gfs2: iomap direct I/O support
The page unmapping previously done in gfs2_direct_IO is now done
generically in iomap_dio_rw.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Bob Peterson <rpeterso@redhat.com>
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 16dd395..8928051 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -690,6 +690,85 @@ static int gfs2_fsync(struct file *file, loff_t start, loff_t end,
return ret ? ret : ret1;
}
+static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct file *file = iocb->ki_filp;
+ struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
+ size_t count = iov_iter_count(to);
+ struct gfs2_holder gh;
+ ssize_t ret;
+
+ if (!count)
+ return 0; /* skip atime */
+
+ gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
+ ret = gfs2_glock_nq(&gh);
+ if (ret)
+ goto out_uninit;
+
+ /* fall back to buffered I/O for stuffed files */
+ ret = -ENOTBLK;
+ if (gfs2_is_stuffed(ip))
+ goto out;
+
+ ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL);
+
+out:
+ gfs2_glock_dq(&gh);
+out_uninit:
+ gfs2_holder_uninit(&gh);
+ return ret;
+}
+
+static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file->f_mapping->host;
+ struct gfs2_inode *ip = GFS2_I(inode);
+ size_t len = iov_iter_count(from);
+ loff_t offset = iocb->ki_pos;
+ struct gfs2_holder gh;
+ ssize_t ret;
+
+ /*
+ * Deferred lock, even if its a write, since we do no allocation on
+ * this path. All we need to change is the atime, and this lock mode
+ * ensures that other nodes have flushed their buffered read caches
+ * (i.e. their page cache entries for this inode). We do not,
+ * unfortunately, have the option of only flushing a range like the
+ * VFS does.
+ */
+ gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
+ ret = gfs2_glock_nq(&gh);
+ if (ret)
+ goto out_uninit;
+
+ /* Silently fall back to buffered I/O when writing beyond EOF */
+ if (offset + len > i_size_read(&ip->i_inode))
+ goto out;
+
+ ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL);
+
+out:
+ gfs2_glock_dq(&gh);
+out_uninit:
+ gfs2_holder_uninit(&gh);
+ return ret;
+}
+
+static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+ ssize_t ret;
+
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ ret = gfs2_file_direct_read(iocb, to);
+ if (likely(ret != -ENOTBLK))
+ return ret;
+ iocb->ki_flags &= ~IOCB_DIRECT;
+ }
+ return generic_file_read_iter(iocb, to);
+}
+
/**
* gfs2_file_write_iter - Perform a write to a file
* @iocb: The io context
@@ -707,7 +786,7 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct gfs2_inode *ip = GFS2_I(inode);
- ssize_t ret;
+ ssize_t written = 0, ret;
ret = gfs2_rsqa_alloc(ip);
if (ret)
@@ -724,9 +803,6 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
gfs2_glock_dq_uninit(&gh);
}
- if (iocb->ki_flags & IOCB_DIRECT)
- return generic_file_write_iter(iocb, from);
-
inode_lock(inode);
ret = generic_write_checks(iocb, from);
if (ret <= 0)
@@ -743,19 +819,55 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (ret)
goto out2;
- ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ struct address_space *mapping = file->f_mapping;
+ loff_t pos, endbyte;
+ ssize_t buffered;
+
+ written = gfs2_file_direct_write(iocb, from);
+ if (written < 0 || !iov_iter_count(from))
+ goto out2;
+
+ ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
+ if (unlikely(ret < 0))
+ goto out2;
+ buffered = ret;
+
+ /*
+ * We need to ensure that the page cache pages are written to
+ * disk and invalidated to preserve the expected O_DIRECT
+ * semantics.
+ */
+ pos = iocb->ki_pos;
+ endbyte = pos + buffered - 1;
+ ret = filemap_write_and_wait_range(mapping, pos, endbyte);
+ if (!ret) {
+ iocb->ki_pos += buffered;
+ written += buffered;
+ invalidate_mapping_pages(mapping,
+ pos >> PAGE_SHIFT,
+ endbyte >> PAGE_SHIFT);
+ } else {
+ /*
+ * We don't know how much we wrote, so just return
+ * the number of bytes which were direct-written
+ */
+ }
+ } else {
+ ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
+ if (likely(ret > 0))
+ iocb->ki_pos += ret;
+ }
out2:
current->backing_dev_info = NULL;
out:
inode_unlock(inode);
if (likely(ret > 0)) {
- iocb->ki_pos += ret;
-
/* Handle various SYNC-type writes */
ret = generic_write_sync(iocb, ret);
}
- return ret;
+ return written ? written : ret;
}
static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
@@ -1157,7 +1269,7 @@ static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
const struct file_operations gfs2_file_fops = {
.llseek = gfs2_llseek,
- .read_iter = generic_file_read_iter,
+ .read_iter = gfs2_file_read_iter,
.write_iter = gfs2_file_write_iter,
.unlocked_ioctl = gfs2_ioctl,
.mmap = gfs2_mmap,
@@ -1187,7 +1299,7 @@ const struct file_operations gfs2_dir_fops = {
const struct file_operations gfs2_file_fops_nolock = {
.llseek = gfs2_llseek,
- .read_iter = generic_file_read_iter,
+ .read_iter = gfs2_file_read_iter,
.write_iter = gfs2_file_write_iter,
.unlocked_ioctl = gfs2_ioctl,
.mmap = gfs2_mmap,