Logo Search packages:      
Sourcecode: fuse version File versions  Download package

file.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2006  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#include "fuse_i.h"

#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/kernel.h>

#ifndef KERNEL_2_6
#define PageUptodate(page) Page_Uptodate(page)
#define clear_page_dirty(page)      ClearPageDirty(page)
#endif
#ifndef KERNEL_2_6_11_PLUS
static inline loff_t page_offset(struct page *page)
{
      return ((loff_t)page->index) << PAGE_CACHE_SHIFT;
}
#endif
static struct file_operations fuse_direct_io_file_operations;

static int fuse_send_open(struct inode *inode, struct file *file, int isdir,
                    struct fuse_open_out *outargp)
{
      struct fuse_conn *fc = get_fuse_conn(inode);
      struct fuse_open_in inarg;
      struct fuse_req *req;
      int err;

      req = fuse_get_request(fc);
      if (!req)
            return -EINTR;

      memset(&inarg, 0, sizeof(inarg));
      inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
      req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
      req->in.h.nodeid = get_node_id(inode);
      req->inode = inode;
      req->in.numargs = 1;
      req->in.args[0].size = sizeof(inarg);
      req->in.args[0].value = &inarg;
      req->out.numargs = 1;
      req->out.args[0].size = sizeof(*outargp);
      req->out.args[0].value = outargp;
      request_send(fc, req);
      err = req->out.h.error;
      fuse_put_request(fc, req);

      return err;
}

struct fuse_file *fuse_file_alloc(void)
{
      struct fuse_file *ff;
      ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
      if (ff) {
            ff->release_req = fuse_request_alloc();
            if (!ff->release_req) {
                  kfree(ff);
                  ff = NULL;
            }
      }
      return ff;
}

void fuse_file_free(struct fuse_file *ff)
{
      fuse_request_free(ff->release_req);
      kfree(ff);
}

void fuse_finish_open(struct inode *inode, struct file *file,
                  struct fuse_file *ff, struct fuse_open_out *outarg)
{
      if (outarg->open_flags & FOPEN_DIRECT_IO)
            file->f_op = &fuse_direct_io_file_operations;
      if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
#ifdef KERNEL_2_6
            invalidate_inode_pages(inode->i_mapping);
#else
            invalidate_inode_pages(inode);
#endif
      ff->fh = outarg->fh;
      file->private_data = ff;
}

int fuse_open_common(struct inode *inode, struct file *file, int isdir)
{
      struct fuse_open_out outarg;
      struct fuse_file *ff;
      int err;

      /* VFS checks this, but only _after_ ->open() */
      if (file->f_flags & O_DIRECT)
            return -EINVAL;

      err = generic_file_open(inode, file);
      if (err)
            return err;

      /* If opening the root node, no lookup has been performed on
         it, so the attributes must be refreshed */
      if (get_node_id(inode) == FUSE_ROOT_ID) {
            err = fuse_do_getattr(inode);
            if (err)
                  return err;
      }

      ff = fuse_file_alloc();
      if (!ff)
            return -ENOMEM;

      err = fuse_send_open(inode, file, isdir, &outarg);
      if (err)
            fuse_file_free(ff);
      else {
            if (isdir)
                  outarg.open_flags &= ~FOPEN_DIRECT_IO;
            fuse_finish_open(inode, file, ff, &outarg);
      }

      return err;
}

void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff,
                   u64 nodeid, struct inode *inode, int flags, int isdir)
{
      struct fuse_req * req = ff->release_req;
      struct fuse_release_in *inarg = &req->misc.release_in;

      inarg->fh = ff->fh;
      inarg->flags = flags;
      req->in.h.opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
      req->in.h.nodeid = nodeid;
      req->inode = inode;
      req->in.numargs = 1;
      req->in.args[0].size = sizeof(struct fuse_release_in);
      req->in.args[0].value = inarg;
      request_send_background(fc, req);
      kfree(ff);
}

int fuse_release_common(struct inode *inode, struct file *file, int isdir)
{
      struct fuse_file *ff = file->private_data;
      if (ff) {
            struct fuse_conn *fc = get_fuse_conn(inode);
            u64 nodeid = get_node_id(inode);
            fuse_send_release(fc, ff, nodeid, inode, file->f_flags, isdir);
      }

