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xfs: remove i_iolock and use i_rwsem in the VFS inode instead

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This patch drops the XFS-own i_iolock and uses the VFS i_rwsem which
recently replaced i_mutex instead.  This means we only have to take
one lock instead of two in many fast path operations, and we can
also shrink the xfs_inode structure.  Thanks to the xfs_ilock family
there is very little churn, the only thing of note is that we need
to switch to use the lock_two_directory helper for taking the i_rwsem
on two inodes in a few places to make sure our lock order matches
the one used in the VFS.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Christoph Hellwig
2016-11-30 14:33:25 +11:00
committed by Dave Chinner
parent f8319483f5
commit 6552321831
14 changed files with 86 additions and 159 deletions
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14
fs/xfs/xfs_reflink.c
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@ -1251,13 +1251,11 @@ xfs_reflink_remap_range(
return -EIO;
/* Lock both files against IO */
if (same_inode) {
xfs_ilock(src, XFS_IOLOCK_EXCL);
lock_two_nondirectories(inode_in, inode_out);
if (same_inode)
xfs_ilock(src, XFS_MMAPLOCK_EXCL);
} else {
xfs_lock_two_inodes(src, dest, XFS_IOLOCK_EXCL);
else
xfs_lock_two_inodes(src, dest, XFS_MMAPLOCK_EXCL);
}
/* Don't touch certain kinds of inodes */
ret = -EPERM;
@ -1402,11 +1400,9 @@ xfs_reflink_remap_range(
out_unlock:
xfs_iunlock(src, XFS_MMAPLOCK_EXCL);
xfs_iunlock(src, XFS_IOLOCK_EXCL);
if (src->i_ino != dest->i_ino) {
if (!same_inode)
xfs_iunlock(dest, XFS_MMAPLOCK_EXCL);
xfs_iunlock(dest, XFS_IOLOCK_EXCL);
}
unlock_two_nondirectories(inode_in, inode_out);
if (ret)
trace_xfs_reflink_remap_range_error(dest, ret, _RET_IP_);
return ret;