UBIFS: do not check data crc by default (2bcf0021) · Commits · 戴 / test

Change the default UBIFS behavior WRT data CRC checking. Currently, UBIFS checks data CRC when reading, which slows it down quite a bit, and this is the default option. However, it looks like in average user does not need this feature and would prefer faster read speed over extra reliability. And this seems to be de-facto standard that file-systems do not check data CRC every time they read from the media. Thus, make UBIFS default behavior so that it does not check data CRC. This corresponds to the no_chk_data_crc mount option. Those users who need extra protection can always enable it using the chk_data_crc option. Please, read more information about this feature here: http://www.linux-mtd.infradead.org/doc/ubifs.html#L_checksumming Signed-off-by:

Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Documentation/filesystems/ubifs.txt

+2 −2

Original line number	Diff line number	Diff line
		@@ -82,12 +82,12 @@ Mount options
		bulk_read read more in one go to take advantage of flash
		media that read faster sequentially
		no_bulk_read (*) do not bulk-read
		no_chk_data_crc skip checking of CRCs on data nodes in order to
		no_chk_data_crc (*) skip checking of CRCs on data nodes in order to
		improve read performance. Use this option only
		if the flash media is highly reliable. The effect
		of this option is that corruption of the contents
		of a file can go unnoticed.
		chk_data_crc (*) do not skip checking CRCs on data nodes
		chk_data_crc do not skip checking CRCs on data nodes
		compr=none override default compressor and set it to "none"
		compr=lzo override default compressor and set it to "lzo"
		compr=zlib override default compressor and set it to "zlib"

fs/ubifs/super.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1977,6 +1977,7 @@ static int ubifs_fill_super(struct super_block sb, void data, int silent)
		INIT_LIST_HEAD(&c->old_buds);
		INIT_LIST_HEAD(&c->orph_list);
		INIT_LIST_HEAD(&c->orph_new);
		c->no_chk_data_crc = 1;

		c->vfs_sb = sb;
		c->highest_inum = UBIFS_FIRST_INO;

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