[f2fs-dev] [PATCH] f2fs_io: fix output of do_read()

[Chao Yu]

echo 1 > file
f2fs_io read 1 0 1 dio 4096 ./file
Read 0 bytes total_time = 17 us, print 4096 bytes:
00000000 : ffffffd537 ffffffc957 0500 0000 0000 0000 0000 0000
00000100 : 0000 0000 0000 0000 0000 0000 0000 0000
00000200 : 0000 0000 0000 0000 0000 0000 0000 0000
00000300 : 0000 0000 0000 0000 ffffffc10f 0200 0000 0000

For the case reading across EOF, it missed to copy returned
data to print_buf.

After:
f2fs_io read 1 0 1 dio 4096 ./file
pread expected: 4096, readed: 2
Read 2 bytes total_time = 177 us, print 4096 bytes:
00000000 : 310a 0000 0000 0000 0000 0000 0000 0000

Signed-off-by: Chao Yu <c...@kernel.org>
---
 tools/f2fs_io/f2fs_io.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/f2fs_io/f2fs_io.c b/tools/f2fs_io/f2fs_io.c
index a7b593a..79b4d04 100644
--- a/tools/f2fs_io/f2fs_io.c
+++ b/tools/f2fs_io/f2fs_io.c
@@ -867,8 +867,15 @@ static void do_read(int argc, char **argv, const struct 
cmd_desc *cmd)
        if (!do_mmap) {
                for (i = 0; i < count; i++) {
                        ret = pread(fd, buf, buf_size, offset + buf_size * i);
-                       if (ret != buf_size)
+                       if (ret != buf_size) {
+                               printf("pread expected: %"PRIu64", readed: 
%"PRIu64"\n",
+                                               buf_size, ret);
+                               if (ret > 0) {
+                                       read_cnt += ret;
+                                       memcpy(print_buf, buf, print_bytes);
+                               }
                                break;
+                       }
 
                        read_cnt += ret;
                        if (i == 0)
-- 
2.40.1



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