      /* Return value is ignored by VFS */
      return 0;
}

static int fuse_open(struct inode *inode, struct file *file)
{
      return fuse_open_common(inode, file, 0);
}

static int fuse_release(struct inode *inode, struct file *file)
{
      return fuse_release_common(inode, file, 0);
}

static int fuse_flush(struct file *file)
{
      struct inode *inode = file->f_dentry->d_inode;
      struct fuse_conn *fc = get_fuse_conn(inode);
      struct fuse_file *ff = file->private_data;
      struct fuse_req *req;
      struct fuse_flush_in inarg;
      int err;

      if (is_bad_inode(inode))
            return -EIO;

      if (fc->no_flush)
            return 0;

      req = fuse_get_request(fc);
      if (!req)
            return -EINTR;

      memset(&inarg, 0, sizeof(inarg));
      inarg.fh = ff->fh;
      req->in.h.opcode = FUSE_FLUSH;
      req->in.h.nodeid = get_node_id(inode);
      req->inode = inode;
      req->file = file;
      req->in.numargs = 1;
      req->in.args[0].size = sizeof(inarg);
      req->in.args[0].value = &inarg;
      request_send(fc, req);
      err = req->out.h.error;
      fuse_put_request(fc, req);
      if (err == -ENOSYS) {
            fc->no_flush = 1;
            err = 0;
      }
      return err;
}

int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
                  int isdir)
{
      struct inode *inode = de->d_inode;
      struct fuse_conn *fc = get_fuse_conn(inode);
      struct fuse_file *ff = file->private_data;
      struct fuse_req *req;
      struct fuse_fsync_in inarg;
      int err;

      if (is_bad_inode(inode))
            return -EIO;

      if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
            return 0;

      req = fuse_get_request(fc);
      if (!req)
            return -EINTR;

      memset(&inarg, 0, sizeof(inarg));
      inarg.fh = ff->fh;
      inarg.fsync_flags = datasync ? 1 : 0;
      req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
      req->in.h.nodeid = get_node_id(inode);
      req->inode = inode;
      req->file = file;
      req->in.numargs = 1;
      req->in.args[0].size = sizeof(inarg);
      req->in.args[0].value = &inarg;
      request_send(fc, req);
      err = req->out.h.error;
      fuse_put_request(fc, req);
      if (err == -ENOSYS) {
            if (isdir)
                  fc->no_fsyncdir = 1;
            else
                  fc->no_fsync = 1;
            err = 0;
      }
      return err;
}

static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
{
      return fuse_fsync_common(file, de, datasync, 0);
}

size_t fuse_send_read_common(struct fuse_req *req, struct file *file,
                       struct inode *inode, loff_t pos, size_t count,
                       int isdir)
{
      struct fuse_conn *fc = get_fuse_conn(inode);
      struct fuse_file *ff = file->private_data;
      struct fuse_read_in inarg;

      memset(&inarg, 0, sizeof(struct fuse_read_in));
      inarg.fh = ff->fh;
      inarg.offset = pos;
      inarg.size = count;
      req->in.h.opcode = isdir ? FUSE_READDIR : FUSE_READ;
      req->in.h.nodeid = get_node_id(inode);
      req->inode = inode;
      req->file = file;
      req->in.numargs = 1;
      req->in.args[0].size = sizeof(struct fuse_read_in);
      req->in.args[0].value = &inarg;
      req->out.argpages = 1;
      req->out.argvar = 1;
      req->out.numargs = 1;
      req->out.args[0].size = count;
      request_send(fc, req);
      return req->out.args[0].size;
}

static inline size_t fuse_send_read(struct fuse_req *req, struct file *file,
                            struct inode *inode, loff_t pos,
                            size_t count)
{
      return fuse_send_read_common(req, file, inode, pos, count, 0);
}

static int fuse_readpage(struct file *file, struct page *page)
{
      struct inode *inode = page->mapping->host;
      struct fuse_conn *fc = get_fuse_conn(inode);
      struct fuse_req *req;
      int err;

      err = -EIO;
      if (is_bad_inode(inode))
            goto out;

      err = -EINTR;
      req = fuse_get_request(fc);
      if (!req)
            goto out;

      req->out.page_zeroing = 1;
      req->num_pages = 1;
      req->pages[0] = page;
      fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE);
      err = req->out.h.error;
      fuse_put_request(fc, req);
      if (!err)
            SetPageUptodate(page);
      fuse_invalidate_attr(inode); /* atime changed */
 out:
      unlock_page(page);
      return err;
}

