[PATCH v3 3/3] ocfs2: nowait aio support
From: Gang He
Date: Thu Dec 28 2017 - 05:08:14 EST
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 <ghe@xxxxxxxx>
---
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);
+ 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;
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);
--
1.8.5.6