[RFC PATCH 2/4] xfs: add xfs_create_tmpfile() for O_TMPFILE support
Dave Chinner
david at fromorbit.com
Mon Nov 25 15:36:01 CST 2013
On Mon, Nov 25, 2013 at 07:32:32PM +0800, Zhi Yong Wu wrote:
> From: Zhi Yong Wu <wuzhy at linux.vnet.ibm.com>
>
> The function is used to create one O_TMPFILE file.
>
> http://oss.sgi.com/archives/xfs/2013-08/msg00339.html
>
> Signed-off-by: Zhi Yong Wu <wuzhy at linux.vnet.ibm.com>
> ---
> fs/xfs/xfs_inode.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++
> fs/xfs/xfs_inode.h | 2 +
> fs/xfs/xfs_shared.h | 4 +-
> fs/xfs/xfs_trans_resv.c | 35 ++++++++++++
> fs/xfs/xfs_trans_resv.h | 2 +
> fs/xfs/xfs_trans_space.h | 2 +
> 6 files changed, 173 insertions(+), 1 deletions(-)
>
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 1c23bdf..e1832de 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1337,6 +1337,135 @@ xfs_create(
> }
>
> int
> +xfs_create_tmpfile(
> + xfs_mount_t *mp,
> + umode_t mode,
> + dev_t rdev,
> + xfs_inode_t **ipp)
> +{
> + struct xfs_inode *ip = NULL;
> + struct xfs_trans *tp = NULL;
> + int error;
> + uint cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
> + struct xfs_dquot *udqp = NULL;
> + struct xfs_dquot *gdqp = NULL;
> + struct xfs_dquot *pdqp = NULL;
> + struct xfs_trans_res *tres;
> + uint resblks;
> +
> + if (XFS_FORCED_SHUTDOWN(mp))
> + return XFS_ERROR(EIO);
> +
> + /*
> + * Make sure that we have allocated dquot(s) on disk.
> + */
> + error = xfs_qm_vop_dqalloc(NULL, mp, xfs_kuid_to_uid(current_fsuid()),
> + xfs_kgid_to_gid(current_fsgid()),
> + XFS_PROJID_DEFAULT,
> + XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
> + &udqp, &gdqp, &pdqp);
> + if (error)
> + return error;
Is XFS_PROJID_DEFAULT correct here? If we are getting a parent inode
from ->tmpfile, then this should be handled the same way as for
xfs_create.
> +
> + resblks = XFS_CREATE_TMPFILE_SPACE_RES(mp);
> + tp = xfs_trans_alloc(mp, XFS_TRANS_CREATE_TMPFILE);
> +
> + /*
> + * Initially assume that the file does not exist and
> + * reserve the resources for that case. If that is not
> + * the case we'll drop the one we have and get a more
> + * appropriate transaction later.
> + */
> + tres = &M_RES(mp)->tr_create_tmpfile;
> + error = xfs_trans_reserve(tp, tres, resblks, 0);
> + if (error == ENOSPC) {
> + /* flush outstanding delalloc blocks and retry */
> + xfs_flush_inodes(mp);
> + error = xfs_trans_reserve(tp, tres, resblks, 0);
> + }
> + if (error == ENOSPC) {
> + /* No space at all so try a "no-allocation" reservation */
> + resblks = 0;
> + error = xfs_trans_reserve(tp, tres, 0, 0);
> + }
> + if (error) {
> + cancel_flags = 0;
> + goto out_trans_cancel;
> + }
I don't think this is necessary here. The ENOSPC flushing in
xfs_create() is done to ensure we have space for directory block
creation, not so much for inode allocation. Hence it doesn't make a
lot of sense to have this here....
> + /*
> + * Reserve disk quota and the inode.
> + */
> + error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
> + pdqp, resblks, 1, 0);
> + if (error)
> + goto out_trans_cancel;
> +
> + /*
> + * A newly created regular or special file just has one directory
> + * entry pointing to them, but a directory also the "." entry
> + * pointing to itself.
