[PATCH v2] mkfs.ubifs: free-space-fixup: note supported kernels

[Ben Gardiner]

The free space fixup flag will only have an action taken on up-to-date
kernels.

Note in the help text and comment that kernel release 2.6.40 is required
for the free space fixup to be performed.

Signed-off-by: Ben Gardiner <bengardiner at nanometrics.ca>
CC: Matthew L. Creech <mlcreech at gmail.com>

---
Changes since v1:
 * updated references to the kernel release to reflect the reality that
   2.6.39 is a done deal

---
 mkfs.ubifs/mkfs.ubifs.c  |    4 +++-
 mkfs.ubifs/ubifs-media.h |    2 ++
 2 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/mkfs.ubifs/mkfs.ubifs.c b/mkfs.ubifs/mkfs.ubifs.c
index 96e17a3..1ce1db3 100644
--- a/mkfs.ubifs/mkfs.ubifs.c
+++ b/mkfs.ubifs/mkfs.ubifs.c
@@ -184,7 +184,9 @@ static const char *helptext =
 "                         how many percent better zlib should compress to make\n"
 "                         mkfs.ubifs use zlib instead of LZO (default 20%)\n"
 "-f, --fanout=NUM         fanout NUM (default: 8)\n"
-"-F, --space-fixup        fixup free space on first mount (needed for some NANDs)\n"
+"-F, --space-fixup        fixup free space on first mount (needed for some NANDs;\n"
+"                         the free space fixup will be performed only by kernel\n"
+"                         releases 2.6.40 or greater)\n"
 "-k, --keyhash=TYPE       key hash type - \"r5\" or \"test\" (default: \"r5\")\n"
 "-p, --orph-lebs=COUNT    count of erase blocks for orphans (default: 1)\n"
 "-D, --devtable=FILE      use device table FILE\n"
diff --git a/mkfs.ubifs/ubifs-media.h b/mkfs.ubifs/ubifs-media.h
index fe62d0e..16683de 100644
--- a/mkfs.ubifs/ubifs-media.h
+++ b/mkfs.ubifs/ubifs-media.h
@@ -374,6 +374,8 @@ enum {
  *
  * UBIFS_FLG_BIGLPT: if "big" LPT model is used if set
  * UBIFS_FLG_SPACE_FIXUP: first-mount "fixup" of free space within LEBs needed
+ *                        the free space fixup will be performed only by kernel
+ *                        releases 2.6.40 or greater.
  */
 enum {
 	UBIFS_FLG_BIGLPT = 0x02,
-- 
1.7.4.1