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| author | Dan Williams <dan.j.williams@intel.com> | 2018-03-20 14:42:38 -0700 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2018-05-22 07:19:08 -0700 |
| commit | 69eb5fa10eb283e9fcae3ce6f8aaf103b8f0c28d (patch) | |
| tree | 6ce4847f9262431cc501581d1c43358d116f6c5d /fs/xfs/xfs_pnfs.c | |
| parent | c63a8eae63d3859c9c7067aa239a4cfd7423a665 (diff) | |
| download | linux-69eb5fa10eb283e9fcae3ce6f8aaf103b8f0c28d.tar.bz2 | |
xfs: prepare xfs_break_layouts() for another layout type
When xfs is operating as the back-end of a pNFS block server, it
prevents collisions between local and remote operations by requiring a
lease to be held for remotely accessed blocks. Local filesystem
operations break those leases before writing or mutating the extent map
of the file.
A similar mechanism is needed to prevent operations on pinned dax
mappings, like device-DMA, from colliding with extent unmap operations.
BREAK_WRITE and BREAK_UNMAP are introduced as two distinct levels of
layout breaking.
Layouts are broken in the BREAK_WRITE case to ensure that layout-holders
do not collide with local writes. Additionally, layouts are broken in
the BREAK_UNMAP case to make sure the layout-holder has a consistent
view of the file's extent map. While BREAK_WRITE breaks can be satisfied
be recalling FL_LAYOUT leases, BREAK_UNMAP breaks additionally require
waiting for busy dax-pages to go idle while holding XFS_MMAPLOCK_EXCL.
After this refactoring xfs_break_layouts() becomes the entry point for
coordinating both types of breaks. Finally, xfs_break_leased_layouts()
becomes just the BREAK_WRITE handler.
Note that the unlock tracking is needed in a follow on change. That will
coordinate retrying either break handler until both successfully test
for a lease break while maintaining the lock state.
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Reported-by: Dave Chinner <david@fromorbit.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'fs/xfs/xfs_pnfs.c')
| -rw-r--r-- | fs/xfs/xfs_pnfs.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c index 6ea7b0b55d02..f44c3599527d 100644 --- a/fs/xfs/xfs_pnfs.c +++ b/fs/xfs/xfs_pnfs.c @@ -31,17 +31,17 @@ * rules in the page fault path we don't bother. */ int -xfs_break_layouts( +xfs_break_leased_layouts( struct inode *inode, - uint *iolock) + uint *iolock, + bool *did_unlock) { struct xfs_inode *ip = XFS_I(inode); int error; - ASSERT(xfs_isilocked(ip, XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)); - while ((error = break_layout(inode, false) == -EWOULDBLOCK)) { xfs_iunlock(ip, *iolock); + *did_unlock = true; error = break_layout(inode, true); *iolock &= ~XFS_IOLOCK_SHARED; *iolock |= XFS_IOLOCK_EXCL; @@ -121,8 +121,8 @@ xfs_fs_map_blocks( * Lock out any other I/O before we flush and invalidate the pagecache, * and then hand out a layout to the remote system. This is very * similar to direct I/O, except that the synchronization is much more - * complicated. See the comment near xfs_break_layouts for a detailed - * explanation. + * complicated. See the comment near xfs_break_leased_layouts + * for a detailed explanation. */ xfs_ilock(ip, XFS_IOLOCK_EXCL); |