xfs
[Top] [All Lists]

Re: [PATCH 6/6] xfs: track bulkstat progress by agino

To: Dave Chinner <david@xxxxxxxxxxxxx>
Subject: Re: [PATCH 6/6] xfs: track bulkstat progress by agino
From: Brian Foster <bfoster@xxxxxxxxxx>
Date: Thu, 6 Nov 2014 11:32:21 -0500
Cc: xfs@xxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1415279699-8739-7-git-send-email-david@xxxxxxxxxxxxx>
References: <1415279699-8739-1-git-send-email-david@xxxxxxxxxxxxx> <1415279699-8739-7-git-send-email-david@xxxxxxxxxxxxx>
User-agent: Mutt/1.5.23 (2014-03-12)
On Fri, Nov 07, 2014 at 12:14:59AM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@xxxxxxxxxx>
> 
> The bulkstat main loop progress is tracked by the "lastino"
> variable, which is a full 64 bit inode. However, the loop actually
> works on agno/agino pairs, and so there's a significant disconnect
> between the rest of the loop and the main cursor. Convert this to
> use the agino, and pass the agino into the chunk formatting function
> and convert it too.
> 
> This gets rid of the inconsistency in the loop processing, and
> finally makes it simple for us to skip inodes at any point in the
> loop simply by incrementing the agino cursor.
> 
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> ---
>  fs/xfs/xfs_itable.c | 68 
> ++++++++++++++++++++++++++---------------------------
>  1 file changed, 34 insertions(+), 34 deletions(-)
> 
> diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
> index ff3f431..05e83a6 100644
> --- a/fs/xfs/xfs_itable.c
> +++ b/fs/xfs/xfs_itable.c
> @@ -282,30 +282,31 @@ xfs_bulkstat_ag_ichunk(
>       bulkstat_one_pf                 formatter,
>       size_t                          statstruct_size,
>       struct xfs_bulkstat_agichunk    *acp,
> -     xfs_ino_t                       *lastino)
> +     xfs_agino_t                     *last_agino)
>  {
>       char                            __user **ubufp = acp->ac_ubuffer;
>       int                             chunkidx;
>       int                             error = 0;
> -     xfs_agino_t                     agino;
> +     xfs_agino_t                     agino = irbp->ir_startino;
>  
> -     agino = irbp->ir_startino;
>       for (chunkidx = 0; chunkidx < XFS_INODES_PER_CHUNK;
>            chunkidx++, agino++) {
>               int             fmterror;
>               int             ubused;
> -             xfs_ino_t       ino = XFS_AGINO_TO_INO(mp, agno, agino);
> +
> +             /* inode won't fit in buffer, we are done */
> +             if (acp->ac_ubleft < statstruct_size)
> +                     break;
>  
>               /* Skip if this inode is free */
> -             if (XFS_INOBT_MASK(chunkidx) & irbp->ir_free) {
> -                     *lastino = ino;
> +             if (XFS_INOBT_MASK(chunkidx) & irbp->ir_free)
>                       continue;
> -             }
>  
>               /* Get the inode and fill in a single buffer */
>               ubused = statstruct_size;
> -             error = formatter(mp, ino, *ubufp, acp->ac_ubleft,
> -                               &ubused, &fmterror);
> +             error = formatter(mp, XFS_AGINO_TO_INO(mp, agno, agino),
> +                               *ubufp, acp->ac_ubleft, &ubused, &fmterror);
> +
>               if (fmterror == BULKSTAT_RV_GIVEUP ||
>                   (error && error != -ENOENT && error != -EINVAL)) {
>                       acp->ac_ubleft = 0;
> @@ -315,7 +316,6 @@ xfs_bulkstat_ag_ichunk(
>  
>               /* be careful not to leak error if at end of chunk */
>               if (fmterror == BULKSTAT_RV_NOTHING || error) {
> -                     *lastino = ino;
>                       error = 0;
>                       continue;
>               }
> @@ -323,12 +323,18 @@ xfs_bulkstat_ag_ichunk(
>               *ubufp += ubused;
>               acp->ac_ubleft -= ubused;
>               acp->ac_ubelem++;
> -             *lastino = ino;
> -
> -             if (acp->ac_ubleft < statstruct_size)
> -                     break;
>       }
>  
> +     /*
> +      * Post-update *last_agino. At this point, agino will always point one
> +      * inode past the last inode we processed successfully. Hence we
> +      * substract that inode when setting the *last_agino cursor so that we
> +      * return the correct cookie to userspace. On the next bulkstat call,
> +      * the inode under the lastino cookie will be skipped as we have already
> +      * processed it here.
> +      */
> +     *last_agino = agino - 1;
> +
>       return error;
>  }
>  
> @@ -352,7 +358,6 @@ xfs_bulkstat(
>       xfs_btree_cur_t         *cur;   /* btree cursor for ialloc btree */
>       size_t                  irbsize; /* size of irec buffer in bytes */
>       xfs_inobt_rec_incore_t  *irbuf; /* start of irec buffer */
> -     xfs_ino_t               lastino; /* last inode number returned */
>       int                     nirbuf; /* size of irbuf */
>       int                     ubcount; /* size of user's buffer */
>       struct xfs_bulkstat_agichunk ac;
> @@ -361,11 +366,10 @@ xfs_bulkstat(
>       /*
>        * Get the last inode value, see if there's nothing to do.
>        */
> -     lastino = *lastinop;
> -     agno = XFS_INO_TO_AGNO(mp, lastino);
> -     agino = XFS_INO_TO_AGINO(mp, lastino);
> +     agno = XFS_INO_TO_AGNO(mp, *lastinop);
> +     agino = XFS_INO_TO_AGINO(mp, *lastinop);
>       if (agno >= mp->m_sb.sb_agcount ||
> -         lastino != XFS_AGINO_TO_INO(mp, agno, agino)) {
> +         *lastinop != XFS_AGINO_TO_INO(mp, agno, agino)) {
>               *done = 1;
>               *ubcountp = 0;
>               return 0;
> @@ -420,7 +424,6 @@ xfs_bulkstat(
>                               irbp->ir_freecount = r.ir_freecount;
>                               irbp->ir_free = r.ir_free;
>                               irbp++;
> -                             agino = r.ir_startino + XFS_INODES_PER_CHUNK;
>                       }
>                       /* Increment to the next record */
>                       error = xfs_btree_increment(cur, 0, &stat);
> @@ -461,7 +464,6 @@ xfs_bulkstat(
>                       /*
>                        * Set agino to after this chunk and bump the cursor.
>                        */

