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![Arjan van de Ven](/assets/img/avatar_default.png)
Many struct inode_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
561 lines
15 KiB
C
561 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 <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_sendfile(struct file *, loff_t *, size_t, read_actor_t, void *);
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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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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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.sendfile = nfs_file_sendfile,
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.check_flags = nfs_check_flags,
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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_sendfile(struct file *filp, loff_t *ppos, size_t count,
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read_actor_t actor, void *target)
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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: sendfile(%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_sendfile(filp, ppos, count, actor, target);
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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 file_lock cfl;
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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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if (posix_test_lock(filp, fl, &cfl)) {
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fl->fl_start = cfl.fl_start;
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fl->fl_end = cfl.fl_end;
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fl->fl_type = cfl.fl_type;
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fl->fl_pid = cfl.fl_pid;
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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;
|
|
|
|
lock_kernel();
|
|
/* 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);
|
|
}
|