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xfs: refactor swapext code
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Refactor the swapext function to pull out the fork swapping piece
into a separate function.  In the next patch we'll add in the bit
we need to make it work with rmap filesystems.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Darrick J. Wong committed Oct 5, 2016
1 parent e06259a commit 39aff5f
Showing 1 changed file with 144 additions and 131 deletions.
275 changes: 144 additions & 131 deletions fs/xfs/xfs_bmap_util.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1649,127 +1649,37 @@ xfs_swap_extent_flush(
return 0;
}

int
xfs_swap_extents(
struct xfs_inode *ip, /* target inode */
struct xfs_inode *tip, /* tmp inode */
struct xfs_swapext *sxp)
/* Swap the extents of two files by swapping data forks. */
STATIC int
xfs_swap_extent_forks(
struct xfs_trans *tp,
struct xfs_inode *ip,
struct xfs_inode *tip,
int *src_log_flags,
int *target_log_flags)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
struct xfs_bstat *sbp = &sxp->sx_stat;
struct xfs_ifork *tempifp, *ifp, *tifp;
int src_log_flags, target_log_flags;
int error = 0;
struct xfs_ifork tempifp, *ifp, *tifp;
int aforkblks = 0;
int taforkblks = 0;
__uint64_t tmp;
int lock_flags;
struct xfs_ifork *cowfp;
__uint64_t f;

/* XXX: we can't do this with rmap, will fix later */
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
return -EOPNOTSUPP;

tempifp = kmem_alloc(sizeof(xfs_ifork_t), KM_MAYFAIL);
if (!tempifp) {
error = -ENOMEM;
goto out;
}

/*
* Lock the inodes against other IO, page faults and truncate to
* begin with. Then we can ensure the inodes are flushed and have no
* page cache safely. Once we have done this we can take the ilocks and
* do the rest of the checks.
*/
lock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
xfs_lock_two_inodes(ip, tip, XFS_IOLOCK_EXCL);
xfs_lock_two_inodes(ip, tip, XFS_MMAPLOCK_EXCL);

/* Verify that both files have the same format */
if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
error = -EINVAL;
goto out_unlock;
}

/* Verify both files are either real-time or non-realtime */
if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
error = -EINVAL;
goto out_unlock;
}

error = xfs_swap_extent_flush(ip);
if (error)
goto out_unlock;
error = xfs_swap_extent_flush(tip);
if (error)
goto out_unlock;

error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
if (error)
goto out_unlock;

/*
* Lock and join the inodes to the tansaction so that transaction commit
* or cancel will unlock the inodes from this point onwards.
*/
xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
lock_flags |= XFS_ILOCK_EXCL;
xfs_trans_ijoin(tp, ip, lock_flags);
xfs_trans_ijoin(tp, tip, lock_flags);


/* Verify all data are being swapped */
if (sxp->sx_offset != 0 ||
sxp->sx_length != ip->i_d.di_size ||
sxp->sx_length != tip->i_d.di_size) {
error = -EFAULT;
goto out_trans_cancel;
}

trace_xfs_swap_extent_before(ip, 0);
trace_xfs_swap_extent_before(tip, 1);

/* check inode formats now that data is flushed */
error = xfs_swap_extents_check_format(ip, tip);
if (error) {
xfs_notice(mp,
"%s: inode 0x%llx format is incompatible for exchanging.",
__func__, ip->i_ino);
goto out_trans_cancel;
}
int error;

/*
* Compare the current change & modify times with that
* passed in. If they differ, we abort this swap.
* This is the mechanism used to ensure the calling
* process that the file was not changed out from
* under it.
*/
if ((sbp->bs_ctime.tv_sec != VFS_I(ip)->i_ctime.tv_sec) ||
(sbp->bs_ctime.tv_nsec != VFS_I(ip)->i_ctime.tv_nsec) ||
(sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
(sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
error = -EBUSY;
goto out_trans_cancel;
}
/*
* Count the number of extended attribute blocks
*/
if ( ((XFS_IFORK_Q(ip) != 0) && (ip->i_d.di_anextents > 0)) &&
(ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &aforkblks);
error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK,
&aforkblks);
if (error)
goto out_trans_cancel;
return error;
}
if ( ((XFS_IFORK_Q(tip) != 0) && (tip->i_d.di_anextents > 0)) &&
(tip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK,
&taforkblks);
&taforkblks);
if (error)
goto out_trans_cancel;
return error;
}

/*
Expand All @@ -1778,41 +1688,33 @@ xfs_swap_extents(
* buffers, and so the validation done on read will expect the owner
* field to be correctly set. Once we change the owners, we can swap the
* inode forks.
*
* Note the trickiness in setting the log flags - we set the owner log
* flag on the opposite inode (i.e. the inode we are setting the new
* owner to be) because once we swap the forks and log that, log
* recovery is going to see the fork as owned by the swapped inode,
* not the pre-swapped inodes.
*/
src_log_flags = XFS_ILOG_CORE;
target_log_flags = XFS_ILOG_CORE;
if (ip->i_d.di_version == 3 &&
ip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
target_log_flags |= XFS_ILOG_DOWNER;
(*target_log_flags) |= XFS_ILOG_DOWNER;
error = xfs_bmbt_change_owner(tp, ip, XFS_DATA_FORK,
tip->i_ino, NULL);
if (error)
goto out_trans_cancel;
return error;
}

if (tip->i_d.di_version == 3 &&
tip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
src_log_flags |= XFS_ILOG_DOWNER;
(*src_log_flags) |= XFS_ILOG_DOWNER;
error = xfs_bmbt_change_owner(tp, tip, XFS_DATA_FORK,
ip->i_ino, NULL);
if (error)
goto out_trans_cancel;
return error;
}