> + */
> + error = xfs_dir_ialloc(&tp, NULL, mode, 1, rdev,
> + XFS_PROJID_DEFAULT, resblks > 0,
> + &ip, NULL);
> + if (error) {
> + if (error == ENOSPC)
> + goto out_trans_cancel;
> + goto out_trans_abort;
> + }
> +
> + /*
> + * If this is a synchronous mount, make sure that the
> + * create transaction goes to disk before returning to
> + * the user.
> + */
> + if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC))
> + xfs_trans_set_sync(tp);
I'm not sure that XFS_MOUNT_DIRSYNC shoul dbe checked here, as there
is no directory operations to synchronise at all...
> +STATIC uint
> +xfs_calc_icreate_tmpfile_reservation(xfs_mount_t *mp)
> +{
> + return XFS_DQUOT_LOGRES(mp) +
> + xfs_calc_icreate_resv_alloc(mp) +
> + xfs_calc_inode_res(mp, 1) +
> + xfs_calc_buf_res(1, XFS_FSB_TO_B(mp, 1)) +
> + xfs_calc_buf_res(2, mp->m_sb.sb_sectsize);
> +}
> +
> +STATIC uint
> +__xfs_calc_create_tmpfile_reservation(
> + struct xfs_mount *mp)
> +{
> + return XFS_DQUOT_LOGRES(mp) +
> + xfs_calc_create_resv_alloc(mp) +
> + xfs_calc_inode_res(mp, 1) +
> + xfs_calc_buf_res(1, XFS_FSB_TO_B(mp, 1)) +
> + xfs_calc_buf_res(2, mp->m_sb.sb_sectsize);
> +}
What exactly is being modified here? All of the other reservations
have comments explaining what each of the individual components of
the reservation are. Yes, I can see that there's an inode, a
filesystem block and 2 sectors being reserved, but what are they?
It's also double counting the XFS_DQUOT_LOGRES(), as they are
accounted for in xfs_calc_[i]create_reservation().
Also, the directory create reservations are broken up into two
components - the inode allocation and the common directory name
creation component, and so the tmpfile reservation should probably
be broken up the same way. i.e this:
> +
> +STATIC uint
> +xfs_calc_create_tmpfile_reservation(
> + struct xfs_mount *mp)
> +{
> + if (xfs_sb_version_hascrc(&mp->m_sb))
> + return xfs_calc_icreate_tmpfile_reservation(mp);
> + return __xfs_calc_create_tmpfile_reservation(mp);
> +}
Could simply be:
STATIC uint
xfs_calc_create_tmpfile_reservation(
struct xfs_mount *mp)
{
uint res;
if (xfs_sb_version_hascrc(&mp->m_sb))
res = xfs_calc_icreate_resv_alloc(mp);
else
res = xfs_calc_create_resv_alloc(mp);
return res + xfs_calc_iunlink_add_resv(mp);
}
> diff --git a/fs/xfs/xfs_trans_space.h b/fs/xfs/xfs_trans_space.h
> index 7d2c920..16fba89 100644
> --- a/fs/xfs/xfs_trans_space.h
> +++ b/fs/xfs/xfs_trans_space.h
> @@ -61,6 +61,8 @@
> (XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK) + XFS_B_TO_FSB(mp, v))
> #define XFS_CREATE_SPACE_RES(mp,nl) \
> (XFS_IALLOC_SPACE_RES(mp) + XFS_DIRENTER_SPACE_RES(mp,nl))
> +#define XFS_CREATE_TMPFILE_SPACE_RES(mp) \
> + XFS_IALLOC_SPACE_RES(mp)
I wouldn't bother with this macro - just use XFS_IALLOC_SPACE_RES()
directly.
Cheers,
Dave.
--
Dave Chinner
david at fromorbit.com
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