#ifdef KERNEL_2_6
static int fuse_send_readpages(struct fuse_req *req, struct file *file,
                         struct inode *inode)
{
      loff_t pos = page_offset(req->pages[0]);
      size_t count = req->num_pages << PAGE_CACHE_SHIFT;
      unsigned i;
      req->out.page_zeroing = 1;
      fuse_send_read(req, file, inode, pos, count);
      for (i = 0; i < req->num_pages; i++) {
            struct page *page = req->pages[i];
            if (!req->out.h.error)
                  SetPageUptodate(page);
            unlock_page(page);
      }
      return req->out.h.error;
}

struct fuse_readpages_data {
      struct fuse_req *req;
      struct file *file;
      struct inode *inode;
};

static int fuse_readpages_fill(void *_data, struct page *page)
{
      struct fuse_readpages_data *data = _data;
      struct fuse_req *req = data->req;
      struct inode *inode = data->inode;
      struct fuse_conn *fc = get_fuse_conn(inode);

      if (req->num_pages &&
          (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
           (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
           req->pages[req->num_pages - 1]->index + 1 != page->index)) {
            int err = fuse_send_readpages(req, data->file, inode);
            if (err) {
                  unlock_page(page);
                  return err;
            }
            fuse_reset_request(req);
      }
      req->pages[req->num_pages] = page;
      req->num_pages ++;
      return 0;
}

static int fuse_readpages(struct file *file, struct address_space *mapping,
                    struct list_head *pages, unsigned nr_pages)
{
      struct inode *inode = mapping->host;
      struct fuse_conn *fc = get_fuse_conn(inode);
      struct fuse_readpages_data data;
      int err;

      if (is_bad_inode(inode))
            return -EIO;

      data.file = file;
      data.inode = inode;
      data.req = fuse_get_request(fc);
      if (!data.req)
            return -EINTR;

      err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
      if (!err && data.req->num_pages)
            err = fuse_send_readpages(data.req, file, inode);
      fuse_put_request(fc, data.req);
      fuse_invalidate_attr(inode); /* atime changed */
      return err;
}
#else /* KERNEL_2_6 */
#define FUSE_BLOCK_SHIFT 16
#define FUSE_BLOCK_SIZE (1UL << FUSE_BLOCK_SHIFT)
#define FUSE_BLOCK_MASK (~(FUSE_BLOCK_SIZE-1))
#if (1UL << (FUSE_BLOCK_SHIFT - PAGE_CACHE_SHIFT)) > FUSE_MAX_PAGES_PER_REQ
#error FUSE_BLOCK_SHIFT too large
#endif

static int fuse_is_block_uptodate(struct inode *inode, unsigned start,
                          unsigned end)
{
      int index;

      for (index = start; index < end; index++) {
            struct page *page = find_get_page(inode->i_mapping, index);
            if (!page)
                  return 0;
            if (!PageUptodate(page)) {
                  page_cache_release(page);
                  return 0;
            }
            page_cache_release(page);
      }
      return 1;
}

static int fuse_file_read_block(struct fuse_req *req, struct file *file,
                        struct inode *inode, unsigned start,
                        unsigned end)
{
      loff_t pos;
      size_t count;
      int index;
      int err = -EBUSY;
      int i;

      for (index = start; index < end; index++) {
            struct page *page = grab_cache_page(inode->i_mapping, index);
            if (!page)
                  goto out;
            if (PageUptodate(page)) {
                  unlock_page(page);
                  page_cache_release(page);
                  page = NULL;
            }
            req->pages[req->num_pages++] = page;
      }
      pos = (loff_t) start << PAGE_CACHE_SHIFT;
      count = req->num_pages << PAGE_CACHE_SHIFT;
      fuse_send_read(req, file, inode, pos, count);
      err = req->out.h.error;
 out:
      for (i = 0; i < req->num_pages; i++) {
            struct page *page = req->pages[i];
            if (page) {
                  if (!err)
                        SetPageUptodate(page);
                  unlock_page(page);
                  page_cache_release(page);
            }
      }
      return err;
}

static int fuse_file_bigread(struct file *file, struct inode *inode,
                       loff_t pos, size_t count)
{
      struct fuse_conn *fc = get_fuse_conn(inode);
      unsigned starti;
      unsigned endi;
      unsigned nexti;
      struct fuse_req *req;
      loff_t size = i_size_read(inode);
      loff_t end = (pos + count + FUSE_BLOCK_SIZE - 1) & FUSE_BLOCK_MASK;
      end = min(end, size);
      if (end <= pos)
            return 0;

      starti = (pos & FUSE_BLOCK_MASK) >> PAGE_CACHE_SHIFT;
      endi = (end + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;

