[PATCH] fiemap: Allow to specify range to fiemap

Nikolay Borisov
2017-08-10T11:07:50Z

Add 2 additional, optional, arguments to the embedded fiemap command,
that way one can specify exact ranges to be fiemapped. This will be used
for a btrfs test. Since the arguments are optional, omitting them just
retains the old behavior.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
io/fiemap.c | 34 ++++++++++++++++++++++++++++++++--
1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/io/fiemap.c b/io/fiemap.c
index 75e8820..a3c0c89 100644
--- a/io/fiemap.c
+++ b/io/fiemap.c
@@ -216,7 +216,11 @@ fiemap_f(
int flg_w = 5;
__u64 blocksize = 512;
__u64 last_logical = 0;
+ __u64 len = -1LL;
struct stat st;
+ size_t fsblocksize, fssectsize;
+
+ init_cvtnum(&fsblocksize, &fssectsize);

while ((c = getopt(argc, argv, "aln:v")) != EOF) {
switch (c) {
@@ -237,6 +241,32 @@ fiemap_f(
}
}

+ if (argc == optind + 2) {
+ off64_t start_offset = cvtnum(fsblocksize, fssectsize, argv[optind]);
+ if (start_offset < 0) {
+ printf("non-numeric offset argument -- %s\n", argv[optind]);
+ return 0;
+ }
+ last_logical = start_offset;
+ last_logical = strtoull(argv[optind], NULL, 10);
+
+ optind++;
+
+ off64_t length = cvtnum(fsblocksize, fssectsize, argv[optind]);
+ if (length < 0) {
+ printf("non-numeric len argument -- %s\n", argv[optind]);
+ return 0;
+ }
+ len = length;
+ } else if (argc == optind + 1) {
+ off64_t start_offset = cvtnum(fsblocksize, fssectsize, argv[optind]);
+ if (last_logical < 0) {
+ printf("non-numeric offset argument -- %s\n", argv[optind]);
+ return 0;
+ }
+ last_logical = start_offset;
+ }
+
if (max_extents)
num_extents = min(num_extents, max_extents);
map_size = sizeof(struct fiemap) +
@@ -259,7 +289,7 @@ fiemap_f(
memset(fiemap, 0, map_size);
fiemap->fm_flags = fiemap_flags;
fiemap->fm_start = last_logical;
- fiemap->fm_length = -1LL;
+ fiemap->fm_length = len;
fiemap->fm_extent_count = num_extents;

ret = ioctl(file->fd, FS_IOC_FIEMAP, (unsigned long)fiemap);
@@ -350,7 +380,7 @@ fiemap_init(void)
fiemap_cmd.argmin = 0;
fiemap_cmd.argmax = -1;
fiemap_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
- fiemap_cmd.args = _("[-alv] [-n nx]");
+ fiemap_cmd.args = _("[-alv] [-n nx] [start offset] [len]");
fiemap_cmd.oneline = _("print block mapping for a file");
fiemap_cmd.help = fiemap_help;

--
2.7.4