-1-git-send-email-david@xxxxxxxxxxxxx>
References: <1225415729-26514-1-git-send-email-david@xxxxxxxxxxxxx>
gcc is warning about an uninitialised variable in xfs_growfs_rt().
This is a false positive. Fix it by changing the scope of the
transaction pointer to wholly within the internal loop inside
the function.

While there, preemptively change xfs_growfs_rt_alloc() in the
same way as it has exactly the same structure as xfs_growfs_rt()
but gcc is not warning about it. Yet.

Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
---
 fs/xfs/xfs_rtalloc.c |   39 ++++++++++++++++++---------------------
 1 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index e2f68de..f18b9b2 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -85,7 +85,6 @@ xfs_growfs_rt_alloc(
 {
        xfs_fileoff_t   bno;            /* block number in file */
        xfs_buf_t       *bp;            /* temporary buffer for zeroing */
-       int             cancelflags;    /* flags for xfs_trans_cancel */
        int             committed;      /* transaction committed flag */
        xfs_daddr_t     d;              /* disk block address */
        int             error;          /* error return value */
@@ -96,15 +95,16 @@ xfs_growfs_rt_alloc(
        xfs_bmbt_irec_t map;            /* block map output */
        int             nmap;           /* number of block maps */
        int             resblks;        /* space reservation */
-       xfs_trans_t     *tp;            /* transaction pointer */
 
        /*
         * Allocate space to the file, as necessary.
         */
        while (oblocks < nblocks) {
+               int             cancelflags = 0;
+               xfs_trans_t     *tp;
+
                tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_ALLOC);
                resblks = XFS_GROWFSRT_SPACE_RES(mp, nblocks - oblocks);
-               cancelflags = 0;
                /*
                 * Reserve space & log for one extent added to the file.
                 */
@@ -171,7 +171,9 @@ xfs_growfs_rt_alloc(
                                mp->m_bsize, 0);
                        if (bp == NULL) {
                                error = XFS_ERROR(EIO);
-                               goto error_cancel;
+error_cancel:
+                               xfs_trans_cancel(tp, cancelflags);
+                               goto error;
                        }
                        memset(XFS_BUF_PTR(bp), 0, mp->m_sb.sb_blocksize);
                        xfs_trans_log_buf(tp, bp, 0, mp->m_sb.sb_blocksize - 1);
@@ -188,8 +190,6 @@ xfs_growfs_rt_alloc(
                oblocks = map.br_startoff + map.br_blockcount;
        }
        return 0;
-error_cancel:
-       xfs_trans_cancel(tp, cancelflags);
 error:
        return error;
 }
@@ -1856,7 +1856,6 @@ xfs_growfs_rt(
 {
        xfs_rtblock_t   bmbno;          /* bitmap block number */
        xfs_buf_t       *bp;            /* temporary buffer */
-       int             cancelflags;    /* flags for xfs_trans_cancel */
        int             error;          /* error return value */
        xfs_inode_t     *ip;            /* bitmap inode, used as lock */
        xfs_mount_t     *nmp;           /* new (fake) mount structure */
@@ -1872,10 +1871,8 @@ xfs_growfs_rt(
        xfs_extlen_t    rsumblocks;     /* current number of rt summary blks */
        xfs_sb_t        *sbp;           /* old superblock */
        xfs_fsblock_t   sumbno;         /* summary block number */
-       xfs_trans_t     *tp;            /* transaction pointer */
 
        sbp = &mp->m_sb;
-       cancelflags = 0;
        /*
         * Initial error checking.
         */
@@ -1942,6 +1939,9 @@ xfs_growfs_rt(
                     ((sbp->sb_rextents & ((1 << mp->m_blkbit_log) - 1)) != 0);
             bmbno < nrbmblocks;
             bmbno++) {
+               xfs_trans_t     *tp;
+               int             cancelflags = 0;
+
                *nmp = *mp;
                nsbp = &nmp->m_sb;
                /*
@@ -1967,16 +1967,15 @@ xfs_growfs_rt(
                 * Start a transaction, get the log reservation.
                 */
                tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_FREE);
-               cancelflags = 0;
                if ((error = xfs_trans_reserve(tp, 0,
                                XFS_GROWRTFREE_LOG_RES(nmp), 0, 0, 0)))
-                       break;
+                       goto error_cancel;
                /*
                 * Lock out other callers by grabbing the bitmap inode lock.
                 */
                if ((error = xfs_trans_iget(mp, tp, mp->m_sb.sb_rbmino, 0,
                                                XFS_ILOCK_EXCL, &ip)))
-                       break;
+                       goto error_cancel;
                ASSERT(ip == mp->m_rbmip);
                /*
                 * Update the bitmap inode's size.
@@ -1990,7 +1989,7 @@ xfs_growfs_rt(
                 */
                if ((error = xfs_trans_iget(mp, tp, mp->m_sb.sb_rsumino, 0,
                                                XFS_ILOCK_EXCL, &ip)))
-                       break;
+                       goto error_cancel;
                ASSERT(ip == mp->m_rsumip);
                /*
                 * Update the summary inode's size.
@@ -2005,7 +2004,7 @@ xfs_growfs_rt(
                    mp->m_rsumlevels != nmp->m_rsumlevels) {
                        error = xfs_rtcopy_summary(mp, nmp, tp);
                        if (error)
-                               break;
+                               goto error_cancel;
                }
                /*
                 * Update superblock fields.
@@ -2031,8 +2030,11 @@ xfs_growfs_rt(
                bp = NULL;
                error = xfs_rtfree_range(nmp, tp, sbp->sb_rextents,
                        nsbp->sb_rextents - sbp->sb_rextents, &bp, &sumbno);
-               if (error)
+               if (error) {
+error_cancel:
+                       xfs_trans_cancel(tp, cancelflags);
                        break;
+               }
                /*
                 * Mark more blocks free in the superblock.
                 */
@@ -2045,15 +2047,10 @@ xfs_growfs_rt(
                mp->m_rsumsize = nrsumsize;
 
                error = xfs_trans_commit(tp, 0);
-               if (error) {
-                       tp = NULL;
+               if (error)
                        break;
-               }
        }
 
-       if (error && tp)
-               xfs_trans_cancel(tp, cancelflags);
-
        /*
         * Free the fake mp structure.
         */
-- 
1.5.6.5

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