Commit 2bcf0021 authored by Artem Bityutskiy's avatar Artem Bityutskiy

UBIFS: do not check data crc by default

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_checksummingSigned-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent cce3f612
...@@ -82,12 +82,12 @@ Mount options ...@@ -82,12 +82,12 @@ Mount options
bulk_read read more in one go to take advantage of flash bulk_read read more in one go to take advantage of flash
media that read faster sequentially media that read faster sequentially
no_bulk_read (*) do not bulk-read 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 improve read performance. Use this option only
if the flash media is highly reliable. The effect if the flash media is highly reliable. The effect
of this option is that corruption of the contents of this option is that corruption of the contents
of a file can go unnoticed. 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=none override default compressor and set it to "none"
compr=lzo override default compressor and set it to "lzo" compr=lzo override default compressor and set it to "lzo"
compr=zlib override default compressor and set it to "zlib" compr=zlib override default compressor and set it to "zlib"
......
...@@ -1977,6 +1977,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent) ...@@ -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->old_buds);
INIT_LIST_HEAD(&c->orph_list); INIT_LIST_HEAD(&c->orph_list);
INIT_LIST_HEAD(&c->orph_new); INIT_LIST_HEAD(&c->orph_new);
c->no_chk_data_crc = 1;
c->vfs_sb = sb; c->vfs_sb = sb;
c->highest_inum = UBIFS_FIRST_INO; c->highest_inum = UBIFS_FIRST_INO;
......
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