From: Artem Bityutskiy Date: Thu, 14 Mar 2013 08:49:23 +0000 (+0200) Subject: UBIFS: make space fixup work in the remount case X-Git-Tag: v3.9-rc6~19^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=67e753ca41782913d805ff4a8a2b0f60b26b7915;p=pandora-kernel.git UBIFS: make space fixup work in the remount case The UBIFS space fixup is a useful feature which allows to fixup the "broken" flash space at the time of the first mount. The "broken" space is usually the result of using a "dumb" industrial flasher which is not able to skip empty NAND pages and just writes all 0xFFs to the empty space, which has grave side-effects for UBIFS when UBIFS trise to write useful data to those empty pages. The fix-up feature works roughly like this: 1. mkfs.ubifs sets the fixup flag in UBIFS superblock when creating the image (see -F option) 2. when the file-system is mounted for the first time, UBIFS notices the fixup flag and re-writes the entire media atomically, which may take really a lot of time. 3. UBIFS clears the fixup flag in the superblock. This works fine when the file system is mounted R/W for the very first time. But it did not really work in the case when we first mount the file-system R/O, and then re-mount R/W. The reason was that we started the fixup procedure too late, which we cannot really do because we have to fixup the space before it starts being used. Signed-off-by: Artem Bityutskiy Reported-by: Mark Jackson Cc: stable@vger.kernel.org # 3.0+ --- Reading git-diff-tree failed