diff options
| -rw-r--r-- | fs/fuse/file.c | 2 | ||||
| -rw-r--r-- | fs/fuse/fuse_i.h | 15 | ||||
| -rw-r--r-- | fs/fuse/readdir.c | 148 |
3 files changed, 161 insertions, 4 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index d15c14912e72..e10c0443c56f 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -59,6 +59,7 @@ struct fuse_file *fuse_file_alloc(struct fuse_conn *fc) } INIT_LIST_HEAD(&ff->write_entry); + mutex_init(&ff->readdir.lock); refcount_set(&ff->count, 1); RB_CLEAR_NODE(&ff->polled_node); init_waitqueue_head(&ff->poll_wait); @@ -73,6 +74,7 @@ struct fuse_file *fuse_file_alloc(struct fuse_conn *fc) void fuse_file_free(struct fuse_file *ff) { fuse_request_free(ff->reserved_req); + mutex_destroy(&ff->readdir.lock); kfree(ff); } diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index d2fa7588533e..49e42635e3ac 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -163,6 +163,21 @@ struct fuse_file { /** Entry on inode's write_files list */ struct list_head write_entry; + /* Readdir related */ + struct { + /* + * Protects below fields against (crazy) parallel readdir on + * same open file. Uncontended in the normal case. + */ + struct mutex lock; + + /* Dir stream position */ + loff_t pos; + + /* Offset in cache */ + loff_t cache_off; + } readdir; + /** RB node to be linked on fuse_conn->polled_files */ struct rb_node polled_node; diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c index 6c5ada164f7e..5bdc0b945d72 100644 --- a/fs/fuse/readdir.c +++ b/fs/fuse/readdir.c @@ -289,7 +289,7 @@ static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file, return 0; } -int fuse_readdir(struct file *file, struct dir_context *ctx) +static int fuse_readdir_uncached(struct file *file, struct dir_context *ctx) { int plus, err; size_t nbytes; @@ -300,9 +300,6 @@ int fuse_readdir(struct file *file, struct dir_context *ctx) u64 attr_version = 0; bool locked; - if (is_bad_inode(inode)) - return -EIO; - req = fuse_get_req(fc, 1); if (IS_ERR(req)) return PTR_ERR(req); @@ -351,3 +348,146 @@ int fuse_readdir(struct file *file, struct dir_context *ctx) fuse_invalidate_atime(inode); return err; } + +enum fuse_parse_result { + FOUND_ERR = -1, + FOUND_NONE = 0, + FOUND_SOME, + FOUND_ALL, +}; + +static enum fuse_parse_result fuse_parse_cache(struct fuse_file *ff, + void *addr, unsigned int size, + struct dir_context *ctx) +{ + unsigned int offset = ff->readdir.cache_off & ~PAGE_MASK; + enum fuse_parse_result res = FOUND_NONE; + + WARN_ON(offset >= size); + + for (;;) { + struct fuse_dirent *dirent = addr + offset; + unsigned int nbytes = size - offset; + size_t reclen = FUSE_DIRENT_SIZE(dirent); + + if (nbytes < FUSE_NAME_OFFSET || !dirent->namelen) + break; + + if (WARN_ON(dirent->namelen > FUSE_NAME_MAX)) + return FOUND_ERR; + if (WARN_ON(reclen > nbytes)) + return FOUND_ERR; + if (WARN_ON(memchr(dirent->name, '/', dirent->namelen) != NULL)) + return FOUND_ERR; + + if (ff->readdir.pos == ctx->pos) { + res = FOUND_SOME; + if (!dir_emit(ctx, dirent->name, dirent->namelen, + dirent->ino, dirent->type)) + return FOUND_ALL; + ctx->pos = dirent->off; + } + ff->readdir.pos = dirent->off; + ff->readdir.cache_off += reclen; + + offset += reclen; + } + + return res; +} + +#define UNCACHED 1 + +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_inode *fi = get_fuse_inode(inode); + enum fuse_parse_result res; + pgoff_t index; + unsigned int size; + struct page *page; + void *addr; + + /* Seeked? If so, reset the cache stream */ + if (ff->readdir.pos != ctx->pos) { + ff->readdir.pos = 0; + ff->readdir.cache_off = 0; + } + +retry: + spin_lock(&fi->rdc.lock); + if (!fi->rdc.cached) { + spin_unlock(&fi->rdc.lock); + return UNCACHED; + } + WARN_ON(fi->rdc.size < ff->readdir.cache_off); + + index = ff->readdir.cache_off >> PAGE_SHIFT; + + if (index == (fi->rdc.size >> PAGE_SHIFT)) + size = fi->rdc.size & ~PAGE_MASK; + else + size = PAGE_SIZE; + spin_unlock(&fi->rdc.lock); + + /* EOF? */ + if ((ff->readdir.cache_off & ~PAGE_MASK) == size) + return 0; + + page = find_get_page_flags(file->f_mapping, index, + FGP_ACCESSED | FGP_LOCK); + if (!page) { + /* + * Uh-oh: page gone missing, cache is useless + */ + return UNCACHED; + } + + addr = kmap(page); + res = fuse_parse_cache(ff, addr, size, ctx); + kunmap(page); + unlock_page(page); + put_page(page); + + if (res == FOUND_ERR) + return -EIO; + + if (res == FOUND_ALL) + return 0; + + if (size == PAGE_SIZE) { + /* We hit end of page: skip to next page. */ + ff->readdir.cache_off = ALIGN(ff->readdir.cache_off, PAGE_SIZE); + goto retry; + } + + /* + * End of cache reached. If found position, then we are done, otherwise + * need to fall back to uncached, since the position we were looking for + * wasn't in the cache. + */ + return res == FOUND_SOME ? 0 : UNCACHED; +} + +int fuse_readdir(struct file *file, struct dir_context *ctx) +{ + struct fuse_file *ff = file->private_data; + struct inode *inode = file_inode(file); + int err; + + if (is_bad_inode(inode)) + return -EIO; + + mutex_lock(&ff->readdir.lock); + + err = UNCACHED; + if (ff->open_flags & FOPEN_CACHE_DIR) + err = fuse_readdir_cached(file, ctx); + if (err == UNCACHED) + err = fuse_readdir_uncached(file, ctx); + + mutex_unlock(&ff->readdir.lock); + + return err; +} |