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xfs: sanitise error handling in xfs_alloc_fix_freelist

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The error handling is currently an inconsistent mess as every error
condition handles return values and releasing buffers individually.
Clean this up by using gotos and a sane error label stack.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Dave Chinner 2015-06-22 10:13:19 +10:00 committed by Dave Chinner
parent 72d552854b
commit 396503fc83
1 changed files with 55 additions and 56 deletions
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111
fs/xfs/libxfs/xfs_alloc.c
View file

@ -1877,84 +1877,77 @@ xfs_alloc_space_available(
*/
STATIC int /* error */
xfs_alloc_fix_freelist(
xfs_alloc_arg_t *args, /* allocation argument structure */
int flags) /* XFS_ALLOC_FLAG_... */
struct xfs_alloc_arg *args, /* allocation argument structure */
int flags) /* XFS_ALLOC_FLAG_... */
{
xfs_buf_t *agbp; /* agf buffer pointer */
xfs_buf_t *agflbp;/* agfl buffer pointer */
xfs_agblock_t bno; /* freelist block */
int error; /* error result code */
xfs_mount_t *mp; /* file system mount point structure */
xfs_extlen_t need; /* total blocks needed in freelist */
xfs_perag_t *pag; /* per-ag information structure */
xfs_alloc_arg_t targs; /* local allocation arguments */
xfs_trans_t *tp; /* transaction pointer */
struct xfs_mount *mp = args->mp;
struct xfs_perag *pag = args->pag;
struct xfs_trans *tp = args->tp;
struct xfs_buf *agbp = NULL;
struct xfs_buf *agflbp = NULL;
struct xfs_alloc_arg targs; /* local allocation arguments */
xfs_agblock_t bno; /* freelist block */
xfs_extlen_t need; /* total blocks needed in freelist */
int error;
mp = args->mp;
pag = args->pag;
tp = args->tp;
if (!pag->pagf_init) {
if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags,
&agbp)))
return error;
error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
if (error)
goto out_no_agbp;
if (!pag->pagf_init) {
ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
args->agbp = NULL;
return 0;
goto out_agbp_relse;
}
} else
agbp = NULL;
}
/*
* If this is a metadata preferred pag and we are user data
* then try somewhere else if we are not being asked to
* try harder at this point
* If this is a metadata preferred pag and we are user data then try
* somewhere else if we are not being asked to try harder at this
* point
*/
if (pag->pagf_metadata && args->userdata &&
(flags & XFS_ALLOC_FLAG_TRYLOCK)) {
ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
args->agbp = NULL;
return 0;
goto out_agbp_relse;
}
need = XFS_MIN_FREELIST_PAG(pag, mp);
if (!xfs_alloc_space_available(args, need, flags)) {
if (agbp)
xfs_trans_brelse(tp, agbp);
args->agbp = NULL;
return 0;
}
if (!xfs_alloc_space_available(args, need, flags))
goto out_agbp_relse;
/*
* Get the a.g. freespace buffer.
* Can fail if we're not blocking on locks, and it's held.
*/
if (agbp == NULL) {
if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags,
&agbp)))
return error;
if (agbp == NULL) {
if (!agbp) {
error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
if (error)
goto out_no_agbp;
if (!agbp) {
ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
args->agbp = NULL;
return 0;
goto out_no_agbp;
}
}
/* If there isn't enough total space or single-extent, reject it. */
need = XFS_MIN_FREELIST_PAG(pag, mp);
if (!xfs_alloc_space_available(args, need, flags)) {
xfs_trans_brelse(tp, agbp);
args->agbp = NULL;
return 0;
}
if (!xfs_alloc_space_available(args, need, flags))
goto out_agbp_relse;
/*
* Make the freelist shorter if it's too long.
*
* Note that from this point onwards, we will always release the agf and
* agfl buffers on error. This handles the case where we error out and
* the buffers are clean or may not have been joined to the transaction
* and hence need to be released manually. If they have been joined to
* the transaction, then xfs_trans_brelse() will handle them
* appropriately based on the recursion count and dirty state of the
* buffer.
*
* XXX (dgc): When we have lots of free space, does this buy us
* anything other than extra overhead when we need to put more blocks
* back on the free list? Maybe we should only do this when space is
@ -1965,10 +1958,10 @@ xfs_alloc_fix_freelist(
error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
if (error)
return error;
goto out_agbp_relse;
error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1);
if (error)
return error;
goto out_agbp_relse;
bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
xfs_trans_binval(tp, bp);
}
@ -1983,7 +1976,7 @@ xfs_alloc_fix_freelist(
targs.pag = pag;
error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp);
if (error)
return error;
goto out_agbp_relse;
/* Make the freelist longer if it's too short. */
while (pag->pagf_flcount < need) {
@ -1992,10 +1985,9 @@ xfs_alloc_fix_freelist(
/* Allocate as many blocks as possible at once. */
error = xfs_alloc_ag_vextent(&targs);
if (error) {
xfs_trans_brelse(tp, agflbp);
return error;
}
if (error)
goto out_agflbp_relse;
/*
* Stop if we run out. Won't happen if callers are obeying
* the restrictions correctly. Can happen for free calls
@ -2004,9 +1996,7 @@ xfs_alloc_fix_freelist(
if (targs.agbno == NULLAGBLOCK) {
if (flags & XFS_ALLOC_FLAG_FREEING)
break;
xfs_trans_brelse(tp, agflbp);
args->agbp = NULL;
return 0;
goto out_agflbp_relse;
}
/*
* Put each allocated block on the list.
@ -2015,12 +2005,21 @@ xfs_alloc_fix_freelist(
error = xfs_alloc_put_freelist(tp, agbp,
agflbp, bno, 0);
if (error)
return error;
goto out_agflbp_relse;
}
}
xfs_trans_brelse(tp, agflbp);
args->agbp = agbp;
return 0;
out_agflbp_relse:
xfs_trans_brelse(tp, agflbp);
out_agbp_relse:
if (agbp)
xfs_trans_brelse(tp, agbp);
out_no_agbp:
args->agbp = NULL;
return error;
}
/*