fuse: update file size on short read

[safe/jmp/linux-2.6] / fs / fuse / file.c

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index c5b5982..a02418c 100644 (file)
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -363,7 +363,7 @@ static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 void fuse_read_fill(struct fuse_req *req, struct file *file,
                    struct inode *inode, loff_t pos, size_t count, int opcode)
 {
-       struct fuse_read_in *inarg = &req->misc.read_in;
+       struct fuse_read_in *inarg = &req->misc.read.in;
        struct fuse_file *ff = file->private_data;
 
        inarg->fh = ff->fh;
@@ -389,7 +389,7 @@ static size_t fuse_send_read(struct fuse_req *req, struct file *file,
 
        fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
        if (owner != NULL) {
-               struct fuse_read_in *inarg = &req->misc.read_in;
+               struct fuse_read_in *inarg = &req->misc.read.in;
 
                inarg->read_flags |= FUSE_READ_LOCKOWNER;
                inarg->lock_owner = fuse_lock_owner_id(fc, owner);
@@ -398,11 +398,29 @@ static size_t fuse_send_read(struct fuse_req *req, struct file *file,
        return req->out.args[0].size;
 }
 
+static void fuse_read_update_size(struct inode *inode, loff_t size,
+                                 u64 attr_ver)
+{
+       struct fuse_conn *fc = get_fuse_conn(inode);
+       struct fuse_inode *fi = get_fuse_inode(inode);
+
+       spin_lock(&fc->lock);
+       if (attr_ver == fi->attr_version && size < inode->i_size) {
+               fi->attr_version = ++fc->attr_version;
+               i_size_write(inode, size);
+       }
+       spin_unlock(&fc->lock);
+}
+
 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;
+       size_t num_read;
+       loff_t pos = page_offset(page);
+       size_t count = PAGE_CACHE_SIZE;
+       u64 attr_ver;
        int err;
 
        err = -EIO;
@@ -421,15 +439,25 @@ static int fuse_readpage(struct file *file, struct page *page)
        if (IS_ERR(req))
                goto out;
 
+       attr_ver = fuse_get_attr_version(fc);
+
        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,
-                      NULL);
+       num_read = fuse_send_read(req, file, inode, pos, count, NULL);
        err = req->out.h.error;
        fuse_put_request(fc, req);
-       if (!err)
+
+       if (!err) {
+               /*
+                * Short read means EOF.  If file size is larger, truncate it
+                */
+               if (num_read < count)
+                       fuse_read_update_size(inode, pos + num_read, attr_ver);
+
                SetPageUptodate(page);
+       }
+
        fuse_invalidate_attr(inode); /* atime changed */
  out:
        unlock_page(page);
@@ -439,8 +467,19 @@ static int fuse_readpage(struct file *file, struct page *page)
 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 {
        int i;
+       size_t count = req->misc.read.in.size;
+       size_t num_read = req->out.args[0].size;
+       struct inode *inode = req->pages[0]->mapping->host;
 
-       fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */
+       /*
+        * Short read means EOF.  If file size is larger, truncate it
+        */
+       if (!req->out.h.error && num_read < count) {
+               loff_t pos = page_offset(req->pages[0]) + num_read;
+               fuse_read_update_size(inode, pos, req->misc.read.attr_ver);
+       }
+
+       fuse_invalidate_attr(inode); /* atime changed */
 
        for (i = 0; i < req->num_pages; i++) {
                struct page *page = req->pages[i];
@@ -463,6 +502,7 @@ static void fuse_send_readpages(struct fuse_req *req, struct file *file,
        size_t count = req->num_pages << PAGE_CACHE_SHIFT;
        req->out.page_zeroing = 1;
        fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
+       req->misc.read.attr_ver = fuse_get_attr_version(fc);
        if (fc->async_read) {
                struct fuse_file *ff = file->private_data;
                req->ff = fuse_file_get(ff);