This comment could be updated since it's not safe to set agino here any
longer. Other than that, this all looks pretty good to me now:

Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>

> -                     agino = r.ir_startino + XFS_INODES_PER_CHUNK;
>                       error = xfs_btree_increment(cur, 0, &stat);
>                       if (error || stat == 0) {
>                               end_of_ag = true;
> @@ -481,7 +483,9 @@ del_cursor:
>               if (error)
>                       break;
>               /*
> -              * Now format all the good inodes into the user's buffer.
> +              * Now format all the good inodes into the user's buffer. The
> +              * call to xfs_bulkstat_ag_ichunk() sets up the agino pointer
> +              * for the next loop iteration.
>                */
>               irbufend = irbp;
>               for (irbp = irbuf;
> @@ -489,7 +493,7 @@ del_cursor:
>                    irbp++) {
>                       error = xfs_bulkstat_ag_ichunk(mp, agno, irbp,
>                                       formatter, statstruct_size, &ac,
> -                                     &lastino);
> +                                     &agino);
>                       if (error)
>                               break;
>  
> @@ -506,8 +510,7 @@ del_cursor:
>               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.
> @@ -525,16 +528,13 @@ del_cursor:
>       if (ac.ac_ubelem)
>               error = 0;
>  
> -     if (agno >= mp->m_sb.sb_agcount) {
> -             /*
> -              * If we ran out of filesystem, mark lastino as off
> -              * the end of the filesystem, so the next call
> -              * will return immediately.
> -              */
> -             *lastinop = (xfs_ino_t)XFS_AGINO_TO_INO(mp, agno, 0);
> +     /*
> +      * If we ran out of filesystem, lastino will point off the end of
> +      * the filesystem so the next call will return immediately.
> +      */
> +     *lastinop = XFS_AGINO_TO_INO(mp, agno, agino);
> +     if (agno >= mp->m_sb.sb_agcount)
>               *done = 1;
> -     } else
> -             *lastinop = (xfs_ino_t)lastino;
>  
>       return error;
>  }
> -- 
> 2.0.0
> 
> _______________________________________________
> xfs mailing list
> xfs@xxxxxxxxxxx
> http://oss.sgi.com/mailman/listinfo/xfs

<Prev in Thread] Current Thread [Next in Thread>