summaryrefslogtreecommitdiff
path: root/fs/xfs/xfs_inode.c
diff options
context:
space:
mode:
authorChristoph Hellwig <hch@lst.de>2016-11-30 06:33:25 +0300
committerDave Chinner <david@fromorbit.com>2016-11-30 06:33:25 +0300
commit6552321831dce87ff5c466a55b58d472732caadc (patch)
tree84f3de7b89690c84fd13e2efa7a85d4918d342e3 /fs/xfs/xfs_inode.c
parentf8319483f57f1ca22370f4150bb990aca7728a67 (diff)
downloadlinux-6552321831dce87ff5c466a55b58d472732caadc.tar.xz
xfs: remove i_iolock and use i_rwsem in the VFS inode instead
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>
Diffstat (limited to 'fs/xfs/xfs_inode.c')
-rw-r--r--fs/xfs/xfs_inode.c82
1 files changed, 33 insertions, 49 deletions
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 4e560e6a12c1..e9ab42d8965b 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -142,31 +142,31 @@ xfs_ilock_attr_map_shared(
}
/*
- * The xfs inode contains 3 multi-reader locks: the i_iolock the i_mmap_lock and
- * the i_lock. This routine allows various combinations of the locks to be
- * obtained.
+ * In addition to i_rwsem in the VFS inode, the xfs inode contains 2
+ * multi-reader locks: i_mmap_lock and the i_lock. This routine allows
+ * various combinations of the locks to be obtained.
*
* The 3 locks should always be ordered so that the IO lock is obtained first,
* the mmap lock second and the ilock last in order to prevent deadlock.
*
* Basic locking order:
*
- * i_iolock -> i_mmap_lock -> page_lock -> i_ilock
+ * i_rwsem -> i_mmap_lock -> page_lock -> i_ilock
*
* mmap_sem locking order:
*
- * i_iolock -> page lock -> mmap_sem
+ * i_rwsem -> page lock -> mmap_sem
* mmap_sem -> i_mmap_lock -> page_lock
*
* The difference in mmap_sem locking order mean that we cannot hold the
* i_mmap_lock over syscall based read(2)/write(2) based IO. These IO paths can
* fault in pages during copy in/out (for buffered IO) or require the mmap_sem
* in get_user_pages() to map the user pages into the kernel address space for
- * direct IO. Similarly the i_iolock cannot be taken inside a page fault because
+ * direct IO. Similarly the i_rwsem cannot be taken inside a page fault because
* page faults already hold the mmap_sem.
*
* Hence to serialise fully against both syscall and mmap based IO, we need to
- * take both the i_iolock and the i_mmap_lock. These locks should *only* be both
+ * take both the i_rwsem and the i_mmap_lock. These locks should *only* be both
* taken in places where we need to invalidate the page cache in a race
* free manner (e.g. truncate, hole punch and other extent manipulation
* functions).
@@ -191,10 +191,13 @@ xfs_ilock(
(XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0);
- if (lock_flags & XFS_IOLOCK_EXCL)
- mrupdate_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));
- else if (lock_flags & XFS_IOLOCK_SHARED)
- mraccess_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));
+ if (lock_flags & XFS_IOLOCK_EXCL) {
+ down_write_nested(&VFS_I(ip)->i_rwsem,
+ XFS_IOLOCK_DEP(lock_flags));
+ } else if (lock_flags & XFS_IOLOCK_SHARED) {
+ down_read_nested(&VFS_I(ip)->i_rwsem,
+ XFS_IOLOCK_DEP(lock_flags));
+ }
if (lock_flags & XFS_MMAPLOCK_EXCL)
mrupdate_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
@@ -240,10 +243,10 @@ xfs_ilock_nowait(
ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0);
if (lock_flags & XFS_IOLOCK_EXCL) {
- if (!mrtryupdate(&ip->i_iolock))
+ if (!down_write_trylock(&VFS_I(ip)->i_rwsem))
goto out;
} else if (lock_flags & XFS_IOLOCK_SHARED) {
- if (!mrtryaccess(&ip->i_iolock))
+ if (!down_read_trylock(&VFS_I(ip)->i_rwsem))
goto out;
}
@@ -271,9 +274,9 @@ out_undo_mmaplock:
mrunlock_shared(&ip->i_mmaplock);
out_undo_iolock:
if (lock_flags & XFS_IOLOCK_EXCL)
- mrunlock_excl(&ip->i_iolock);
+ up_write(&VFS_I(ip)->i_rwsem);
else if (lock_flags & XFS_IOLOCK_SHARED)
- mrunlock_shared(&ip->i_iolock);
+ up_read(&VFS_I(ip)->i_rwsem);
out:
return 0;
}
@@ -310,9 +313,9 @@ xfs_iunlock(
ASSERT(lock_flags != 0);
if (lock_flags & XFS_IOLOCK_EXCL)
- mrunlock_excl(&ip->i_iolock);
+ up_write(&VFS_I(ip)->i_rwsem);
else if (lock_flags & XFS_IOLOCK_SHARED)
- mrunlock_shared(&ip->i_iolock);
+ up_read(&VFS_I(ip)->i_rwsem);
if (lock_flags & XFS_MMAPLOCK_EXCL)
mrunlock_excl(&ip->i_mmaplock);
@@ -345,7 +348,7 @@ xfs_ilock_demote(
if (lock_flags & XFS_MMAPLOCK_EXCL)
mrdemote(&ip->i_mmaplock);
if (lock_flags & XFS_IOLOCK_EXCL)
- mrdemote(&ip->i_iolock);
