From: "Darrick J. Wong" djwong@kernel.org
commit 1aecf3734a95f3c167d1495550ca57556d33f7ec upstream.
While refactoring the quota code to create a function to allocate inode change transactions, I noticed that xfs_qm_vop_chown_reserve does more than just make reservations: it also *modifies* the incore counts directly to handle the owner id change for the delalloc blocks.
I then observed that the fssetxattr code continues validating input arguments after making the quota reservation but before dirtying the transaction. If the routine decides to error out, it fails to undo the accounting switch! This leads to incorrect quota reservation and failure down the line.
We can fix this by making the reservation function do only that -- for the new dquot, it reserves ondisk and delalloc blocks to the transaction, and the old dquot hangs on to its incore reservation for now. Once we actually switch the dquots, we can then update the incore reservations because we've dirtied the transaction and it's too late to turn back now.
No fixes tag because this has been broken since the start of git.
Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Brian Foster bfoster@redhat.com Signed-off-by: Amir Goldstein amir73il@gmail.com --- fs/xfs/xfs_qm.c | 92 +++++++++++++++++++------------------------------ 1 file changed, 35 insertions(+), 57 deletions(-)
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c index b2a9abee8b2b..64e5da33733b 100644 --- a/fs/xfs/xfs_qm.c +++ b/fs/xfs/xfs_qm.c @@ -1785,6 +1785,29 @@ xfs_qm_vop_chown( xfs_trans_mod_dquot(tp, newdq, bfield, ip->i_d.di_nblocks); xfs_trans_mod_dquot(tp, newdq, XFS_TRANS_DQ_ICOUNT, 1);
+ /* + * Back when we made quota reservations for the chown, we reserved the + * ondisk blocks + delalloc blocks with the new dquot. Now that we've + * switched the dquots, decrease the new dquot's block reservation + * (having already bumped up the real counter) so that we don't have + * any reservation to give back when we commit. + */ + xfs_trans_mod_dquot(tp, newdq, XFS_TRANS_DQ_RES_BLKS, + -ip->i_delayed_blks); + + /* + * Give the incore reservation for delalloc blocks back to the old + * dquot. We don't normally handle delalloc quota reservations + * transactionally, so just lock the dquot and subtract from the + * reservation. Dirty the transaction because it's too late to turn + * back now. + */ + tp->t_flags |= XFS_TRANS_DIRTY; + xfs_dqlock(prevdq); + ASSERT(prevdq->q_blk.reserved >= ip->i_delayed_blks); + prevdq->q_blk.reserved -= ip->i_delayed_blks; + xfs_dqunlock(prevdq); + /* * Take an extra reference, because the inode is going to keep * this dquot pointer even after the trans_commit. @@ -1807,84 +1830,39 @@ xfs_qm_vop_chown_reserve( uint flags) { struct xfs_mount *mp = ip->i_mount; - uint64_t delblks; unsigned int blkflags; - struct xfs_dquot *udq_unres = NULL; - struct xfs_dquot *gdq_unres = NULL; - struct xfs_dquot *pdq_unres = NULL; struct xfs_dquot *udq_delblks = NULL; struct xfs_dquot *gdq_delblks = NULL; struct xfs_dquot *pdq_delblks = NULL; - int error; -
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)); ASSERT(XFS_IS_QUOTA_RUNNING(mp));
- delblks = ip->i_delayed_blks; blkflags = XFS_IS_REALTIME_INODE(ip) ? XFS_QMOPT_RES_RTBLKS : XFS_QMOPT_RES_REGBLKS;
if (XFS_IS_UQUOTA_ON(mp) && udqp && - i_uid_read(VFS_I(ip)) != udqp->q_id) { + i_uid_read(VFS_I(ip)) != udqp->q_id) udq_delblks = udqp; - /* - * If there are delayed allocation blocks, then we have to - * unreserve those from the old dquot, and add them to the - * new dquot. - */ - if (delblks) { - ASSERT(ip->i_udquot); - udq_unres = ip->i_udquot; - } - } + if (XFS_IS_GQUOTA_ON(ip->i_mount) && gdqp && - i_gid_read(VFS_I(ip)) != gdqp->q_id) { + i_gid_read(VFS_I(ip)) != gdqp->q_id) gdq_delblks = gdqp; - if (delblks) { - ASSERT(ip->i_gdquot); - gdq_unres = ip->i_gdquot; - } - }
if (XFS_IS_PQUOTA_ON(ip->i_mount) && pdqp && - ip->i_d.di_projid != pdqp->q_id) { + ip->i_d.di_projid != pdqp->q_id) pdq_delblks = pdqp; - if (delblks) { - ASSERT(ip->i_pdquot); - pdq_unres = ip->i_pdquot; - } - } - - error = xfs_trans_reserve_quota_bydquots(tp, ip->i_mount, - udq_delblks, gdq_delblks, pdq_delblks, - ip->i_d.di_nblocks, 1, flags | blkflags); - if (error) - return error;
/* - * Do the delayed blks reservations/unreservations now. Since, these - * are done without the help of a transaction, if a reservation fails - * its previous reservations won't be automatically undone by trans - * code. So, we have to do it manually here. + * Reserve enough quota to handle blocks on disk and reserved for a + * delayed allocation. We'll actually transfer the delalloc + * reservation between dquots at chown time, even though that part is + * only semi-transactional. */ - if (delblks) { - /* - * Do the reservations first. Unreservation can't fail. - */ - ASSERT(udq_delblks || gdq_delblks || pdq_delblks); - ASSERT(udq_unres || gdq_unres || pdq_unres); - error = xfs_trans_reserve_quota_bydquots(NULL, ip->i_mount, - udq_delblks, gdq_delblks, pdq_delblks, - (xfs_qcnt_t)delblks, 0, flags | blkflags); - if (error) - return error; - xfs_trans_reserve_quota_bydquots(NULL, ip->i_mount, - udq_unres, gdq_unres, pdq_unres, - -((xfs_qcnt_t)delblks), 0, blkflags); - } - - return 0; + return xfs_trans_reserve_quota_bydquots(tp, ip->i_mount, udq_delblks, + gdq_delblks, pdq_delblks, + ip->i_d.di_nblocks + ip->i_delayed_blks, + 1, blkflags | flags); }
int