The call to posix_fadvise(POSIX_FADV_WILLNEED) should have the same
effect as the call to readahead() syscall.
Repeat the test cases for local file and overlayfs file with
posix_fadvise().
The new test case is a regression test for kernel commit b833a3660394
("ovl: add ovl_fadvise()") which fixes a regression of fadvise() on
an overlay file that was introduced by kernel commit 5b910bd615ba
("ovl: fix GPF in swapfile_activate of file from overlayfs over xfs").
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
.../kernel/syscalls/readahead/readahead02.c | 57 +++++++++++++++++--
1 file changed, 51 insertions(+), 6 deletions(-)
diff --git a/testcases/kernel/syscalls/readahead/readahead02.c b/testcases/kernel/syscalls/readahead/readahead02.c
index 191116f62..9ebed359d 100644
--- a/testcases/kernel/syscalls/readahead/readahead02.c
+++ b/testcases/kernel/syscalls/readahead/readahead02.c
@@ -51,6 +51,42 @@ static struct tst_option options[] = {
{NULL, NULL, NULL}
};
+#ifndef _FILE_OFFSET_BITS
+#define _FILE_OFFSET_BITS 32
+#endif
+
+#ifndef __NR_fadvise64
+#define __NR_fadvise64 0
+#endif
+
+static struct tcase {
+ const char *tname;
+ int use_overlay;
+ int use_fadvise;
+} tcases[] = {
+ { "readahead on file", 0, 0 },
+ { "readahead on overlayfs file", 1, 0 },
+/* Check this system has fadvise64 system which is used in posix_fadvise. */
+#if ((_FILE_OFFSET_BITS == 64) || (__NR_fadvise64 != 0))
+ { "POSIX_FADV_WILLNEED on file", 0, 1 },
+ { "POSIX_FADV_WILLNEED on overlayfs file", 1, 1 },
+#endif
+};
+
+static int fadvise_willneed(int fd, off_t offset, size_t len)
+{
+ /* Should have the same effect as readahead() syscall */
+ return posix_fadvise(fd, offset, len, POSIX_FADV_WILLNEED);
+}
+
+static int libc_readahead(int fd, off_t offset, size_t len)
+{
+ return readahead(fd, offset, len);
+}
+
+typedef int (*readahead_func_t)(int, off_t, size_t);
+static readahead_func_t readahead_func = libc_readahead;
+
static int check_ret(long expected_ret)
{
if (expected_ret == TST_RET) {
@@ -120,6 +156,9 @@ static int setup_overlay(void)
{
int ret;
+ if (ovl_mounted)
+ return 0;
+
/* Setup an overlay mount with lower dir and file */
SAFE_MKDIR(OVL_LOWER, 0755);
SAFE_MKDIR(OVL_UPPER, 0755);
@@ -139,7 +178,7 @@ static int setup_overlay(void)
return 0;
}
-static int create_testfile(unsigned int use_overlay)
+static int create_testfile(int use_overlay)
{
int fd;
char *tmp;
@@ -164,7 +203,6 @@ static int create_testfile(unsigned int use_overlay)
return 0;
}
-
/* read_testfile - mmap testfile and read every page.
* This functions measures how many I/O and time it takes to fully
* read contents of test file.
@@ -194,7 +232,7 @@ static void read_testfile(int do_readahead, const char *fname, size_t fsize,
if (do_readahead) {
cached_start = get_cached_size();
do {
- TEST(readahead(fd, offset, fsize - offset));
+ TEST(readahead_func(fd, offset, fsize - offset));
if (TST_RET != 0) {
check_ret(0);
break;
@@ -256,17 +294,24 @@ static void read_testfile(int do_readahead, const char *fname, size_t fsize,
SAFE_CLOSE(fd);
}
-static void test_readahead(unsigned int use_overlay)
+static void test_readahead(unsigned int n)
{
unsigned long read_bytes, read_bytes_ra;
long usec, usec_ra;
unsigned long cached_max, cached_low, cached, cached_ra;
char proc_io_fname[128];
+ struct tcase *tc = &tcases[n];
+
+ tst_res(TINFO, "Test #%d: %s", n, tc->tname);
+
sprintf(proc_io_fname, "/proc/%u/io", getpid());
- if (create_testfile(use_overlay) != 0)
+ if (create_testfile(tc->use_overlay) != 0)
return;
+ /* Use either readahead() syscall or POSIX_FADV_WILLNEED */
+ readahead_func = tc->use_fadvise ? fadvise_willneed : libc_readahead;
+
/* find out how much can cache hold if we read whole file */
read_testfile(0, testfile, testfile_size, &read_bytes, &usec, &cached);
cached_max = get_cached_size();
@@ -357,7 +402,7 @@ static struct tst_test test = {
.cleanup = cleanup,
.options = options,
.test = test_readahead,
- .tcnt = 2, /* Repeat with overlayfs */
+ .tcnt = ARRAY_SIZE(tcases),
};
#else /* __NR_readahead */
--
2.17.1
