fuse: use mtime for readdir cache verification (7118883b) · Commits · 戴 / test

fs/fuse/fuse_i.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -117,6 +117,9 @@ struct fuse_inode {
		/* version of the cache */
		u64 version;

		/* modification time of directory when cache was started */
		struct timespec64 mtime;

		/* protects above fields */
		spinlock_t lock;
		} rdc;

fs/fuse/readdir.c

+34 −4

Original line number	Diff line number	Diff line
		@@ -399,8 +399,10 @@ static enum fuse_parse_result fuse_parse_cache(struct fuse_file *ff,
		return res;
		}

		static void fuse_rdc_reset(struct fuse_inode *fi)
		static void fuse_rdc_reset(struct inode *inode)
		{
		struct fuse_inode *fi = get_fuse_inode(inode);

		fi->rdc.cached = false;
		fi->rdc.version++;
		fi->rdc.size = 0;
		@@ -413,6 +415,7 @@ static int fuse_readdir_cached(struct file file, struct dir_context ctx)
		{
		struct fuse_file *ff = file->private_data;
		struct inode *inode = file_inode(file);
		struct fuse_conn *fc = get_fuse_conn(inode);
		struct fuse_inode *fi = get_fuse_inode(inode);
		enum fuse_parse_result res;
		pgoff_t index;
		@@ -426,12 +429,40 @@ static int fuse_readdir_cached(struct file file, struct dir_context ctx)
		ff->readdir.cache_off = 0;
		}

		/*
		* We're just about to start reading into the cache or reading the
		* cache; both cases require an up-to-date mtime value.
		*/
		if (!ctx->pos && fc->auto_inval_data) {
		int err = fuse_update_attributes(inode, file);

		if (err)
		return err;
		}

		retry:
		spin_lock(&fi->rdc.lock);
		retry_locked:
		if (!fi->rdc.cached) {
		/* Starting cache? Set cache mtime. */
		if (!ctx->pos && !fi->rdc.size) {
		fi->rdc.mtime = inode->i_mtime;
		}
		spin_unlock(&fi->rdc.lock);
		return UNCACHED;
		}
		/*
		* When at the beginning of the directory (i.e. just after opendir(3) or
		* rewinddir(3)), then need to check whether directory contents have
		* changed, and reset the cache if so.
		*/
		if (!ctx->pos) {
		if (!timespec64_equal(&fi->rdc.mtime, &inode->i_mtime)) {
		fuse_rdc_reset(inode);
		goto retry_locked;
		}
		}

		/*
		* If cache version changed since the last getdents() call, then reset
		* the cache stream.
		@@ -469,9 +500,8 @@ retry:
		* Uh-oh: page gone missing, cache is useless
		*/
		if (fi->rdc.version == ff->readdir.version)
		fuse_rdc_reset(fi);
		spin_unlock(&fi->rdc.lock);
		return UNCACHED;
		fuse_rdc_reset(inode);
		goto retry_locked;
		}

		/* Make sure it's still the same version after getting the page. */

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