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306 lines
8.0 KiB
306 lines
8.0 KiB
// 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 <[email protected]>. |
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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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