diff options
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_file.c | |
parent | c63a8eae63d3859c9c7067aa239a4cfd7423a665 (diff) | |
download | linux-69eb5fa10eb283e9fcae3ce6f8aaf103b8f0c28d.tar.gz linux-69eb5fa10eb283e9fcae3ce6f8aaf103b8f0c28d.tar.bz2 linux-69eb5fa10eb283e9fcae3ce6f8aaf103b8f0c28d.zip |
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_file.c')
-rw-r--r-- | fs/xfs/xfs_file.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 35309bd046be..4774c7172ef4 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -312,7 +312,7 @@ restart: if (error <= 0) return error; - error = xfs_break_layouts(inode, iolock); + error = xfs_break_layouts(inode, iolock, BREAK_WRITE); if (error) return error; @@ -718,6 +718,28 @@ buffered: return ret; } +int +xfs_break_layouts( + struct inode *inode, + uint *iolock, + enum layout_break_reason reason) +{ + bool retry; + + ASSERT(xfs_isilocked(XFS_I(inode), XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)); + + switch (reason) { + case BREAK_UNMAP: + ASSERT(xfs_isilocked(XFS_I(inode), XFS_MMAPLOCK_EXCL)); + /* fall through */ + case BREAK_WRITE: + return xfs_break_leased_layouts(inode, iolock, &retry); + default: + WARN_ON_ONCE(1); + return -EINVAL; + } +} + #define XFS_FALLOC_FL_SUPPORTED \ (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | \ @@ -744,7 +766,7 @@ xfs_file_fallocate( return -EOPNOTSUPP; xfs_ilock(ip, iolock); - error = xfs_break_layouts(inode, &iolock); + error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP); if (error) goto out_unlock; |