      req = fuse_get_request(fc);
      if (!req)
            return -EINTR;

      for (; starti < endi; starti = nexti) {
            nexti = starti + (FUSE_BLOCK_SIZE >> PAGE_CACHE_SHIFT);
            nexti = min(nexti, endi);
            if (!fuse_is_block_uptodate(inode, starti, nexti)) {
                  if (fuse_file_read_block(req, file, inode, starti, nexti))
                        break;

                  fuse_reset_request(req);
            }
      }
      fuse_put_request(fc, req);
      return 0;
}
#endif /* KERNEL_2_6 */

static size_t fuse_send_write(struct fuse_req *req, struct file *file,
                        struct inode *inode, loff_t pos, size_t count)
{
      struct fuse_conn *fc = get_fuse_conn(inode);
      struct fuse_file *ff = file->private_data;
      struct fuse_write_in inarg;
      struct fuse_write_out outarg;

      memset(&inarg, 0, sizeof(struct fuse_write_in));
      inarg.fh = ff->fh;
      inarg.offset = pos;
      inarg.size = count;
      req->in.h.opcode = FUSE_WRITE;
      req->in.h.nodeid = get_node_id(inode);
      req->inode = inode;
      req->file = file;
      req->in.argpages = 1;
      req->in.numargs = 2;
      req->in.args[0].size = sizeof(struct fuse_write_in);
      req->in.args[0].value = &inarg;
      req->in.args[1].size = count;
      req->out.numargs = 1;
      req->out.args[0].size = sizeof(struct fuse_write_out);
      req->out.args[0].value = &outarg;
      request_send(fc, req);
      return outarg.size;
}

static int fuse_prepare_write(struct file *file, struct page *page,
                        unsigned offset, unsigned to)
{
      /* No op */
      return 0;
}

static int fuse_commit_write(struct file *file, struct page *page,
                       unsigned offset, unsigned to)
{
      int err;
      size_t nres;
      unsigned count = to - offset;
      struct inode *inode = page->mapping->host;
      struct fuse_conn *fc = get_fuse_conn(inode);
      loff_t pos = page_offset(page) + offset;
      struct fuse_req *req;

      if (is_bad_inode(inode))
            return -EIO;

      req = fuse_get_request(fc);
      if (!req)
            return -EINTR;

      req->num_pages = 1;
      req->pages[0] = page;
      req->page_offset = offset;
      nres = fuse_send_write(req, file, inode, pos, count);
      err = req->out.h.error;
      fuse_put_request(fc, req);
      if (!err && nres != count)
            err = -EIO;
      if (!err) {
            pos += count;
            if (pos > i_size_read(inode))
                  i_size_write(inode, pos);

            if (offset == 0 && to == PAGE_CACHE_SIZE) {
                  clear_page_dirty(page);
                  SetPageUptodate(page);
            }
      }
      fuse_invalidate_attr(inode);
      return err;
}

static void fuse_release_user_pages(struct fuse_req *req, int write)
{
      unsigned i;

      for (i = 0; i < req->num_pages; i++) {
            struct page *page = req->pages[i];
            if (write)
                  set_page_dirty_lock(page);
            put_page(page);
      }
}

static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
                         unsigned nbytes, int write)
{
      unsigned long user_addr = (unsigned long) buf;
      unsigned offset = user_addr & ~PAGE_MASK;
      int npages;

      /* This doesn't work with nfsd */
      if (!current->mm)
            return -EPERM;

      nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
      npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
      npages = max(npages, 1);
      npages = min(npages, FUSE_MAX_PAGES_PER_REQ);
      down_read(&current->mm->mmap_sem);
      npages = get_user_pages(current, current->mm, user_addr, npages, write,
                        0, req->pages, NULL);
      up_read(&current->mm->mmap_sem);
      if (npages < 0)
            return npages;

      req->num_pages = npages;
      req->page_offset = offset;
      return 0;
}

static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
                        size_t count, loff_t *ppos, int write)
{
      struct inode *inode = file->f_dentry->d_inode;
      struct fuse_conn *fc = get_fuse_conn(inode);
      size_t nmax = write ? fc->max_write : fc->max_read;
      loff_t pos = *ppos;
      ssize_t res = 0;
      struct fuse_req *req;

      if (is_bad_inode(inode))
            return -EIO;

      req = fuse_get_request(fc);
      if (!req)
            return -EINTR;

