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![Matthew Wilcox (Oracle)](/assets/img/avatar_default.png)
These functions are page cache functionality and don't need to be declared in fs.h. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
306 lines
8 KiB
C
306 lines
8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* File operations for Coda.
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* Original version: (C) 1996 Peter Braam
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* Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
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*
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* Carnegie Mellon encourages users of this code to contribute improvements
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* to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
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*/
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#include <linux/refcount.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/time.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/stat.h>
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#include <linux/cred.h>
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#include <linux/errno.h>
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#include <linux/spinlock.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/uio.h>
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#include <linux/coda.h>
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#include "coda_psdev.h"
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#include "coda_linux.h"
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#include "coda_int.h"
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struct coda_vm_ops {
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refcount_t refcnt;
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struct file *coda_file;
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const struct vm_operations_struct *host_vm_ops;
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struct vm_operations_struct vm_ops;
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};
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static ssize_t
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coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
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{
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struct file *coda_file = iocb->ki_filp;
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struct inode *coda_inode = file_inode(coda_file);
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struct coda_file_info *cfi = coda_ftoc(coda_file);
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loff_t ki_pos = iocb->ki_pos;
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size_t count = iov_iter_count(to);
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ssize_t ret;
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ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
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&cfi->cfi_access_intent,
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count, ki_pos, CODA_ACCESS_TYPE_READ);
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if (ret)
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goto finish_read;
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ret = vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0);
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finish_read:
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venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
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&cfi->cfi_access_intent,
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count, ki_pos, CODA_ACCESS_TYPE_READ_FINISH);
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return ret;
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}
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static ssize_t
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coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to)
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{
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struct file *coda_file = iocb->ki_filp;
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struct inode *coda_inode = file_inode(coda_file);
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struct coda_file_info *cfi = coda_ftoc(coda_file);
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struct file *host_file = cfi->cfi_container;
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loff_t ki_pos = iocb->ki_pos;
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size_t count = iov_iter_count(to);
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ssize_t ret;
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ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
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&cfi->cfi_access_intent,
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count, ki_pos, CODA_ACCESS_TYPE_WRITE);
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if (ret)
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goto finish_write;
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file_start_write(host_file);
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inode_lock(coda_inode);
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ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
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coda_inode->i_size = file_inode(host_file)->i_size;
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coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
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coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode);
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inode_unlock(coda_inode);
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file_end_write(host_file);
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finish_write:
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venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
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&cfi->cfi_access_intent,
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count, ki_pos, CODA_ACCESS_TYPE_WRITE_FINISH);
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return ret;
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}
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static void
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coda_vm_open(struct vm_area_struct *vma)
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{
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struct coda_vm_ops *cvm_ops =
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container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
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refcount_inc(&cvm_ops->refcnt);
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if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open)
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cvm_ops->host_vm_ops->open(vma);
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}
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static void
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coda_vm_close(struct vm_area_struct *vma)
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{
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struct coda_vm_ops *cvm_ops =
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container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
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if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close)
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cvm_ops->host_vm_ops->close(vma);
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if (refcount_dec_and_test(&cvm_ops->refcnt)) {
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vma->vm_ops = cvm_ops->host_vm_ops;
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fput(cvm_ops->coda_file);
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kfree(cvm_ops);
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}
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}
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static int
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coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
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{
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struct inode *coda_inode = file_inode(coda_file);
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struct coda_file_info *cfi = coda_ftoc(coda_file);
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struct file *host_file = cfi->cfi_container;
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struct inode *host_inode = file_inode(host_file);
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struct coda_inode_info *cii;
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struct coda_vm_ops *cvm_ops;
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loff_t ppos;
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size_t count;
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int ret;
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if (!host_file->f_op->mmap)
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return -ENODEV;
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if (WARN_ON(coda_file != vma->vm_file))
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return -EIO;
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count = vma->vm_end - vma->vm_start;
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ppos = vma->vm_pgoff * PAGE_SIZE;
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ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
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&cfi->cfi_access_intent,
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count, ppos, CODA_ACCESS_TYPE_MMAP);
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if (ret)
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return ret;
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cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL);
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if (!cvm_ops)
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return -ENOMEM;
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cii = ITOC(coda_inode);
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spin_lock(&cii->c_lock);
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coda_file->f_mapping = host_file->f_mapping;
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if (coda_inode->i_mapping == &coda_inode->i_data)
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coda_inode->i_mapping = host_inode->i_mapping;
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/* only allow additional mmaps as long as userspace isn't changing
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* the container file on us! */
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else if (coda_inode->i_mapping != host_inode->i_mapping) {
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spin_unlock(&cii->c_lock);
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kfree(cvm_ops);
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return -EBUSY;
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}
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/* keep track of how often the coda_inode/host_file has been mmapped */
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cii->c_mapcount++;
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cfi->cfi_mapcount++;
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spin_unlock(&cii->c_lock);
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vma->vm_file = get_file(host_file);
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ret = call_mmap(vma->vm_file, vma);
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if (ret) {
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/* if call_mmap fails, our caller will put host_file so we
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* should drop the reference to the coda_file that we got.
