# HG changeset patch
# User Maxim Dounin <mdounin@mdounin.ru>
# Date 1592838179 -10800
# Node ID 52b34c3f89b460d29228abc79aa96e39b12101c1
# Parent  0a04e5e4c40b018f3010ee7e947da249bc978baa
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.

diff --git a/src/os/unix/ngx_files.h b/src/os/unix/ngx_files.h
--- a/src/os/unix/ngx_files.h
+++ b/src/os/unix/ngx_files.h
@@ -185,7 +185,10 @@ ngx_int_t ngx_set_file_time(u_char *name
 #define ngx_is_exec(sb)          (((sb)->st_mode & S_IXUSR) == S_IXUSR)
 #define ngx_file_access(sb)      ((sb)->st_mode & 0777)
 #define ngx_file_size(sb)        (sb)->st_size
-#define ngx_file_fs_size(sb)     ngx_max((sb)->st_size, (sb)->st_blocks * 512)
+#define ngx_file_fs_size(sb)                                                 \
+    (((sb)->st_blocks * 512 > (sb)->st_size                                  \
+     && (sb)->st_blocks * 512 < (sb)->st_size + 8 * (sb)->st_blksize)        \
+     ? (sb)->st_blocks * 512 : (sb)->st_size)
 #define ngx_file_mtime(sb)       (sb)->st_mtime
 #define ngx_file_uniq(sb)        (sb)->st_ino