      while (count) {
            size_t nres;
            size_t nbytes = min(count, nmax);
            int err = fuse_get_user_pages(req, buf, nbytes, !write);
            if (err) {
                  res = err;
                  break;
            }
            nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
            nbytes = min(count, nbytes);
            if (write)
                  nres = fuse_send_write(req, file, inode, pos, nbytes);
            else
                  nres = fuse_send_read(req, file, inode, pos, nbytes);
            fuse_release_user_pages(req, !write);
            if (req->out.h.error) {
                  if (!res)
                        res = req->out.h.error;
                  break;
            } else if (nres > nbytes) {
                  res = -EIO;
                  break;
            }
            count -= nres;
            res += nres;
            pos += nres;
            buf += nres;
            if (nres != nbytes)
                  break;
            if (count)
                  fuse_reset_request(req);
      }
      fuse_put_request(fc, req);
      if (res > 0) {
            if (write && pos > i_size_read(inode))
                  i_size_write(inode, pos);
            *ppos = pos;
      }
      fuse_invalidate_attr(inode);

      return res;
}

static ssize_t fuse_direct_read(struct file *file, char __user *buf,
                             size_t count, loff_t *ppos)
{
      return fuse_direct_io(file, buf, count, ppos, 0);
}

static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
                         size_t count, loff_t *ppos)
{
      struct inode *inode = file->f_dentry->d_inode;
      ssize_t res;
      /* Don't allow parallel writes to the same file */
#ifdef KERNEL_2_6_16_PLUS
      mutex_lock(&inode->i_mutex);
      res = fuse_direct_io(file, buf, count, ppos, 1);
      mutex_unlock(&inode->i_mutex);
#else
      down(&inode->i_sem);
      res = fuse_direct_io(file, buf, count, ppos, 1);
      up(&inode->i_sem);
#endif
      return res;
}

#ifndef KERNEL_2_6
static ssize_t fuse_file_read(struct file *file, char __user *buf,
                        size_t count, loff_t *ppos)
{
      struct inode *inode = file->f_dentry->d_inode;
      struct fuse_conn *fc = get_fuse_conn(inode);

      if (is_bad_inode(inode))
            return -EIO;

      if (fc->flags & FUSE_LARGE_READ) {
            int res;
            down(&inode->i_sem);
            res = fuse_file_bigread(file, inode, *ppos, count);
            up(&inode->i_sem);
            if (res)
                  return res;
      }
      return generic_file_read(file, buf, count, ppos);
}
#endif
static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
{
      if ((vma->vm_flags & VM_SHARED)) {
            if ((vma->vm_flags & VM_WRITE))
                  return -ENODEV;
            else
                  vma->vm_flags &= ~VM_MAYWRITE;
      }
      return generic_file_mmap(file, vma);
}

#ifdef KERNEL_2_6
static int fuse_set_page_dirty(struct page *page)
{
      printk("fuse_set_page_dirty: should not happen\n");
      dump_stack();
      return 0;
}
#endif

static struct file_operations fuse_file_operations = {
      .llseek           = generic_file_llseek,
#ifdef KERNEL_2_6
      .read       = do_sync_read,
      .write            = do_sync_write,
      .readv            = generic_file_readv,
      .writev           = generic_file_writev,
      .aio_read   = generic_file_aio_read,
      .aio_write  = generic_file_aio_write,
#else
      .read       = fuse_file_read,
      .write            = generic_file_write,
#endif
      .mmap       = fuse_file_mmap,
      .open       = fuse_open,
      .flush            = fuse_flush,
      .release    = fuse_release,
      .fsync            = fuse_fsync,
#ifdef KERNEL_2_6
      .sendfile   = generic_file_sendfile,
#endif
};

static struct file_operations fuse_direct_io_file_operations = {
      .llseek           = generic_file_llseek,
      .read       = fuse_direct_read,
      .write            = fuse_direct_write,
      .open       = fuse_open,
      .flush            = fuse_flush,
      .release    = fuse_release,
      .fsync            = fuse_fsync,
      /* no mmap and sendfile */
};

static struct address_space_operations fuse_file_aops  = {
      .readpage   = fuse_readpage,
      .prepare_write    = fuse_prepare_write,
      .commit_write     = fuse_commit_write,
#ifdef KERNEL_2_6
      .readpages  = fuse_readpages,
      .set_page_dirty   = fuse_set_page_dirty,
#endif
};

void fuse_init_file_inode(struct inode *inode)
{
      inode->i_fop = &fuse_file_operations;
      inode->i_data.a_ops = &fuse_file_aops;
}

Generated by  Doxygen 1.6.0   Back to index