fuse: invalidate inode mapping if mtime changes (eed2179e) · Commits · 戴 / test

We currently invalidate the inode address space mapping if the file size changes unexpectedly. In the case of a fuse network filesystem, a portion of a file could be overwritten remotely without changing the file size. Compare the old mtime as well to detect this condition and invalidate the mapping if the file has been updated. The original logic (to ignore changes in mtime) is preserved unless the client specifies FUSE_AUTO_INVAL_DATA on init. Signed-off-by:

Brian Foster <bfoster@redhat.com> Signed-off-by:

Miklos Szeredi <mszeredi@suse.cz>

fs/fuse/inode.c

+24 −3

Original line number	Diff line number	Diff line
		@@ -197,6 +197,7 @@ void fuse_change_attributes(struct inode inode, struct fuse_attr attr,
		struct fuse_conn *fc = get_fuse_conn(inode);
		struct fuse_inode *fi = get_fuse_inode(inode);
		loff_t oldsize;
		struct timespec old_mtime;

		spin_lock(&fc->lock);
		if (attr_version != 0 && fi->attr_version > attr_version) {
		@@ -204,14 +205,34 @@ void fuse_change_attributes(struct inode inode, struct fuse_attr attr,
		return;
		}

		old_mtime = inode->i_mtime;
		fuse_change_attributes_common(inode, attr, attr_valid);

		oldsize = inode->i_size;
		i_size_write(inode, attr->size);
		spin_unlock(&fc->lock);

		if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
		if (S_ISREG(inode->i_mode)) {
		bool inval = false;

		if (oldsize != attr->size) {
		truncate_pagecache(inode, oldsize, attr->size);
		inval = true;
		} else if (fc->auto_inval_data) {
		struct timespec new_mtime = {
		.tv_sec = attr->mtime,
		.tv_nsec = attr->mtimensec,
		};

		/*
		* Auto inval mode also checks and invalidates if mtime
		* has changed.
		*/
		if (!timespec_equal(&old_mtime, &new_mtime))
		inval = true;
		}

		if (inval)
		invalidate_inode_pages2(inode->i_mapping);
		}
		}

Admin message