/*
* Swap the data forks of the inodes
*/
ifp = &ip->i_df;
tifp = &tip->i_df;
*tempifp = *ifp; /* struct copy */
tempifp = *ifp; /* struct copy */
*ifp = *tifp; /* struct copy */
*tifp = *tempifp; /* struct copy */
*tifp = tempifp; /* struct copy */

/*
* Fix the on-disk inode values
Expand Down Expand Up @@ -1852,12 +1754,12 @@ xfs_swap_extents(
ifp->if_u1.if_extents =
ifp->if_u2.if_inline_ext;
}
src_log_flags |= XFS_ILOG_DEXT;
(*src_log_flags) |= XFS_ILOG_DEXT;
break;
case XFS_DINODE_FMT_BTREE:
ASSERT(ip->i_d.di_version < 3 ||
(src_log_flags & XFS_ILOG_DOWNER));
src_log_flags |= XFS_ILOG_DBROOT;
(*src_log_flags & XFS_ILOG_DOWNER));
(*src_log_flags) |= XFS_ILOG_DBROOT;
break;
}

Expand All @@ -1871,15 +1773,126 @@ xfs_swap_extents(
tifp->if_u1.if_extents =
tifp->if_u2.if_inline_ext;
}
target_log_flags |= XFS_ILOG_DEXT;
(*target_log_flags) |= XFS_ILOG_DEXT;
break;
case XFS_DINODE_FMT_BTREE:
target_log_flags |= XFS_ILOG_DBROOT;
(*target_log_flags) |= XFS_ILOG_DBROOT;
ASSERT(tip->i_d.di_version < 3 ||
(target_log_flags & XFS_ILOG_DOWNER));
(*target_log_flags & XFS_ILOG_DOWNER));
break;
}

return 0;
}

int
xfs_swap_extents(
struct xfs_inode *ip, /* target inode */
struct xfs_inode *tip, /* tmp inode */
struct xfs_swapext *sxp)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
struct xfs_bstat *sbp = &sxp->sx_stat;
int src_log_flags, target_log_flags;
int error = 0;
int lock_flags;
struct xfs_ifork *cowfp;
__uint64_t f;

/*
* Lock the inodes against other IO, page faults and truncate to
* begin with. Then we can ensure the inodes are flushed and have no
* page cache safely. Once we have done this we can take the ilocks and
* do the rest of the checks.
*/
lock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
xfs_lock_two_inodes(ip, tip, XFS_IOLOCK_EXCL);
xfs_lock_two_inodes(ip, tip, XFS_MMAPLOCK_EXCL);

/* Verify that both files have the same format */
if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
error = -EINVAL;
goto out_unlock;
}

/* Verify both files are either real-time or non-realtime */
if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
error = -EINVAL;
goto out_unlock;
}

error = xfs_swap_extent_flush(ip);
if (error)
goto out_unlock;
error = xfs_swap_extent_flush(tip);
if (error)
goto out_unlock;

error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
if (error)
goto out_unlock;

/*
* Lock and join the inodes to the tansaction so that transaction commit
* or cancel will unlock the inodes from this point onwards.
*/
xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
lock_flags |= XFS_ILOCK_EXCL;
xfs_trans_ijoin(tp, ip, 0);
xfs_trans_ijoin(tp, tip, 0);


/* Verify all data are being swapped */
if (sxp->sx_offset != 0 ||
sxp->sx_length != ip->i_d.di_size ||
sxp->sx_length != tip->i_d.di_size) {
error = -EFAULT;
goto out_trans_cancel;
}

trace_xfs_swap_extent_before(ip, 0);
trace_xfs_swap_extent_before(tip, 1);

/* check inode formats now that data is flushed */
error = xfs_swap_extents_check_format(ip, tip);
if (error) {
xfs_notice(mp,
"%s: inode 0x%llx format is incompatible for exchanging.",
__func__, ip->i_ino);
goto out_trans_cancel;
}

/*
* Compare the current change & modify times with that
* passed in. If they differ, we abort this swap.
* This is the mechanism used to ensure the calling
* process that the file was not changed out from
* under it.
*/
if ((sbp->bs_ctime.tv_sec != VFS_I(ip)->i_ctime.tv_sec) ||
(sbp->bs_ctime.tv_nsec != VFS_I(ip)->i_ctime.tv_nsec) ||
(sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
(sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
error = -EBUSY;
goto out_trans_cancel;
}

/*
* Note the trickiness in setting the log flags - we set the owner log
* flag on the opposite inode (i.e. the inode we are setting the new
* owner to be) because once we swap the forks and log that, log
* recovery is going to see the fork as owned by the swapped inode,
* not the pre-swapped inodes.
*/
src_log_flags = XFS_ILOG_CORE;
target_log_flags = XFS_ILOG_CORE;

error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
&target_log_flags);
if (error)
goto out_trans_cancel;

/* Do we have to swap reflink flags? */
if ((ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK) ^
(tip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK)) {
Expand Down Expand Up @@ -1909,16 +1922,16 @@ xfs_swap_extents(

trace_xfs_swap_extent_after(ip, 0);
trace_xfs_swap_extent_after(tip, 1);
out:
kmem_free(tempifp);
return error;

out_unlock:
xfs_iunlock(ip, lock_flags);
xfs_iunlock(tip, lock_flags);
goto out;
return error;

out_trans_cancel:
xfs_trans_cancel(tp);
goto out;

out_unlock:
xfs_iunlock(ip, lock_flags);
xfs_iunlock(tip, lock_flags);
return error;
}

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