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 <ghe@suse.com>
Reviewed-by: Alex Chen <alex.chen@huawei.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 32f9c72..b7520e2 100644 (file)
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -1958,7 +1958,7 @@ 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 13fa809..9479f99 100644 (file)
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -2546,13 +2546,18 @@ 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;
        }
 
@@ -2564,9 +2569,14 @@ 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 34139a3..256e0a9 100644 (file)
--- a/fs/ocfs2/dlmglue.h
+++ b/fs/ocfs2/dlmglue.h
@@ -146,7 +146,7 @@ int ocfs2_try_open_lock(struct inode *inode, int write);
 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..5d1784a 100644 (file)
--- 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);

diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index 098f5c7..fb9a20e 100644 (file)
--- 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 (file)
--- a/fs/ocfs2/ocfs2_trace.h
+++ b/fs/ocfs2/ocfs2_trace.h
@@ -1449,20 +1449,22 @@ DEFINE_OCFS2_ULL_ULL_ULL_EVENT(ocfs2_remove_inode_range);
 
 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);