1 files changed, 440 insertions, 0 deletions
diff --git a/sys/contrib/openzfs/module/os/linux/zfs/zfs_file_os.c b/sys/contrib/openzfs/module/os/linux/zfs/zfs_file_os.c
new file mode 100644
index 000000000000..99c6ffc95940
--- /dev/null
+++ b/sys/contrib/openzfs/module/os/linux/zfs/zfs_file_os.c
@@ -0,0 +1,440 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+#include <sys/zfs_context.h>
+#include <sys/zfs_file.h>
+#include <sys/stat.h>
+#include <sys/file.h>
+#include <linux/falloc.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#ifdef HAVE_FDTABLE_HEADER
+#include <linux/fdtable.h>
+#endif
+
+/*
+ * Open file
+ *
+ * path - fully qualified path to file
+ * flags - file attributes O_READ / O_WRITE / O_EXCL
+ * fpp - pointer to return file pointer
+ *
+ * Returns 0 on success underlying error on failure.
+ */
+int
+zfs_file_open(const char *path, int flags, int mode, zfs_file_t **fpp)
+{
+	struct file *filp;
+	int saved_umask;
+
+	if (!(flags & O_CREAT) && (flags & O_WRONLY))
+		flags |= O_EXCL;
+
+	if (flags & O_CREAT)
+		saved_umask = xchg(&current->fs->umask, 0);
+
+	filp = filp_open(path, flags, mode);
+
+	if (flags & O_CREAT)
+		(void) xchg(&current->fs->umask, saved_umask);
+
+	if (IS_ERR(filp))
+		return (-PTR_ERR(filp));
+
+	*fpp = filp;
+	return (0);
+}
+
+void
+zfs_file_close(zfs_file_t *fp)
+{
+	filp_close(fp, 0);
+}
+
+static ssize_t
+zfs_file_write_impl(zfs_file_t *fp, const void *buf, size_t count, loff_t *off)
+{
+#if defined(HAVE_KERNEL_WRITE_PPOS)
+	return (kernel_write(fp, buf, count, off));
+#else
+	mm_segment_t saved_fs;
+	ssize_t rc;
+
+	saved_fs = get_fs();
+	set_fs(KERNEL_DS);
+
+	rc = vfs_write(fp, (__force const char __user __user *)buf, count, off);
+
+	set_fs(saved_fs);
+
+	return (rc);
+#endif
+}
+
+/*
+ * Stateful write - use os internal file pointer to determine where to
+ * write and update on successful completion.
+ *
+ * fp -  pointer to file (pipe, socket, etc) to write to
+ * buf - buffer to write
+ * count - # of bytes to write
+ * resid -  pointer to count of unwritten bytes  (if short write)
+ *
+ * Returns 0 on success errno on failure.
+ */
+int
+zfs_file_write(zfs_file_t *fp, const void *buf, size_t count, ssize_t *resid)
+{
+	loff_t off = fp->f_pos;
+	ssize_t rc;
+
+	rc = zfs_file_write_impl(fp, buf, count, &off);
+	if (rc < 0)
+		return (-rc);
+
+	fp->f_pos = off;
+
+	if (resid) {
+		*resid = count - rc;
+	} else if (rc != count) {
+		return (EIO);
+	}
+
+	return (0);
+}
+
+/*
+ * Stateless write - os internal file pointer is not updated.
+ *
+ * fp -  pointer to file (pipe, socket, etc) to write to
+ * buf - buffer to write
+ * count - # of bytes to write
+ * off - file offset to write to (only valid for seekable types)
+ * resid -  pointer to count of unwritten bytes
+ *
+ * Returns 0 on success errno on failure.
