[PATCH v5 5/7] xfs: add RWF_NONBLOCK support
From: Milosz Tanski <hidden>
Date: 2014-11-05 21:14:51
Also in:
linux-api, linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
From: Christoph Hellwig <hch@lst.de> Add support for non-blocking reads. The guts are handled by the generic code, the only addition is a non-blocking variant of xfs_rw_ilock. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/xfs_file.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index b1f6334..0655915 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c@@ -61,6 +61,25 @@ xfs_rw_ilock( xfs_ilock(ip, type); } +static inline bool +xfs_rw_ilock_nowait( + struct xfs_inode *ip, + int type) +{ + if (type & XFS_IOLOCK_EXCL) { + if (!mutex_trylock(&VFS_I(ip)->i_mutex)) + return false; + if (!xfs_ilock_nowait(ip, type)) { + mutex_unlock(&VFS_I(ip)->i_mutex); + return false; + } + } else { + if (!xfs_ilock_nowait(ip, type)) + return false; + } + return true; +} + static inline void xfs_rw_iunlock( struct xfs_inode *ip,
@@ -246,10 +265,6 @@ xfs_file_read_iter( XFS_STATS_INC(xs_read_calls); - /* XXX: need a non-blocking iolock helper, shouldn't be too hard */ - if (iocb->ki_rwflags & RWF_NONBLOCK) - return -EAGAIN; - if (unlikely(file->f_flags & O_DIRECT)) ioflags |= XFS_IO_ISDIRECT; if (file->f_mode & FMODE_NOCMTIME)
@@ -287,7 +302,14 @@ xfs_file_read_iter( * This allows the normal direct IO case of no page cache pages to * proceeed concurrently without serialisation. */ - xfs_rw_ilock(ip, XFS_IOLOCK_SHARED); + if (iocb->ki_rwflags & RWF_NONBLOCK) { + if (ioflags & XFS_IO_ISDIRECT) + return -EAGAIN; + if (!xfs_rw_ilock_nowait(ip, XFS_IOLOCK_SHARED)) + return -EAGAIN; + } else { + xfs_rw_ilock(ip, XFS_IOLOCK_SHARED); + } if ((ioflags & XFS_IO_ISDIRECT) && inode->i_mapping->nrpages) { xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED); xfs_rw_ilock(ip, XFS_IOLOCK_EXCL);
--
1.9.1
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