From c4c2416ab0d656539cca5de4ae0a2ba8ec3d9eca Mon Sep 17 00:00:00 2001 From: Gang He Date: Wed, 31 Jan 2018 16:15:25 -0800 Subject: ocfs2: nowait aio support Return EAGAIN if any of the following checks fail for direct I/O: - Cannot get the related locks immediately - Blocks are not allocated at the write location, it will trigger block allocation and block IO operations. [ghe@suse.com: v4] Link: http://lkml.kernel.org/r/1516007283-29932-4-git-send-email-ghe@suse.com [ghe@suse.com: v2] Link: http://lkml.kernel.org/r/1511944612-9629-4-git-send-email-ghe@suse.com Link: http://lkml.kernel.org/r/1511775987-841-4-git-send-email-ghe@suse.com Signed-off-by: Gang He Reviewed-by: Alex Chen Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Joseph Qi Cc: Changwei Ge Cc: Jun Piao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/file.c | 101 ++++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 80 insertions(+), 21 deletions(-) (limited to 'fs/ocfs2/file.c') diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index a1d051055472..5d1784a365a3 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -140,6 +140,8 @@ static int ocfs2_file_open(struct inode *inode, struct file *file) spin_unlock(&oi->ip_lock); } + file->f_mode |= FMODE_NOWAIT; + leave: return status; } @@ -2132,12 +2134,12 @@ out: } static int ocfs2_prepare_inode_for_write(struct file *file, - loff_t pos, - size_t count) + loff_t pos, size_t count, int wait) { - int ret = 0, meta_level = 0; + int ret = 0, meta_level = 0, overwrite_io = 0; struct dentry *dentry = file->f_path.dentry; struct inode *inode = d_inode(dentry); + struct buffer_head *di_bh = NULL; loff_t end; /* @@ -2145,13 +2147,40 @@ static int ocfs2_prepare_inode_for_write(struct file *file, * if we need to make modifications here. */ for(;;) { - ret = ocfs2_inode_lock(inode, NULL, meta_level); + if (wait) + ret = ocfs2_inode_lock(inode, NULL, meta_level); + else + ret = ocfs2_try_inode_lock(inode, + overwrite_io ? NULL : &di_bh, meta_level); if (ret < 0) { meta_level = -1; - mlog_errno(ret); + if (ret != -EAGAIN) + mlog_errno(ret); goto out; } + /* + * Check if IO will overwrite allocated blocks in case + * IOCB_NOWAIT flag is set. + */ + if (!wait && !overwrite_io) { + overwrite_io = 1; + if (!down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem)) { + ret = -EAGAIN; + goto out_unlock; + } + + ret = ocfs2_overwrite_io(inode, di_bh, pos, count); + brelse(di_bh); + di_bh = NULL; + up_read(&OCFS2_I(inode)->ip_alloc_sem); + if (ret < 0) { + if (ret != -EAGAIN) + mlog_errno(ret); + goto out_unlock; + } + } + /* Clear suid / sgid if necessary. We do this here * instead of later in the write path because * remove_suid() calls ->setattr without any hint that @@ -2199,7 +2228,9 @@ static int ocfs2_prepare_inode_for_write(struct file *file, out_unlock: trace_ocfs2_prepare_inode_for_write(OCFS2_I(inode)->ip_blkno, - pos, count); + pos, count, wait); + + brelse(di_bh); if (meta_level >= 0) ocfs2_inode_unlock(inode, meta_level); @@ -2211,7 +2242,7 @@ out: static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { - int direct_io, rw_level; + int rw_level; ssize_t written = 0; ssize_t ret; size_t count = iov_iter_count(from); @@ -2223,6 +2254,8 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, void *saved_ki_complete = NULL; int append_write = ((iocb->ki_pos + count) >= i_size_read(inode) ? 1 : 0); + int direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0; + int nowait = iocb->ki_flags & IOCB_NOWAIT ? 1 : 0; trace_ocfs2_file_aio_write(inode, file, file->f_path.dentry, (unsigned long long)OCFS2_I(inode)->ip_blkno, @@ -2230,12 +2263,17 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, file->f_path.dentry->d_name.name, (unsigned int)from->nr_segs); /* GRRRRR */ + if (!direct_io && nowait) + return -EOPNOTSUPP; + if (count == 0) return 0; - direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0; - - inode_lock(inode); + if (nowait) { + if (!inode_trylock(inode)) + return -EAGAIN; + } else + inode_lock(inode); /* * Concurrent O_DIRECT writes are allowed with @@ -2244,9 +2282,13 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, */ rw_level = (!direct_io || full_coherency || append_write); - ret = ocfs2_rw_lock(inode, rw_level); + if (nowait) + ret = ocfs2_try_rw_lock(inode, rw_level); + else + ret = ocfs2_rw_lock(inode, rw_level); if (ret < 0) { - mlog_errno(ret); + if (ret != -EAGAIN) + mlog_errno(ret); goto out_mutex; } @@ -2260,9 +2302,13 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, * other nodes to drop their caches. Buffered I/O * already does this in write_begin(). */ - ret = ocfs2_inode_lock(inode, NULL, 1); + if (nowait) + ret = ocfs2_try_inode_lock(inode, NULL, 1); + else + ret = ocfs2_inode_lock(inode, NULL, 1); if (ret < 0) { - mlog_errno(ret); + if (ret != -EAGAIN) + mlog_errno(ret); goto out; } @@ -2277,9 +2323,10 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, } count = ret; - ret = ocfs2_prepare_inode_for_write(file, iocb->ki_pos, count); + ret = ocfs2_prepare_inode_for_write(file, iocb->ki_pos, count, !nowait); if (ret < 0) { - mlog_errno(ret); + if (ret != -EAGAIN) + mlog_errno(ret); goto out; } @@ -2355,6 +2402,8 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, int ret = 0, rw_level = -1, lock_level = 0; struct file *filp = iocb->ki_filp; struct inode *inode = file_inode(filp); + int direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0; + int nowait = iocb->ki_flags & IOCB_NOWAIT ? 1 : 0; trace_ocfs2_file_aio_read(inode, filp, filp->f_path.dentry, (unsigned long long)OCFS2_I(inode)->ip_blkno, @@ -2369,14 +2418,22 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, goto bail; } + if (!direct_io && nowait) + return -EOPNOTSUPP; + /* * buffered reads protect themselves in ->readpage(). O_DIRECT reads * need locks to protect pending reads from racing with truncate. */ - if (iocb->ki_flags & IOCB_DIRECT) { - ret = ocfs2_rw_lock(inode, 0); + if (direct_io) { + if (nowait) + ret = ocfs2_try_rw_lock(inode, 0); + else + ret = ocfs2_rw_lock(inode, 0); + if (ret < 0) { - mlog_errno(ret); + if (ret != -EAGAIN) + mlog_errno(ret); goto bail; } rw_level = 0; @@ -2393,9 +2450,11 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, * like i_size. This allows the checks down below * generic_file_aio_read() a chance of actually working. */ - ret = ocfs2_inode_lock_atime(inode, filp->f_path.mnt, &lock_level); + ret = ocfs2_inode_lock_atime(inode, filp->f_path.mnt, &lock_level, + !nowait); if (ret < 0) { - mlog_errno(ret); + if (ret != -EAGAIN) + mlog_errno(ret); goto bail; } ocfs2_inode_unlock(inode, lock_level); -- cgit v1.2.3