+ */
+int
+zfs_file_pwrite(zfs_file_t *fp, const void *buf, size_t count, loff_t off,
+    ssize_t *resid)
+{
+	ssize_t rc;
+
+	rc  = zfs_file_write_impl(fp, buf, count, &off);
+	if (rc < 0)
+		return (-rc);
+
+	if (resid) {
+		*resid = count - rc;
+	} else if (rc != count) {
+		return (EIO);
+	}
+
+	return (0);
+}
+
+static ssize_t
+zfs_file_read_impl(zfs_file_t *fp, void *buf, size_t count, loff_t *off)
+{
+#if defined(HAVE_KERNEL_READ_PPOS)
+	return (kernel_read(fp, buf, count, off));
+#else
+	mm_segment_t saved_fs;
+	ssize_t rc;
+
+	saved_fs = get_fs();
+	set_fs(KERNEL_DS);
+
+	rc = vfs_read(fp, (void __user *)buf, count, off);
+	set_fs(saved_fs);
+
+	return (rc);
+#endif
+}
+
+/*
+ * Stateful read - use os internal file pointer to determine where to
+ * read and update on successful completion.
+ *
+ * fp -  pointer to file (pipe, socket, etc) to read from
+ * buf - buffer to write
+ * count - # of bytes to read
+ * resid -  pointer to count of unread bytes (if short read)
+ *
+ * Returns 0 on success errno on failure.
+ */
+int
+zfs_file_read(zfs_file_t *fp, void *buf, size_t count, ssize_t *resid)
+{
+	loff_t off = fp->f_pos;
+	ssize_t rc;
+
+	rc = zfs_file_read_impl(fp, buf, count, &off);
+	if (rc < 0)
+		return (-rc);
+
+	fp->f_pos = off;
+
+	if (resid) {
+		*resid = count - rc;
+	} else if (rc != count) {
+		return (EIO);
+	}
+
+	return (0);
+}
+
+/*
+ * Stateless read - os internal file pointer is not updated.
+ *
+ * fp -  pointer to file (pipe, socket, etc) to read from
+ * buf - buffer to write
+ * count - # of bytes to write
+ * off - file offset to read from (only valid for seekable types)
+ * resid -  pointer to count of unwritten bytes (if short write)
+ *
+ * Returns 0 on success errno on failure.
+ */
+int
+zfs_file_pread(zfs_file_t *fp, void *buf, size_t count, loff_t off,
+    ssize_t *resid)
+{
+	ssize_t rc;
+
+	rc = zfs_file_read_impl(fp, buf, count, &off);
+	if (rc < 0)
+		return (-rc);
+
+	if (resid) {
+		*resid = count - rc;
+	} else if (rc != count) {
+		return (EIO);
+	}
+
+	return (0);
+}
+
+/*
+ * lseek - set / get file pointer
+ *
+ * fp -  pointer to file (pipe, socket, etc) to read from
+ * offp - value to seek to, returns current value plus passed offset
+ * whence - see man pages for standard lseek whence values
+ *
+ * Returns 0 on success errno on failure (ESPIPE for non seekable types)
+ */
+int
+zfs_file_seek(zfs_file_t *fp, loff_t *offp, int whence)
+{
+	loff_t rc;
+
+	if (*offp < 0 || *offp > MAXOFFSET_T)
+		return (EINVAL);
+
+	rc = vfs_llseek(fp, *offp, whence);
+	if (rc < 0)
+		return (-rc);
+
+	*offp = rc;
+
+	return (0);
+}
+
+/*
+ * Get file attributes
+ *
+ * filp - file pointer
+ * zfattr - pointer to file attr structure
+ *
+ * Currently only used for fetching size and file mode.
+ *
+ * Returns 0 on success or error code of underlying getattr call on failure.
