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@ -132,7 +132,7 @@ xfs_ilock_attr_map_shared(
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/*
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* In addition to i_rwsem in the VFS inode, the xfs inode contains 2
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* multi-reader locks: i_mmap_lock and the i_lock. This routine allows
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* multi-reader locks: invalidate_lock and the i_lock. This routine allows
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* various combinations of the locks to be obtained.
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*
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* The 3 locks should always be ordered so that the IO lock is obtained first,
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@ -140,23 +140,23 @@ xfs_ilock_attr_map_shared(
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*
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* Basic locking order:
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*
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* i_rwsem -> i_mmap_lock -> page_lock -> i_ilock
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* i_rwsem -> invalidate_lock -> page_lock -> i_ilock
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*
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* mmap_lock locking order:
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*
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* i_rwsem -> page lock -> mmap_lock
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* mmap_lock -> i_mmap_lock -> page_lock
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* mmap_lock -> invalidate_lock -> page_lock
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*
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* The difference in mmap_lock 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_lock
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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_rwsem cannot be taken inside a page fault because
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* page faults already hold the mmap_lock.
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* invalidate_lock over syscall based read(2)/write(2) based IO. These IO paths
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* can fault in pages during copy in/out (for buffered IO) or require the
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* mmap_lock in get_user_pages() to map the user pages into the kernel address
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* space for direct IO. Similarly the i_rwsem cannot be taken inside a page
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* fault because page faults already hold the mmap_lock.
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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_rwsem 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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* take both the i_rwsem and the invalidate_lock. These locks should *only* be
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* both 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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@ -188,10 +188,13 @@ xfs_ilock(
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XFS_IOLOCK_DEP(lock_flags));
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}
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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_MMAPLOCK_EXCL) {
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down_write_nested(&VFS_I(ip)->i_mapping->invalidate_lock,
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XFS_MMAPLOCK_DEP(lock_flags));
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} else if (lock_flags & XFS_MMAPLOCK_SHARED) {
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down_read_nested(&VFS_I(ip)->i_mapping->invalidate_lock,
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XFS_MMAPLOCK_DEP(lock_flags));
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}
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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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@ -240,10 +243,10 @@ xfs_ilock_nowait(
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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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if (!down_write_trylock(&VFS_I(ip)->i_mapping->invalidate_lock))
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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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if (!down_read_trylock(&VFS_I(ip)->i_mapping->invalidate_lock))
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goto out_undo_iolock;
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}
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@ -258,9 +261,9 @@ xfs_ilock_nowait(
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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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up_write(&VFS_I(ip)->i_mapping->invalidate_lock);
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else if (lock_flags & XFS_MMAPLOCK_SHARED)
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mrunlock_shared(&ip->i_mmaplock);
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up_read(&VFS_I(ip)->i_mapping->invalidate_lock);
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out_undo_iolock:
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if (lock_flags & XFS_IOLOCK_EXCL)
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up_write(&VFS_I(ip)->i_rwsem);
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@ -307,9 +310,9 @@ xfs_iunlock(
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up_read(&VFS_I(ip)->i_rwsem);
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if (lock_flags & XFS_MMAPLOCK_EXCL)
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mrunlock_excl(&ip->i_mmaplock);
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up_write(&VFS_I(ip)->i_mapping->invalidate_lock);
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else if (lock_flags & XFS_MMAPLOCK_SHARED)
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mrunlock_shared(&ip->i_mmaplock);
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up_read(&VFS_I(ip)->i_mapping->invalidate_lock);
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if (lock_flags & XFS_ILOCK_EXCL)
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mrunlock_excl(&ip->i_lock);
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@ -335,7 +338,7 @@ xfs_ilock_demote(
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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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downgrade_write(&VFS_I(ip)->i_mapping->invalidate_lock);
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if (lock_flags & XFS_IOLOCK_EXCL)
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downgrade_write(&VFS_I(ip)->i_rwsem);
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@ -375,9 +378,8 @@ xfs_isilocked(
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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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return __xfs_rwsem_islocked(&VFS_I(ip)->i_rwsem,
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(lock_flags & XFS_IOLOCK_SHARED));
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}
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if (lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) {
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