6d34ac199a
Since posix_test_lock(), like fcntl() and ->lock(), indicates absence or presence of a conflict lock by setting fl_type to, respectively, F_UNLCK or something other than F_UNLCK, the return value is no longer needed. Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
574 lines
15 KiB
C
574 lines
15 KiB
C
/*
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* linux/fs/nfs/file.c
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*
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* Copyright (C) 1992 Rick Sladkey
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*
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* Changes Copyright (C) 1994 by Florian La Roche
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* - Do not copy data too often around in the kernel.
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* - In nfs_file_read the return value of kmalloc wasn't checked.
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* - Put in a better version of read look-ahead buffering. Original idea
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* and implementation by Wai S Kok elekokws@ee.nus.sg.
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*
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* Expire cache on write to a file by Wai S Kok (Oct 1994).
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*
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* Total rewrite of read side for new NFS buffer cache.. Linus.
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*
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* nfs regular file handling functions
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*/
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#include <linux/time.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/fcntl.h>
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#include <linux/stat.h>
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#include <linux/nfs_fs.h>
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#include <linux/nfs_mount.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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#include <linux/smp_lock.h>
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#include <linux/aio.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include "delegation.h"
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#include "iostat.h"
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#define NFSDBG_FACILITY NFSDBG_FILE
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static int nfs_file_open(struct inode *, struct file *);
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static int nfs_file_release(struct inode *, struct file *);
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static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
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static int nfs_file_mmap(struct file *, struct vm_area_struct *);
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static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
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struct pipe_inode_info *pipe,
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size_t count, unsigned int flags);
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static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos);
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static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos);
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static int nfs_file_flush(struct file *, fl_owner_t id);
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static int nfs_fsync(struct file *, struct dentry *dentry, int datasync);
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static int nfs_check_flags(int flags);
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static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
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static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
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static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
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const struct file_operations nfs_file_operations = {
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.llseek = nfs_file_llseek,
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.read = do_sync_read,
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.write = do_sync_write,
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.aio_read = nfs_file_read,
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.aio_write = nfs_file_write,
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.mmap = nfs_file_mmap,
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.open = nfs_file_open,
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.flush = nfs_file_flush,
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.release = nfs_file_release,
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.fsync = nfs_fsync,
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.lock = nfs_lock,
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.flock = nfs_flock,
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.splice_read = nfs_file_splice_read,
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.check_flags = nfs_check_flags,
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.setlease = nfs_setlease,
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};
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const struct inode_operations nfs_file_inode_operations = {
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.permission = nfs_permission,
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.getattr = nfs_getattr,
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.setattr = nfs_setattr,
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};
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#ifdef CONFIG_NFS_V3
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const struct inode_operations nfs3_file_inode_operations = {
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.permission = nfs_permission,
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.getattr = nfs_getattr,
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.setattr = nfs_setattr,
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.listxattr = nfs3_listxattr,
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.getxattr = nfs3_getxattr,
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.setxattr = nfs3_setxattr,
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.removexattr = nfs3_removexattr,
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};
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#endif /* CONFIG_NFS_v3 */
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/* Hack for future NFS swap support */
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#ifndef IS_SWAPFILE
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# define IS_SWAPFILE(inode) (0)
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#endif
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static int nfs_check_flags(int flags)
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{
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if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
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return -EINVAL;
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return 0;
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}
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/*
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* Open file
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*/
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static int
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nfs_file_open(struct inode *inode, struct file *filp)
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{
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int res;
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res = nfs_check_flags(filp->f_flags);
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if (res)
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return res;
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nfs_inc_stats(inode, NFSIOS_VFSOPEN);
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lock_kernel();
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res = NFS_PROTO(inode)->file_open(inode, filp);
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unlock_kernel();
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return res;
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}
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static int
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nfs_file_release(struct inode *inode, struct file *filp)
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{
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/* Ensure that dirty pages are flushed out with the right creds */
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if (filp->f_mode & FMODE_WRITE)
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filemap_fdatawrite(filp->f_mapping);
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nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
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return NFS_PROTO(inode)->file_release(inode, filp);
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}
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/**
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* nfs_revalidate_size - Revalidate the file size
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* @inode - pointer to inode struct
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* @file - pointer to struct file
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*
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* Revalidates the file length. This is basically a wrapper around
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* nfs_revalidate_inode() that takes into account the fact that we may
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* have cached writes (in which case we don't care about the server's
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* idea of what the file length is), or O_DIRECT (in which case we
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* shouldn't trust the cache).
