Hi Alex,
>>> > Hi Gang, > > On 2017/12/28 18:07, Gang He wrote: >> Return -EAGAIN if any of the following checks fail for >> direct I/O with nowait flag: >> Can not get the related locks immediately, >> Blocks are not allocated at the write location, it will trigger >> block allocation, this will block IO operations. >> >> Signed-off-by: Gang He <[email protected]> >> --- >> fs/ocfs2/dir.c | 2 +- >> fs/ocfs2/dlmglue.c | 20 ++++++++--- >> fs/ocfs2/dlmglue.h | 2 +- >> fs/ocfs2/file.c | 95 >> +++++++++++++++++++++++++++++++++++++++----------- >> fs/ocfs2/mmap.c | 2 +- >> fs/ocfs2/ocfs2_trace.h | 10 +++--- >> 6 files changed, 99 insertions(+), 32 deletions(-) >> >> diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c >> index febe631..ea50901 100644 >> --- a/fs/ocfs2/dir.c >> +++ b/fs/ocfs2/dir.c >> @@ -1957,7 +1957,7 @@ int ocfs2_readdir(struct file *file, struct >> dir_context > *ctx) >> >> trace_ocfs2_readdir((unsigned long long)OCFS2_I(inode)->ip_blkno); >> >> - error = ocfs2_inode_lock_atime(inode, file->f_path.mnt, &lock_level); >> + error = ocfs2_inode_lock_atime(inode, file->f_path.mnt, &lock_level, 1); >> if (lock_level && error >= 0) { >> /* We release EX lock which used to update atime >> * and get PR lock again to reduce contention >> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c >> index a68efa3..07e169f 100644 >> --- a/fs/ocfs2/dlmglue.c >> +++ b/fs/ocfs2/dlmglue.c >> @@ -2515,13 +2515,18 @@ int ocfs2_inode_lock_with_page(struct inode *inode, >> >> int ocfs2_inode_lock_atime(struct inode *inode, >> struct vfsmount *vfsmnt, >> - int *level) >> + int *level, int wait) >> { >> int ret; >> >> - ret = ocfs2_inode_lock(inode, NULL, 0); >> + if (wait) >> + ret = ocfs2_inode_lock(inode, NULL, 0); >> + else >> + ret = ocfs2_try_inode_lock(inode, NULL, 0); >> + >> if (ret < 0) { >> - mlog_errno(ret); >> + if (ret != -EAGAIN) >> + mlog_errno(ret); >> return ret; >> } >> >> @@ -2533,9 +2538,14 @@ int ocfs2_inode_lock_atime(struct inode *inode, >> struct buffer_head *bh = NULL; >> >> ocfs2_inode_unlock(inode, 0); >> - ret = ocfs2_inode_lock(inode, &bh, 1); >> + if (wait) >> + ret = ocfs2_inode_lock(inode, &bh, 1); >> + else >> + ret = ocfs2_try_inode_lock(inode, &bh, 1); >> + >> if (ret < 0) { >> - mlog_errno(ret); >> + if (ret != -EAGAIN) >> + mlog_errno(ret); >> return ret; >> } >> *level = 1; >> diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h >> index 05910fc..c83dbb5 100644 >> --- a/fs/ocfs2/dlmglue.h >> +++ b/fs/ocfs2/dlmglue.h >> @@ -123,7 +123,7 @@ void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res > *lockres, >> void ocfs2_open_unlock(struct inode *inode); >> int ocfs2_inode_lock_atime(struct inode *inode, >> struct vfsmount *vfsmnt, >> - int *level); >> + int *level, int wait); >> int ocfs2_inode_lock_full_nested(struct inode *inode, >> struct buffer_head **ret_bh, >> int ex, >> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c >> index a1d0510..caef9b1 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 @@ static int ocfs2_prepare_inode_for_refcount(struct > inode *inode, >> } >> >> 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 @@ static int ocfs2_prepare_inode_for_write(struct file > *file, >> 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); > I think we only need check the nowait here because we already check if the > 'IOCB_DIRECT' > flag and the 'IOCB_NOWAIT' flag are both set in the front of this function. Yes. > >> + if (direct_io && 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 (direct_io && 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 +2402,7 @@ 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 nowait = iocb->ki_flags & IOCB_NOWAIT ? 1 : 0; >> > Here should we check if the 'IOCB_DIRECT' flag and the 'IOCB_NOWAIT' flag > are both set? Ok, I will look at the code again, make the code style consistent. Thanks Gang > > Thanks, > Alex > >> trace_ocfs2_file_aio_read(inode, filp, filp->f_path.dentry, >> (unsigned long long)OCFS2_I(inode)->ip_blkno, >> @@ -2374,9 +2422,14 @@ static ssize_t ocfs2_file_read_iter(struct kiocb > *iocb, >> * need locks to protect pending reads from racing with truncate. >> */ >> if (iocb->ki_flags & IOCB_DIRECT) { >> - ret = ocfs2_rw_lock(inode, 0); >> + 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 +2446,11 @@ 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); >> diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c >> index 098f5c7..fb9a20e 100644 >> --- a/fs/ocfs2/mmap.c >> +++ b/fs/ocfs2/mmap.c >> @@ -184,7 +184,7 @@ int ocfs2_mmap(struct file *file, struct vm_area_struct > *vma) >> int ret = 0, lock_level = 0; >> >> ret = ocfs2_inode_lock_atime(file_inode(file), >> - file->f_path.mnt, &lock_level); >> + file->f_path.mnt, &lock_level, 1); >> if (ret < 0) { >> mlog_errno(ret); >> goto out; >> diff --git a/fs/ocfs2/ocfs2_trace.h b/fs/ocfs2/ocfs2_trace.h >> index a0b5d00..e2a11aa 100644 >> --- a/fs/ocfs2/ocfs2_trace.h >> +++ b/fs/ocfs2/ocfs2_trace.h >> @@ -1449,20 +1449,22 @@ >> >> TRACE_EVENT(ocfs2_prepare_inode_for_write, >> TP_PROTO(unsigned long long ino, unsigned long long saved_pos, >> - unsigned long count), >> - TP_ARGS(ino, saved_pos, count), >> + unsigned long count, int wait), >> + TP_ARGS(ino, saved_pos, count, wait), >> TP_STRUCT__entry( >> __field(unsigned long long, ino) >> __field(unsigned long long, saved_pos) >> __field(unsigned long, count) >> + __field(int, wait) >> ), >> TP_fast_assign( >> __entry->ino = ino; >> __entry->saved_pos = saved_pos; >> __entry->count = count; >> + __entry->wait = wait; >> ), >> - TP_printk("%llu %llu %lu", __entry->ino, >> - __entry->saved_pos, __entry->count) >> + TP_printk("%llu %llu %lu %d", __entry->ino, >> + __entry->saved_pos, __entry->count, __entry->wait) >> ); >> >> DEFINE_OCFS2_INT_EVENT(generic_file_aio_read_ret); >>
