Too large st_blocks values are now ignored (ticket #157). With XFS, using "allocsize=64m" mount option results in large preallocation being reported in the st_blocks as returned by fstat() till the file is closed. This in turn results in incorrect cache size calculations and wrong clearing based on max_size. To avoid too aggressive cache clearing on such volumes, st_blocks values which result in sizes larger than st_size and eight blocks (an arbitrary limit) are no longer trusted, and we use st_size instead. The ngx_de_fs_size() counterpart is intentionally not modified, as it is used on closed files and hence not affected by this problem.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_SHMEM_H_INCLUDED_
#define _NGX_SHMEM_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


typedef struct {
    u_char      *addr;
    size_t       size;
    ngx_str_t    name;
    ngx_log_t   *log;
    ngx_uint_t   exists;   /* unsigned  exists:1;  */
} ngx_shm_t;


ngx_int_t ngx_shm_alloc(ngx_shm_t *shm);
void ngx_shm_free(ngx_shm_t *shm);


#endif /* _NGX_SHMEM_H_INCLUDED_ */