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Merge branch 'xfs-mmap-lock' into for-next
This commit is contained in:
Dave Chinner
commit
88e8fda99a
8 changed files with 216 additions and 113 deletions
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@ -117,24 +117,34 @@ xfs_ilock_attr_map_shared(
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}
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/*
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* The xfs inode contains 2 locks: a multi-reader lock called the
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* i_iolock and a multi-reader lock called the i_lock. This routine
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* allows either or both of the locks to be obtained.
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* The xfs inode contains 3 multi-reader locks: the i_iolock the i_mmap_lock and
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* the i_lock. This routine allows various combinations of the locks to be
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* obtained.
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*
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* The 2 locks should always be ordered so that the IO lock is
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* obtained first in order to prevent deadlock.
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* The 3 locks should always be ordered so that the IO lock is obtained first,
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* the mmap lock second and the ilock last in order to prevent deadlock.
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*
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* ip -- the inode being locked
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* lock_flags -- this parameter indicates the inode's locks
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* to be locked. It can be:
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* XFS_IOLOCK_SHARED,
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* XFS_IOLOCK_EXCL,
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* XFS_ILOCK_SHARED,
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* XFS_ILOCK_EXCL,
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* XFS_IOLOCK_SHARED | XFS_ILOCK_SHARED,
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* XFS_IOLOCK_SHARED | XFS_ILOCK_EXCL,
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* XFS_IOLOCK_EXCL | XFS_ILOCK_SHARED,
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* XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL
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* Basic locking order:
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*
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* i_iolock -> i_mmap_lock -> page_lock -> i_ilock
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*
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* mmap_sem locking order:
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*
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* i_iolock -> page lock -> mmap_sem
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* mmap_sem -> i_mmap_lock -> page_lock
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*
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* The difference in mmap_sem locking order mean that we cannot hold the
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* i_mmap_lock over syscall based read(2)/write(2) based IO. These IO paths can
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* fault in pages during copy in/out (for buffered IO) or require the mmap_sem
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* in get_user_pages() to map the user pages into the kernel address space for
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* direct IO. Similarly the i_iolock cannot be taken inside a page fault because
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* page faults already hold the mmap_sem.
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*
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* Hence to serialise fully against both syscall and mmap based IO, we need to
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* take both the i_iolock and the i_mmap_lock. These locks should *only* be both
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* taken in places where we need to invalidate the page cache in a race
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* free manner (e.g. truncate, hole punch and other extent manipulation
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* functions).
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*/
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void
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xfs_ilock(
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@ -150,6 +160,8 @@ xfs_ilock(
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*/
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ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
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(XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
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ASSERT((lock_flags & (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL)) !=
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(XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL));
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ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
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(XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
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ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);
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@ -159,6 +171,11 @@ xfs_ilock(
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else if (lock_flags & XFS_IOLOCK_SHARED)
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mraccess_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));
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if (lock_flags & XFS_MMAPLOCK_EXCL)
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mrupdate_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
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else if (lock_flags & XFS_MMAPLOCK_SHARED)
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mraccess_nested(&ip->i_mmaplock, XFS_MMAPLOCK_DEP(lock_flags));
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if (lock_flags & XFS_ILOCK_EXCL)
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mrupdate_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
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else if (lock_flags & XFS_ILOCK_SHARED)
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@ -191,6 +208,8 @@ xfs_ilock_nowait(
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*/
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ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
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(XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
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ASSERT((lock_flags & (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL)) !=
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(XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL));
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ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
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(XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
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ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);
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@ -202,21 +221,35 @@ xfs_ilock_nowait(
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if (!mrtryaccess(&ip->i_iolock))
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goto out;
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}
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if (lock_flags & XFS_MMAPLOCK_EXCL) {
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if (!mrtryupdate(&ip->i_mmaplock))
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goto out_undo_iolock;
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} else if (lock_flags & XFS_MMAPLOCK_SHARED) {
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if (!mrtryaccess(&ip->i_mmaplock))
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goto out_undo_iolock;
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}
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if (lock_flags & XFS_ILOCK_EXCL) {
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if (!mrtryupdate(&ip->i_lock))
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goto out_undo_iolock;
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goto out_undo_mmaplock;
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} else if (lock_flags & XFS_ILOCK_SHARED) {
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if (!mrtryaccess(&ip->i_lock))
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goto out_undo_iolock;
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goto out_undo_mmaplock;
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}
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return 1;
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out_undo_iolock:
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out_undo_mmaplock:
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if (lock_flags & XFS_MMAPLOCK_EXCL)
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mrunlock_excl(&ip->i_mmaplock);
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else if (lock_flags & XFS_MMAPLOCK_SHARED)
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mrunlock_shared(&ip->i_mmaplock);
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out_undo_iolock:
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if (lock_flags & XFS_IOLOCK_EXCL)
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mrunlock_excl(&ip->i_iolock);
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else if (lock_flags & XFS_IOLOCK_SHARED)
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mrunlock_shared(&ip->i_iolock);
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out:
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out:
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return 0;
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}
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@ -244,6 +277,8 @@ xfs_iunlock(
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*/
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ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
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(XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
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ASSERT((lock_flags & (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL)) !=
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(XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL));
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ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
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(XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
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ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);
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@ -254,6 +289,11 @@ xfs_iunlock(
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else if (lock_flags & XFS_IOLOCK_SHARED)
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mrunlock_shared(&ip->i_iolock);
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if (lock_flags & XFS_MMAPLOCK_EXCL)
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mrunlock_excl(&ip->i_mmaplock);
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else if (lock_flags & XFS_MMAPLOCK_SHARED)
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mrunlock_shared(&ip->i_mmaplock);
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if (lock_flags & XFS_ILOCK_EXCL)
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mrunlock_excl(&ip->i_lock);
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else if (lock_flags & XFS_ILOCK_SHARED)
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@ -271,11 +311,14 @@ xfs_ilock_demote(
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xfs_inode_t *ip,
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uint lock_flags)
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{
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ASSERT(lock_flags & (XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL));
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ASSERT((lock_flags & ~(XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);
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ASSERT(lock_flags & (XFS_IOLOCK_EXCL|XFS_MMAPLOCK_EXCL|XFS_ILOCK_EXCL));
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ASSERT((lock_flags &
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~(XFS_IOLOCK_EXCL|XFS_MMAPLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);
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if (lock_flags & XFS_ILOCK_EXCL)
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mrdemote(&ip->i_lock);
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if (lock_flags & XFS_MMAPLOCK_EXCL)
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mrdemote(&ip->i_mmaplock);
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if (lock_flags & XFS_IOLOCK_EXCL)
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mrdemote(&ip->i_iolock);
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@ -294,6 +337,12 @@ xfs_isilocked(
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return rwsem_is_locked(&ip->i_lock.mr_lock);
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}
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if (lock_flags & (XFS_MMAPLOCK_EXCL|XFS_MMAPLOCK_SHARED)) {
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if (!(lock_flags & XFS_MMAPLOCK_SHARED))
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return !!ip->i_mmaplock.mr_writer;
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return rwsem_is_locked(&ip->i_mmaplock.mr_lock);
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}
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if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
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if (!(lock_flags & XFS_IOLOCK_SHARED))
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return !!ip->i_iolock.mr_writer;
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@ -314,14 +363,27 @@ int xfs_lock_delays;
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#endif
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/*
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* Bump the subclass so xfs_lock_inodes() acquires each lock with
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* a different value
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* Bump the subclass so xfs_lock_inodes() acquires each lock with a different
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* value. This shouldn't be called for page fault locking, but we also need to
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* ensure we don't overrun the number of lockdep subclasses for the iolock or
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* mmaplock as that is limited to 12 by the mmap lock lockdep annotations.
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*/
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static inline int
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xfs_lock_inumorder(int lock_mode, int subclass)
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{
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if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL))
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if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)) {
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ASSERT(subclass + XFS_LOCK_INUMORDER <
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(1 << (XFS_MMAPLOCK_SHIFT - XFS_IOLOCK_SHIFT)));
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lock_mode |= (subclass + XFS_LOCK_INUMORDER) << XFS_IOLOCK_SHIFT;
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}
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if (lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) {
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ASSERT(subclass + XFS_LOCK_INUMORDER <
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(1 << (XFS_ILOCK_SHIFT - XFS_MMAPLOCK_SHIFT)));
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lock_mode |= (subclass + XFS_LOCK_INUMORDER) <<
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XFS_MMAPLOCK_SHIFT;
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}
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if (lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL))
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lock_mode |= (subclass + XFS_LOCK_INUMORDER) << XFS_ILOCK_SHIFT;
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@ -440,10 +502,10 @@ again:
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}
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/*
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* xfs_lock_two_inodes() can only be used to lock one type of lock
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* at a time - the iolock or the ilock, but not both at once. If
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* we lock both at once, lockdep will report false positives saying
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* we have violated locking orders.
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* xfs_lock_two_inodes() can only be used to lock one type of lock at a time -
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* the iolock, the mmaplock or the ilock, but not more than one at a time. If we
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* lock more than one at a time, lockdep will report false positives saying we
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* have violated locking orders.
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*/
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void
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xfs_lock_two_inodes(
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@ -455,8 +517,12 @@ xfs_lock_two_inodes(
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int attempts = 0;
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xfs_log_item_t *lp;
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if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL))
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ASSERT((lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)) == 0);
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if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)) {
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ASSERT(!(lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)));
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ASSERT(!(lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
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} else if (lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL))
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ASSERT(!(lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
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ASSERT(ip0->i_ino != ip1->i_ino);
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if (ip0->i_ino > ip1->i_ino) {
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