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xfs: pull up iolock from xfs_free_eofblocks()

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xfs_free_eofblocks() requires the IOLOCK_EXCL lock, but is called from
different contexts where the lock may or may not be held. The
need_iolock parameter exists for this reason, to indicate whether
xfs_free_eofblocks() must acquire the iolock itself before it can
proceed.

This is ugly and confusing. Simplify the semantics of
xfs_free_eofblocks() to require the caller to acquire the iolock
appropriately and kill the need_iolock parameter. While here, the mp
param can be removed as well as the xfs_mount is accessible from the
xfs_inode structure. This patch does not change behavior.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Brian Foster
2017-01-27 23:22:55 -08:00
committed by Darrick J. Wong
parent 64f61ab604
commit a36b926180
4 changed files with 61 additions and 60 deletions
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53
fs/xfs/xfs_inode.c
View File

@@ -1692,32 +1692,34 @@ xfs_release(
if (xfs_can_free_eofblocks(ip, false)) {
/*
* If we can't get the iolock just skip truncating the blocks
* past EOF because we could deadlock with the mmap_sem
* otherwise. We'll get another chance to drop them once the
* last reference to the inode is dropped, so we'll never leak
* blocks permanently.
* Check if the inode is being opened, written and closed
* frequently and we have delayed allocation blocks outstanding
* (e.g. streaming writes from the NFS server), truncating the
* blocks past EOF will cause fragmentation to occur.
*
* Further, check if the inode is being opened, written and
* closed frequently and we have delayed allocation blocks
* outstanding (e.g. streaming writes from the NFS server),
* truncating the blocks past EOF will cause fragmentation to
* occur.
*
* In this case don't do the truncation, either, but we have to
* be careful how we detect this case. Blocks beyond EOF show
* up as i_delayed_blks even when the inode is clean, so we
* need to truncate them away first before checking for a dirty
* release. Hence on the first dirty close we will still remove
* the speculative allocation, but after that we will leave it
* in place.
* In this case don't do the truncation, but we have to be
* careful how we detect this case. Blocks beyond EOF show up as
* i_delayed_blks even when the inode is clean, so we need to
* truncate them away first before checking for a dirty release.
* Hence on the first dirty close we will still remove the
* speculative allocation, but after that we will leave it in
* place.
*/
if (xfs_iflags_test(ip, XFS_IDIRTY_RELEASE))
return 0;
error = xfs_free_eofblocks(mp, ip, true);
if (error && error != -EAGAIN)
return error;
/*
* If we can't get the iolock just skip truncating the blocks
* past EOF because we could deadlock with the mmap_sem
* otherwise. We'll get another chance to drop them once the
* last reference to the inode is dropped, so we'll never leak
* blocks permanently.
*/
if (xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
error = xfs_free_eofblocks(ip);
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
if (error)
return error;
}
/* delalloc blocks after truncation means it really is dirty */
if (ip->i_delayed_blks)
@@ -1904,8 +1906,11 @@ xfs_inactive(
* cache. Post-eof blocks must be freed, lest we end up with
* broken free space accounting.
*/
if (xfs_can_free_eofblocks(ip, true))
xfs_free_eofblocks(mp, ip, false);
if (xfs_can_free_eofblocks(ip, true)) {
xfs_ilock(ip, XFS_IOLOCK_EXCL);
xfs_free_eofblocks(ip);
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
}
return;
}