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*/
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static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
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{
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struct nfs_server *server = NFS_SERVER(inode);
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struct nfs_inode *nfsi = NFS_I(inode);
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if (server->flags & NFS_MOUNT_NOAC)
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goto force_reval;
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if (filp->f_flags & O_DIRECT)
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goto force_reval;
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if (nfsi->npages != 0)
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return 0;
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if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
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return 0;
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force_reval:
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return __nfs_revalidate_inode(server, inode);
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}
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static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
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{
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/* origin == SEEK_END => we must revalidate the cached file length */
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if (origin == SEEK_END) {
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struct inode *inode = filp->f_mapping->host;
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int retval = nfs_revalidate_file_size(inode, filp);
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if (retval < 0)
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return (loff_t)retval;
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}
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return remote_llseek(filp, offset, origin);
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}
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/*
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* Flush all dirty pages, and check for write errors.
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*
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*/
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static int
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nfs_file_flush(struct file *file, fl_owner_t id)
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{
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struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
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struct inode *inode = file->f_path.dentry->d_inode;
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int status;
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dfprintk(VFS, "nfs: flush(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
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if ((file->f_mode & FMODE_WRITE) == 0)
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return 0;
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nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
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lock_kernel();
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/* Ensure that data+attribute caches are up to date after close() */
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status = nfs_wb_all(inode);
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if (!status) {
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status = ctx->error;
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ctx->error = 0;
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if (!status)
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nfs_revalidate_inode(NFS_SERVER(inode), inode);
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}
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unlock_kernel();
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return status;
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}
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static ssize_t
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nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos)
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{
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struct dentry * dentry = iocb->ki_filp->f_path.dentry;
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struct inode * inode = dentry->d_inode;
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ssize_t result;
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size_t count = iov_length(iov, nr_segs);
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#ifdef CONFIG_NFS_DIRECTIO
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if (iocb->ki_filp->f_flags & O_DIRECT)
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return nfs_file_direct_read(iocb, iov, nr_segs, pos);
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#endif
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dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
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dentry->d_parent->d_name.name, dentry->d_name.name,
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(unsigned long) count, (unsigned long) pos);
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result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
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nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
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if (!result)
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result = generic_file_aio_read(iocb, iov, nr_segs, pos);
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return result;
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}
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static ssize_t
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nfs_file_splice_read(struct file *filp, 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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struct dentry *dentry = filp->f_path.dentry;
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struct inode *inode = dentry->d_inode;
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ssize_t res;
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dfprintk(VFS, "nfs: splice_read(%s/%s, %lu@%Lu)\n",
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dentry->d_parent->d_name.name, dentry->d_name.name,
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(unsigned long) count, (unsigned long long) *ppos);
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res = nfs_revalidate_mapping(inode, filp->f_mapping);
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if (!res)
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res = generic_file_splice_read(filp, ppos, pipe, count, flags);
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return res;
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}
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static int
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nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
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{
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struct dentry *dentry = file->f_path.dentry;
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struct inode *inode = dentry->d_inode;
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int status;
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dfprintk(VFS, "nfs: mmap(%s/%s)\n",
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dentry->d_parent->d_name.name, dentry->d_name.name);
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status = nfs_revalidate_mapping(inode, file->f_mapping);
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if (!status)
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status = generic_file_mmap(file, vma);
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return status;
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}
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/*
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* Flush any dirty pages for this process, and check for write errors.
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* The return status from this call provides a reliable indication of
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* whether any write errors occurred for this process.
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*/
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static int
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nfs_fsync(struct file *file, struct dentry *dentry, int datasync)
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{
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struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
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struct inode *inode = dentry->d_inode;
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int status;
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dfprintk(VFS, "nfs: fsync(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
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nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
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lock_kernel();
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status = nfs_wb_all(inode);
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if (!status) {
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status = ctx->error;
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ctx->error = 0;
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}
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unlock_kernel();
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return status;
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}
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/*
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* This does the "real" work of the write. The generic routine has
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* allocated the page, locked it, done all the page alignment stuff
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* calculations etc. Now we should just copy the data from user
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* space and write it back to the real medium..
