Re: [PATCH V2] xfs: create helper for bmap finish & trans join in attr code

[Eric Sandeen <sandeen@xxxxxxxxxxx>]

On 11/13/15 3:08 AM, Christoph Hellwig wrote:
> On Fri, Nov 13, 2015 at 07:12:31AM +1100, Dave Chinner wrote:
>> On Thu, Nov 12, 2015 at 08:58:01AM -0800, Christoph Hellwig wrote:
>>> I think the problem here is simply that our interfaces suck.
>>> xfs_trans_roll really needs to rejoin any inode to the new transaction
>>> to that was joined to the previous one.  Once we've fixed that we can
>>> get rid of the silly committed arguments and everyone will be happy.
>>
>> xfs_trans_roll is not specifically for rolling transactions with
>> locked inodes in them. We could use it for any object that needs
>> multiple transactions to modify. e.g. we could roll transactions
>> across an AGF (using hold+join) so that it remains locked across
>> multiple allocation/free transactions.
> 
> xfs_trans_roll already logs the inode core, which requires the
> inode to be attached to the transaction.  While I could see the
> point of moving this out of the core __xfs_trans_roll into an
> xfs_trans_roll_inode helper we might as well follow the current
> interface for now.

Trying to follow you guys ;)

Something like this?

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index dbae649..d23bce8 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -91,32 +91,32 @@ xfs_zero_extent(
  * last due to locking considerations.  We never free any extents in
  * the first transaction.
  *
- * Return 1 if the given transaction was committed and a new one
- * started, and 0 otherwise in the committed parameter.
+ * If an inode *ip is provided, rejoin it to the transaction if
+ * the transaction was committed.
  */
 int                                            /* error */
 xfs_bmap_finish(
        struct xfs_trans                **tp,   /* transaction pointer addr */
        struct xfs_bmap_free            *flist, /* i/o: list extents to free */
-       int                             *committed)/* xact committed or not */
+       xfs_inode_t                     *ip)
 {
        struct xfs_efd_log_item         *efd;   /* extent free data */
        struct xfs_efi_log_item         *efi;   /* extent free intention */
        int                             error;  /* error return value */
+       int                             committed;/* xact committed or not */
        struct xfs_bmap_free_item       *free;  /* free extent item */
        struct xfs_bmap_free_item       *next;  /* next item on free list */
 
        ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES);
-       if (flist->xbf_count == 0) {
-               *committed = 0;
+       if (flist->xbf_count == 0)
                return 0;
-       }
+
        efi = xfs_trans_get_efi(*tp, flist->xbf_count);
        for (free = flist->xbf_first; free; free = free->xbfi_next)
                xfs_trans_log_efi_extent(*tp, efi, free->xbfi_startblock,
                        free->xbfi_blockcount);
 
-       error = __xfs_trans_roll(tp, NULL, committed);
+       error = __xfs_trans_roll(tp, ip, &committed);
        if (error) {
                /*
                 * If the transaction was committed, drop the EFD reference
@@ -128,16 +128,13 @@ xfs_bmap_finish(
                 * transaction so we should return committed=1 even though we're
                 * returning an error.
                 */
-               if (*committed) {
+               if (committed) {
                        xfs_efi_release(efi);
                        xfs_force_shutdown((*tp)->t_mountp,
                                (error == -EFSCORRUPTED) ?
                                        SHUTDOWN_CORRUPT_INCORE :
                                        SHUTDOWN_META_IO_ERROR);
-               } else {
-                       *committed = 1;
                }
-
                return error;
        }