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Subject[PATCH 3/3] ocfs2: nowait aio support
Date
Return EAGAIN if any of the following checks fail for direct I/O:
Can not get the related locks immediately,
Blocks are not allocated at the write location, it will trigger
block allocation and block IO operations.

Signed-off-by: Gang He <ghe@suse.com>
---
fs/ocfs2/dir.c | 2 +-
fs/ocfs2/dlmglue.c | 20 ++++++++++----
fs/ocfs2/dlmglue.h | 2 +-
fs/ocfs2/file.c | 74 +++++++++++++++++++++++++++++++++++++-------------
fs/ocfs2/mmap.c | 2 +-
fs/ocfs2/ocfs2_trace.h | 10 ++++---
6 files changed, 79 insertions(+), 31 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 5cfbd04..feb8dbe 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -2516,13 +2516,18 @@ 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;
}

@@ -2534,9 +2539,14 @@ 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 dc455d4..900f04e 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;
}
@@ -2132,8 +2134,7 @@ 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;
struct dentry *dentry = file->f_path.dentry;
@@ -2145,10 +2146,14 @@ 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, NULL, meta_level);
if (ret < 0) {
meta_level = -1;
- mlog_errno(ret);
+ if (ret != -EAGAIN)
+ mlog_errno(ret);
goto out;
}

@@ -2199,7 +2204,7 @@ 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);

if (meta_level >= 0)
ocfs2_inode_unlock(inode, meta_level);
@@ -2211,7 +2216,7 @@ 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 +2228,8 @@ 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 +2237,17 @@ 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 +2256,13 @@ 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 +2276,13 @@ 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 +2297,17 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
}
count = ret;

- ret = ocfs2_prepare_inode_for_write(file, iocb->ki_pos, count);
+ if (direct_io && nowait) {
+ if (!ocfs2_overwrite_io(inode, iocb->ki_pos, count, 0)) {
+ ret = -EAGAIN;
+ goto out;
+ }
+ }
+
+ 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 +2383,7 @@ 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 +2403,14 @@ 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 +2427,11 @@ 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
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