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*
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* If the writer ends up delaying the write, the writer needs to
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* increment the page use counts until he is done with the page.
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*/
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static int nfs_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
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{
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return nfs_flush_incompatible(file, page);
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}
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static int nfs_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to)
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{
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long status;
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lock_kernel();
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status = nfs_updatepage(file, page, offset, to-offset);
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unlock_kernel();
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return status;
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}
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static void nfs_invalidate_page(struct page *page, unsigned long offset)
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{
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if (offset != 0)
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return;
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/* Cancel any unstarted writes on this page */
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nfs_wb_page_priority(page->mapping->host, page, FLUSH_INVALIDATE);
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}
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static int nfs_release_page(struct page *page, gfp_t gfp)
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{
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/* If PagePrivate() is set, then the page is not freeable */
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return 0;
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}
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static int nfs_launder_page(struct page *page)
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{
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return nfs_wb_page(page->mapping->host, page);
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}
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const struct address_space_operations nfs_file_aops = {
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.readpage = nfs_readpage,
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.readpages = nfs_readpages,
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.set_page_dirty = nfs_set_page_dirty,
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.writepage = nfs_writepage,
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.writepages = nfs_writepages,
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.prepare_write = nfs_prepare_write,
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.commit_write = nfs_commit_write,
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.invalidatepage = nfs_invalidate_page,
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.releasepage = nfs_release_page,
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#ifdef CONFIG_NFS_DIRECTIO
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.direct_IO = nfs_direct_IO,
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#endif
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.launder_page = nfs_launder_page,
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};
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static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos)
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{
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struct dentry * dentry = iocb->ki_filp->f_path.dentry;
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struct inode * inode = dentry->d_inode;
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ssize_t result;
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size_t count = iov_length(iov, nr_segs);
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#ifdef CONFIG_NFS_DIRECTIO
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if (iocb->ki_filp->f_flags & O_DIRECT)
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return nfs_file_direct_write(iocb, iov, nr_segs, pos);
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#endif
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dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%Ld)\n",
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dentry->d_parent->d_name.name, dentry->d_name.name,
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inode->i_ino, (unsigned long) count, (long long) pos);
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result = -EBUSY;
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if (IS_SWAPFILE(inode))
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goto out_swapfile;
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/*
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* O_APPEND implies that we must revalidate the file length.
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*/
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if (iocb->ki_filp->f_flags & O_APPEND) {
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result = nfs_revalidate_file_size(inode, iocb->ki_filp);
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if (result)
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goto out;
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}
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result = count;
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if (!count)
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goto out;
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nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
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result = generic_file_aio_write(iocb, iov, nr_segs, pos);
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/* Return error values for O_SYNC and IS_SYNC() */
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if (result >= 0 && (IS_SYNC(inode) || (iocb->ki_filp->f_flags & O_SYNC))) {
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int err = nfs_fsync(iocb->ki_filp, dentry, 1);
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if (err < 0)
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result = err;
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}
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out:
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return result;
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out_swapfile:
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printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
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goto out;
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}
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static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
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{
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struct inode *inode = filp->f_mapping->host;
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int status = 0;
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lock_kernel();
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/* Try local locking first */
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posix_test_lock(filp, fl);
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if (fl->fl_type != F_UNLCK) {
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/* found a conflict */
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goto out;
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}
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if (nfs_have_delegation(inode, FMODE_READ))
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goto out_noconflict;
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if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
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goto out_noconflict;
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status = NFS_PROTO(inode)->lock(filp, cmd, fl);
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out:
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unlock_kernel();
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return status;
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out_noconflict:
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fl->fl_type = F_UNLCK;
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goto out;
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}
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static int do_vfs_lock(struct file *file, struct file_lock *fl)
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{
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int res = 0;
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switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
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case FL_POSIX:
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res = posix_lock_file_wait(file, fl);
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break;
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case FL_FLOCK:
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res = flock_lock_file_wait(file, fl);
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break;
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default:
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BUG();
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}
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if (res < 0)
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dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
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" - error %d!\n",
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__FUNCTION__, res);
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return res;
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}
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static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
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{
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struct inode *inode = filp->f_mapping->host;
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int status;
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/*
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* Flush all pending writes before doing anything
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* with locks..
