diff options
| author | Christoph Hellwig <hch@infradead.org> | 2011-12-18 20:00:09 +0000 |
|---|---|---|
| committer | Ben Myers <bpm@sgi.com> | 2012-01-17 15:06:45 -0600 |
| commit | 474fce067521a40dbacc722e8ba119e81c2d31bf (patch) | |
| tree | fd923aa42a5304182e8a8c64ca5d130f9afef286 /fs/xfs/xfs_iget.c | |
| parent | 49e4c70e52a2bc2090e5a4e003e2888af21d6a2b (diff) | |
| download | linux-stable-474fce067521a40dbacc722e8ba119e81c2d31bf.tar.gz linux-stable-474fce067521a40dbacc722e8ba119e81c2d31bf.tar.bz2 linux-stable-474fce067521a40dbacc722e8ba119e81c2d31bf.zip | |
xfs: replace i_flock with a sleeping bitlock
We almost never block on i_flock, the exception is synchronous inode
flushing. Instead of bloating the inode with a 16/24-byte completion
that we abuse as a semaphore just implement it as a bitlock that uses
a bit waitqueue for the rare sleeping path. This primarily is a
tradeoff between a much smaller inode and a faster non-blocking
path vs faster wakeups, and we are much better off with the former.
A small downside is that we will lose lockdep checking for i_flock, but
given that it's always taken inside the ilock that should be acceptable.
Note that for example the inode writeback locking is implemented in a
very similar way.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_iget.c')
| -rw-r--r-- | fs/xfs/xfs_iget.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c index f180ce896cd7..a7cf7139f9ad 100644 --- a/fs/xfs/xfs_iget.c +++ b/fs/xfs/xfs_iget.c @@ -77,7 +77,7 @@ xfs_inode_alloc( ASSERT(atomic_read(&ip->i_pincount) == 0); ASSERT(!spin_is_locked(&ip->i_flags_lock)); - ASSERT(completion_done(&ip->i_flush)); + ASSERT(!xfs_isiflocked(ip)); ASSERT(ip->i_ino == 0); mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino); @@ -150,7 +150,7 @@ xfs_inode_free( /* asserts to verify all state is correct here */ ASSERT(atomic_read(&ip->i_pincount) == 0); ASSERT(!spin_is_locked(&ip->i_flags_lock)); - ASSERT(completion_done(&ip->i_flush)); + ASSERT(!xfs_isiflocked(ip)); /* * Because we use RCU freeing we need to ensure the inode always @@ -713,3 +713,19 @@ xfs_isilocked( return 0; } #endif + +void +__xfs_iflock( + struct xfs_inode *ip) +{ + wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_IFLOCK_BIT); + DEFINE_WAIT_BIT(wait, &ip->i_flags, __XFS_IFLOCK_BIT); + + do { + prepare_to_wait_exclusive(wq, &wait.wait, TASK_UNINTERRUPTIBLE); + if (xfs_isiflocked(ip)) + io_schedule(); + } while (!xfs_iflock_nowait(ip)); + + finish_wait(wq, &wait.wait); +} |