+ */
+int
+zfs_file_getattr(zfs_file_t *filp, zfs_file_attr_t *zfattr)
+{
+	struct kstat stat;
+	int rc;
+
+#if defined(HAVE_4ARGS_VFS_GETATTR)
+	rc = vfs_getattr(&filp->f_path, &stat, STATX_BASIC_STATS,
+	    AT_STATX_SYNC_AS_STAT);
+#elif defined(HAVE_2ARGS_VFS_GETATTR)
+	rc = vfs_getattr(&filp->f_path, &stat);
+#else
+	rc = vfs_getattr(filp->f_path.mnt, filp->f_dentry, &stat);
+#endif
+	if (rc)
+		return (-rc);
+
+	zfattr->zfa_size = stat.size;
+	zfattr->zfa_mode = stat.mode;
+
+	return (0);
+}
+
+/*
+ * Sync file to disk
+ *
+ * filp - file pointer
+ * flags - O_SYNC and or O_DSYNC
+ *
+ * Returns 0 on success or error code of underlying sync call on failure.
+ */
+int
+zfs_file_fsync(zfs_file_t *filp, int flags)
+{
+	int datasync = 0;
+	int error;
+	int fstrans;
+
+	if (flags & O_DSYNC)
+		datasync = 1;
+
+	/*
+	 * May enter XFS which generates a warning when PF_FSTRANS is set.
+	 * To avoid this the flag is cleared over vfs_sync() and then reset.
+	 */
+	fstrans = __spl_pf_fstrans_check();
+	if (fstrans)
+		current->flags &= ~(__SPL_PF_FSTRANS);
+
+	error = -vfs_fsync(filp, datasync);
+
+	if (fstrans)
+		current->flags |= __SPL_PF_FSTRANS;
+
+	return (error);
+}
+
+/*
+ * fallocate - allocate or free space on disk
+ *
+ * fp - file pointer
+ * mode (non-standard options for hole punching etc)
+ * offset - offset to start allocating or freeing from
+ * len - length to free / allocate
+ *
+ * OPTIONAL
+ */
+int
+zfs_file_fallocate(zfs_file_t *fp, int mode, loff_t offset, loff_t len)
+{
+	/*
+	 * May enter XFS which generates a warning when PF_FSTRANS is set.
+	 * To avoid this the flag is cleared over vfs_sync() and then reset.
+	 */
+	int fstrans = __spl_pf_fstrans_check();
+	if (fstrans)
+		current->flags &= ~(__SPL_PF_FSTRANS);
+
+	/*
+	 * When supported by the underlying file system preferentially
+	 * use the fallocate() callback to preallocate the space.
+	 */
+	int error = EOPNOTSUPP;
+	if (fp->f_op->fallocate)
+		error = fp->f_op->fallocate(fp, mode, offset, len);
+
+	if (fstrans)
+		current->flags |= __SPL_PF_FSTRANS;
+
+	return (error);
+}
+
+/*
+ * Request current file pointer offset
+ *
+ * fp - pointer to file
+ *
+ * Returns current file offset.
+ */
+loff_t
+zfs_file_off(zfs_file_t *fp)
+{
+	return (fp->f_pos);
+}
+
+/*
+ * Request file pointer private data
+ *
+ * fp - pointer to file
+ *
+ * Returns pointer to file private data.
+ */
+void *
+zfs_file_private(zfs_file_t *fp)
+{
+	return (fp->private_data);
+}
+
+/*
+ * unlink file
+ *
+ * path - fully qualified file path
+ *
+ * Returns 0 on success.
+ *
+ * OPTIONAL
+ */
+int
+zfs_file_unlink(const char *path)
+{
+	return (EOPNOTSUPP);
+}
+
+/*
+ * Get reference to file pointer
+ *
+ * fd - input file descriptor
+ * fpp - pointer to file pointer
+ *
+ * Returns 0 on success EBADF on failure.
+ */
+int
+zfs_file_get(int fd, zfs_file_t **fpp)
+{
+	zfs_file_t *fp;
+
+	fp = fget(fd);
+	if (fp == NULL)
+		return (EBADF);
+
+	*fpp = fp;
+
+	return (0);
+}
+
+/*
+ * Drop reference to file pointer
+ *
+ * fd - input file descriptor
+ */
+void
+zfs_file_put(int fd)
+{
+	struct file *fp;
+
+	if ((fp = fget(fd)) != NULL) {
+		fput(fp);
+		fput(fp);
+	}
+}