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*/
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nfs_sync_mapping(filp->f_mapping);
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/* NOTE: special case
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* If we're signalled while cleaning up locks on process exit, we
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* still need to complete the unlock.
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*/
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lock_kernel();
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/* Use local locking if mounted with "-onolock" */
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if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
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status = NFS_PROTO(inode)->lock(filp, cmd, fl);
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else
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status = do_vfs_lock(filp, fl);
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unlock_kernel();
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return status;
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}
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static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
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{
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struct inode *inode = filp->f_mapping->host;
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int status;
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/*
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* Flush all pending writes before doing anything
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* with locks..
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*/
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status = nfs_sync_mapping(filp->f_mapping);
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if (status != 0)
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goto out;
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lock_kernel();
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/* Use local locking if mounted with "-onolock" */
|
|
if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)) {
|
|
status = NFS_PROTO(inode)->lock(filp, cmd, fl);
|
|
/* If we were signalled we still need to ensure that
|
|
* we clean up any state on the server. We therefore
|
|
* record the lock call as having succeeded in order to
|
|
* ensure that locks_remove_posix() cleans it out when
|
|
* the process exits.
|
|
*/
|
|
if (status == -EINTR || status == -ERESTARTSYS)
|
|
do_vfs_lock(filp, fl);
|
|
} else
|
|
status = do_vfs_lock(filp, fl);
|
|
unlock_kernel();
|
|
if (status < 0)
|
|
goto out;
|
|
/*
|
|
* Make sure we clear the cache whenever we try to get the lock.
|
|
* This makes locking act as a cache coherency point.
|
|
*/
|
|
nfs_sync_mapping(filp->f_mapping);
|
|
nfs_zap_caches(inode);
|
|
out:
|
|
return status;
|
|
}
|
|
|
|
/*
|
|
* Lock a (portion of) a file
|
|
*/
|
|
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
|
|
{
|
|
struct inode * inode = filp->f_mapping->host;
|
|
|
|
dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
|
|
inode->i_sb->s_id, inode->i_ino,
|
|
fl->fl_type, fl->fl_flags,
|
|
(long long)fl->fl_start, (long long)fl->fl_end);
|
|
nfs_inc_stats(inode, NFSIOS_VFSLOCK);
|
|
|
|
/* No mandatory locks over NFS */
|
|
if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
|
|
fl->fl_type != F_UNLCK)
|
|
return -ENOLCK;
|
|
|
|
if (IS_GETLK(cmd))
|
|
return do_getlk(filp, cmd, fl);
|
|
if (fl->fl_type == F_UNLCK)
|
|
return do_unlk(filp, cmd, fl);
|
|
return do_setlk(filp, cmd, fl);
|
|
}
|
|
|
|
/*
|
|
* Lock a (portion of) a file
|
|
*/
|
|
static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
|
|
{
|
|
dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
|
|
filp->f_path.dentry->d_inode->i_sb->s_id,
|
|
filp->f_path.dentry->d_inode->i_ino,
|
|
fl->fl_type, fl->fl_flags);
|
|
|
|
/*
|
|
* No BSD flocks over NFS allowed.
|
|
* Note: we could try to fake a POSIX lock request here by
|
|
* using ((u32) filp | 0x80000000) or some such as the pid.
|
|
* Not sure whether that would be unique, though, or whether
|
|
* that would break in other places.
|
|
*/
|
|
if (!(fl->fl_flags & FL_FLOCK))
|
|
return -ENOLCK;
|
|
|
|
/* We're simulating flock() locks using posix locks on the server */
|
|
fl->fl_owner = (fl_owner_t)filp;
|
|
fl->fl_start = 0;
|
|
fl->fl_end = OFFSET_MAX;
|
|
|
|
if (fl->fl_type == F_UNLCK)
|
|
return do_unlk(filp, cmd, fl);
|
|
return do_setlk(filp, cmd, fl);
|
|
}
|
|
|
|
static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
|
|
{
|
|
/*
|
|
* There is no protocol support for leases, so we have no way
|
|
* to implement them correctly in the face of opens by other
|
|
* clients.
|
|
*/
|
|
return -EINVAL;
|
|
}
|