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*/
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fput(coda_file);
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kfree(cvm_ops);
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} else {
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/* here we add redirects for the open/close vm_operations */
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cvm_ops->host_vm_ops = vma->vm_ops;
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if (vma->vm_ops)
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cvm_ops->vm_ops = *vma->vm_ops;
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cvm_ops->vm_ops.open = coda_vm_open;
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cvm_ops->vm_ops.close = coda_vm_close;
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cvm_ops->coda_file = coda_file;
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refcount_set(&cvm_ops->refcnt, 1);
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vma->vm_ops = &cvm_ops->vm_ops;
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}
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return ret;
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}
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int coda_open(struct inode *coda_inode, struct file *coda_file)
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{
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struct file *host_file = NULL;
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int error;
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unsigned short flags = coda_file->f_flags & (~O_EXCL);
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unsigned short coda_flags = coda_flags_to_cflags(flags);
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struct coda_file_info *cfi;
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cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
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if (!cfi)
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return -ENOMEM;
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error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
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&host_file);
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if (!host_file)
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error = -EIO;
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if (error) {
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kfree(cfi);
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return error;
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}
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host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
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cfi->cfi_magic = CODA_MAGIC;
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cfi->cfi_mapcount = 0;
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cfi->cfi_container = host_file;
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/* assume access intents are supported unless we hear otherwise */
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cfi->cfi_access_intent = true;
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BUG_ON(coda_file->private_data != NULL);
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coda_file->private_data = cfi;
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return 0;
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}
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int coda_release(struct inode *coda_inode, struct file *coda_file)
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{
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unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
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unsigned short coda_flags = coda_flags_to_cflags(flags);
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struct coda_file_info *cfi;
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struct coda_inode_info *cii;
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struct inode *host_inode;
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cfi = coda_ftoc(coda_file);
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venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
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coda_flags, coda_file->f_cred->fsuid);
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host_inode = file_inode(cfi->cfi_container);
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cii = ITOC(coda_inode);
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/* did we mmap this file? */
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spin_lock(&cii->c_lock);
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if (coda_inode->i_mapping == &host_inode->i_data) {
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cii->c_mapcount -= cfi->cfi_mapcount;
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if (!cii->c_mapcount)
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coda_inode->i_mapping = &coda_inode->i_data;
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}
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spin_unlock(&cii->c_lock);
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fput(cfi->cfi_container);
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kfree(coda_file->private_data);
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coda_file->private_data = NULL;
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/* VFS fput ignores the return value from file_operations->release, so
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* there is no use returning an error here */
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return 0;
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}
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int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
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{
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struct file *host_file;
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struct inode *coda_inode = file_inode(coda_file);
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struct coda_file_info *cfi;
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int err;
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if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
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S_ISLNK(coda_inode->i_mode)))
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return -EINVAL;
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err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
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if (err)
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return err;
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inode_lock(coda_inode);
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cfi = coda_ftoc(coda_file);
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host_file = cfi->cfi_container;
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err = vfs_fsync(host_file, datasync);
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if (!err && !datasync)
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err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
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inode_unlock(coda_inode);
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return err;
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}
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const struct file_operations coda_file_operations = {
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.llseek = generic_file_llseek,
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.read_iter = coda_file_read_iter,
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.write_iter = coda_file_write_iter,
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.mmap = coda_file_mmap,
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.open = coda_open,
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.release = coda_release,
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.fsync = coda_fsync,
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.splice_read = generic_file_splice_read,
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};
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