blockdev: add note about --setbsz usability

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/disk-utils/blockdev.8 b/disk-utils/blockdev.8
index 2b3d64c88f3d5e0d876ea4b1273175e478c36042..f4282daaed6d9b8569a760102ba96c22b611479f 100644 (file)
--- a/disk-utils/blockdev.8
+++ b/disk-utils/blockdev.8
@@ -68,7 +68,9 @@ Get size in 512-byte sectors.
 .IP "\fB\-\-rereadpt\fP"
 Reread partition table
 .IP "\fB\-\-setbsz\fP \fIbytes\fP"
-Set blocksize.
+Set blocksize. Note that the block size is specific to the current file
+descriptor opening the block device, so the change of block size only persists
+for as long as blockdev has the device open, and is lost once blockdev exits.
 .IP "\fB\-\-setfra\fP \fIsectors\fP"
 Set filesystem readahead (same like --setra on 2.6 kernels).
 .IP "\fB\-\-setra\fP \fIsectors\fP"

diff --git a/disk-utils/blockdev.c b/disk-utils/blockdev.c
index 4543818bd4f90dedcc9a4e6c19e7865afc1d7741..d030217d72d41e9fbb00ecee58bd8be0009d5e93 100644 (file)
--- a/disk-utils/blockdev.c
+++ b/disk-utils/blockdev.c
@@ -127,7 +127,7 @@ static const struct bdc bdcms[] =
                .argname = "<bytes>",
                .argtype = ARG_INT,
                .flags = FL_NORESULT,
-               .help = N_("set blocksize")
+               .help = N_("set blocksize on file descriptor opening the block device")
        },{
                IOCTL_ENTRY(BLKGETSIZE),
                .name = "--getsize",