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![Josef Bacik](/assets/img/avatar_default.png)
Btrfs needs to be able to control how filemap_write_and_wait_range() is called in fsync to make it less of a painful operation, so push down taking i_mutex and the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some file systems can drop taking the i_mutex altogether it seems, like ext3 and ocfs2. For correctness sake I just pushed everything down in all cases to make sure that we keep the current behavior the same for everybody, and then each individual fs maintainer can make up their mind about what to do from there. Thanks, Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
240 lines
6.2 KiB
C
240 lines
6.2 KiB
C
/*
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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/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/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 <asm/uaccess.h>
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#include <linux/coda.h>
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#include <linux/coda_psdev.h>
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#include "coda_linux.h"
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#include "coda_int.h"
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static ssize_t
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coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
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{
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struct coda_file_info *cfi;
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struct file *host_file;
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cfi = CODA_FTOC(coda_file);
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BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
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host_file = cfi->cfi_container;
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if (!host_file->f_op || !host_file->f_op->read)
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return -EINVAL;
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return host_file->f_op->read(host_file, buf, count, ppos);
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}
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static ssize_t
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coda_file_splice_read(struct file *coda_file, loff_t *ppos,
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struct pipe_inode_info *pipe, size_t count,
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unsigned int flags)
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{
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ssize_t (*splice_read)(struct file *, loff_t *,
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struct pipe_inode_info *, size_t, unsigned int);
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struct coda_file_info *cfi;
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struct file *host_file;
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cfi = CODA_FTOC(coda_file);
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BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
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host_file = cfi->cfi_container;
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splice_read = host_file->f_op->splice_read;
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if (!splice_read)
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splice_read = default_file_splice_read;
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return splice_read(host_file, ppos, pipe, count, flags);
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}
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static ssize_t
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coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
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{
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struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode;
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struct coda_file_info *cfi;
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struct file *host_file;
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ssize_t ret;
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cfi = CODA_FTOC(coda_file);
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BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
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host_file = cfi->cfi_container;
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if (!host_file->f_op || !host_file->f_op->write)
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return -EINVAL;
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host_inode = host_file->f_path.dentry->d_inode;
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mutex_lock(&coda_inode->i_mutex);
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ret = host_file->f_op->write(host_file, buf, count, ppos);
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coda_inode->i_size = host_inode->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_SEC;
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mutex_unlock(&coda_inode->i_mutex);
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return ret;
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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 coda_file_info *cfi;
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struct coda_inode_info *cii;
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struct file *host_file;
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struct inode *coda_inode, *host_inode;
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cfi = CODA_FTOC(coda_file);
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BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
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host_file = cfi->cfi_container;
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if (!host_file->f_op || !host_file->f_op->mmap)
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return -ENODEV;
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coda_inode = coda_file->f_path.dentry->d_inode;
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host_inode = host_file->f_path.dentry->d_inode;
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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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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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return host_file->f_op->mmap(host_file, vma);
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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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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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int err;
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cfi = CODA_FTOC(coda_file);
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BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
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err = 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 = cfi->cfi_container->f_path.dentry->d_inode;
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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 = coda_file->f_path.dentry->d_inode;
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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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mutex_lock(&coda_inode->i_mutex);
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cfi = CODA_FTOC(coda_file);
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BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
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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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mutex_unlock(&coda_inode->i_mutex);
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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 = coda_file_read,
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.write = coda_file_write,
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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 = coda_file_splice_read,
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};
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