+ downgrade_write(&VFS_I(ip)->i_rwsem);
trace_xfs_ilock_demote(ip, lock_flags, _RET_IP_);
}
@@ -370,8 +373,9 @@ xfs_isilocked(
if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
if (!(lock_flags & XFS_IOLOCK_SHARED))
- return !!ip->i_iolock.mr_writer;
- return rwsem_is_locked(&ip->i_iolock.mr_lock);
+ return !debug_locks ||
+ lockdep_is_held_type(&VFS_I(ip)->i_rwsem, 0);
+ return rwsem_is_locked(&VFS_I(ip)->i_rwsem);
}
ASSERT(0);
@@ -421,11 +425,7 @@ xfs_lock_inumorder(int lock_mode, int subclass)
if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)) {
ASSERT(subclass <= XFS_IOLOCK_MAX_SUBCLASS);
- ASSERT(xfs_lockdep_subclass_ok(subclass +
- XFS_IOLOCK_PARENT_VAL));
class += subclass << XFS_IOLOCK_SHIFT;
- if (lock_mode & XFS_IOLOCK_PARENT)
- class += XFS_IOLOCK_PARENT_VAL << XFS_IOLOCK_SHIFT;
}
if (lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) {
@@ -477,8 +477,6 @@ xfs_lock_inodes(
XFS_ILOCK_EXCL));
ASSERT(!(lock_mode & (XFS_IOLOCK_SHARED | XFS_MMAPLOCK_SHARED |
XFS_ILOCK_SHARED)));
- ASSERT(!(lock_mode & XFS_IOLOCK_EXCL) ||
- inodes <= XFS_IOLOCK_MAX_SUBCLASS + 1);
ASSERT(!(lock_mode & XFS_MMAPLOCK_EXCL) ||
inodes <= XFS_MMAPLOCK_MAX_SUBCLASS + 1);
ASSERT(!(lock_mode & XFS_ILOCK_EXCL) ||
@@ -581,10 +579,8 @@ xfs_lock_two_inodes(
int attempts = 0;
xfs_log_item_t *lp;
- if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)) {
- ASSERT(!(lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)));
- ASSERT(!(lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
- } else if (lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL))
+ ASSERT(!(lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));
+ if (lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL))
ASSERT(!(lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
ASSERT(ip0->i_ino != ip1->i_ino);
@@ -715,7 +711,6 @@ xfs_lookup(
if (XFS_FORCED_SHUTDOWN(dp->i_mount))
return -EIO;
- xfs_ilock(dp, XFS_IOLOCK_SHARED);
error = xfs_dir_lookup(NULL, dp, name, &inum, ci_name);
if (error)
goto out_unlock;
@@ -724,14 +719,12 @@ xfs_lookup(
if (error)
goto out_free_name;
- xfs_iunlock(dp, XFS_IOLOCK_SHARED);
return 0;
out_free_name:
if (ci_name)
kmem_free(ci_name->name);
out_unlock:
- xfs_iunlock(dp, XFS_IOLOCK_SHARED);
*ipp = NULL;
return error;
}
@@ -1215,8 +1208,7 @@ xfs_create(
if (error)
goto out_release_inode;
- xfs_ilock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL |
- XFS_IOLOCK_PARENT | XFS_ILOCK_PARENT);
+ xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
unlock_dp_on_error = true;
xfs_defer_init(&dfops, &first_block);
@@ -1252,7 +1244,7 @@ xfs_create(
* the transaction cancel unlocking dp so don't do it explicitly in the
* error path.
*/
- xfs_trans_ijoin(tp, dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
unlock_dp_on_error = false;
error = xfs_dir_createname(tp, dp, name, ip->i_ino,
@@ -1325,7 +1317,7 @@ xfs_create(
xfs_qm_dqrele(pdqp);
if (unlock_dp_on_error)
- xfs_iunlock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
+ xfs_iunlock(dp, XFS_ILOCK_EXCL);
return error;
}
@@ -1466,11 +1458,10 @@ xfs_link(
if (error)
goto std_return;
- xfs_ilock(tdp, XFS_IOLOCK_EXCL | XFS_IOLOCK_PARENT);
xfs_lock_two_inodes(sip, tdp, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, sip, XFS_ILOCK_EXCL);
- xfs_trans_ijoin(tp, tdp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, tdp, XFS_ILOCK_EXCL);
/*
* If we are using project inheritance, we only allow hard link
@@ -2579,10 +2570,9 @@ xfs_remove(
goto std_return;
}
- xfs_ilock(dp, XFS_IOLOCK_EXCL | XFS_IOLOCK_PARENT);
xfs_lock_two_inodes(dp, ip, XFS_ILOCK_EXCL);
- xfs_trans_ijoin(tp, dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
/*
@@ -2963,12 +2953,6 @@ xfs_rename(
* whether the target directory is the same as the source
* directory, we can lock from 2 to 4 inodes.
*/
- if (!new_parent)
- xfs_ilock(src_dp, XFS_IOLOCK_EXCL | XFS_IOLOCK_PARENT);
- else
- xfs_lock_two_inodes(src_dp, target_dp,
- XFS_IOLOCK_EXCL | XFS_IOLOCK_PARENT);
-
xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);
/*
@@ -2976,9 +2960,9 @@ xfs_rename(
* we can rely on either trans_commit or trans_cancel to unlock
* them.
*/
- xfs_trans_ijoin(tp, src_dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);
if (new_parent)
- xfs_trans_ijoin(tp, target_dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);
if (target_ip)
xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);