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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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79
fs/xfs/xfs_file.c
View File

@@ -47,40 +47,6 @@
static const struct vm_operations_struct xfs_file_vm_ops;
/*
* Locking primitives for read and write IO paths to ensure we consistently use
* and order the inode->i_mutex, ip->i_lock and ip->i_iolock.
*/
static inline void
xfs_rw_ilock(
struct xfs_inode *ip,
int type)
{
if (type & XFS_IOLOCK_EXCL)
inode_lock(VFS_I(ip));
xfs_ilock(ip, type);
}
static inline void
xfs_rw_iunlock(
struct xfs_inode *ip,
int type)
{
xfs_iunlock(ip, type);
if (type & XFS_IOLOCK_EXCL)
inode_unlock(VFS_I(ip));
}
static inline void
xfs_rw_ilock_demote(
struct xfs_inode *ip,
int type)
{
xfs_ilock_demote(ip, type);
if (type & XFS_IOLOCK_EXCL)
inode_unlock(VFS_I(ip));
}
/*
* Clear the specified ranges to zero through either the pagecache or DAX.
* Holes and unwritten extents will be left as-is as they already are zeroed.
@@ -273,7 +239,7 @@ xfs_file_dio_aio_read(
file_accessed(iocb->ki_filp);
xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
xfs_ilock(ip, XFS_IOLOCK_SHARED);
if (mapping->nrpages) {
ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, end);
if (ret)
@@ -299,7 +265,7 @@ xfs_file_dio_aio_read(
}
out_unlock:
xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
}
@@ -317,9 +283,9 @@ xfs_file_dax_read(
if (!count)
return 0; /* skip atime */
xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
xfs_ilock(ip, XFS_IOLOCK_SHARED);
ret = dax_iomap_rw(iocb, to, &xfs_iomap_ops);
xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
file_accessed(iocb->ki_filp);
return ret;
@@ -335,9 +301,9 @@ xfs_file_buffered_aio_read(
trace_xfs_file_buffered_read(ip, iov_iter_count(to), iocb->ki_pos);
xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
xfs_ilock(ip, XFS_IOLOCK_SHARED);
ret = generic_file_read_iter(iocb, to);
xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
}
@@ -418,15 +384,18 @@ restart:
if (error <= 0)
return error;
error = xfs_break_layouts(inode, iolock, true);
error = xfs_break_layouts(inode, iolock);
if (error)
return error;
/* For changing security info in file_remove_privs() we need i_mutex */
/*
* For changing security info in file_remove_privs() we need i_rwsem
* exclusively.
*/
if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) {
xfs_rw_iunlock(ip, *iolock);
xfs_iunlock(ip, *iolock);
*iolock = XFS_IOLOCK_EXCL;
xfs_rw_ilock(ip, *iolock);
xfs_ilock(ip, *iolock);
goto restart;
}
/*
@@ -451,9 +420,9 @@ restart:
spin_unlock(&ip->i_flags_lock);
if (!drained_dio) {
if (*iolock == XFS_IOLOCK_SHARED) {
xfs_rw_iunlock(ip, *iolock);
xfs_iunlock(ip, *iolock);
*iolock = XFS_IOLOCK_EXCL;
xfs_rw_ilock(ip, *iolock);
xfs_ilock(ip, *iolock);
iov_iter_reexpand(from, count);
}
/*
@@ -559,7 +528,7 @@ xfs_file_dio_aio_write(
iolock = XFS_IOLOCK_SHARED;
}
xfs_rw_ilock(ip, iolock);
xfs_ilock(ip, iolock);
ret = xfs_file_aio_write_checks(iocb, from, &iolock);
if (ret)
@@ -591,7 +560,7 @@ xfs_file_dio_aio_write(
if (unaligned_io)
inode_dio_wait(inode);
else if (iolock == XFS_IOLOCK_EXCL) {
xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
iolock = XFS_IOLOCK_SHARED;
}
@@ -621,7 +590,7 @@ xfs_file_dio_aio_write(
iov_iter_advance(from, ret);
}
out:
xfs_rw_iunlock(ip, iolock);
xfs_iunlock(ip, iolock);
/*
* No fallback to buffered IO on errors for XFS, direct IO will either
@@ -643,7 +612,7 @@ xfs_file_dax_write(
size_t count;
loff_t pos;
xfs_rw_ilock(ip, iolock);
xfs_ilock(ip, iolock);
ret = xfs_file_aio_write_checks(iocb, from, &iolock);
if (ret)
goto out;
@@ -652,15 +621,13 @@ xfs_file_dax_write(
count = iov_iter_count(from);
trace_xfs_file_dax_write(ip, count, pos);
ret = dax_iomap_rw(iocb, from, &xfs_iomap_ops);
if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
i_size_write(inode, iocb->ki_pos);
error = xfs_setfilesize(ip, pos, ret);
}
out:
xfs_rw_iunlock(ip, iolock);
xfs_iunlock(ip, iolock);
return error ? error : ret;
}
@@ -677,7 +644,7 @@ xfs_file_buffered_aio_write(
int enospc = 0;
int iolock = XFS_IOLOCK_EXCL;
xfs_rw_ilock(ip, iolock);
xfs_ilock(ip, iolock);
ret = xfs_file_aio_write_checks(iocb, from, &iolock);
if (ret)
@@ -721,7 +688,7 @@ write_retry:
current->backing_dev_info = NULL;
out:
xfs_rw_iunlock(ip, iolock);
xfs_iunlock(ip, iolock);
return ret;
}
@@ -797,7 +764,7 @@ xfs_file_fallocate(
return -EOPNOTSUPP;
xfs_ilock(ip, iolock);
error = xfs_break_layouts(inode, &iolock, false);
error = xfs_break_layouts(inode, &iolock);
if (error)
goto out_unlock;