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| author | Artem Bityutskiy <Artem.Bityutskiy@nokia.com> | 2009-01-27 16:12:31 +0200 |
|---|---|---|
| committer | Artem Bityutskiy <Artem.Bityutskiy@nokia.com> | 2009-01-27 16:25:10 +0200 |
| commit | 6f7ab6d458bbfc2f55d295fa3e6b9e69cdb1d517 (patch) | |
| tree | 7d07f5ff88d205a652998c2fd281e7123ba9a112 /fs/ubifs/tnc.c | |
| parent | 6ba87c9b920bea8c2703308d31eb7de925242c30 (diff) | |
| download | lwn-6f7ab6d458bbfc2f55d295fa3e6b9e69cdb1d517.tar.gz lwn-6f7ab6d458bbfc2f55d295fa3e6b9e69cdb1d517.zip | |
UBIFS: fix no_chk_data_crc
When data CRC checking is disabled, UBIFS returns incorrect return
code from the 'try_read_node()' function (0 instead of 1, which means
CRC error), which make the caller re-read the data node again, but using
a different code patch, so the second read is fine. Thus, we read the
same node twice. And the result of this is that UBIFS is slower
with no_chk_data_crc option than it is with chk_data_crc option.
This patches fixes the problem.
Reported-by: Reuben Dowle <Reuben.Dowle@navico.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Diffstat (limited to 'fs/ubifs/tnc.c')
| -rw-r--r-- | fs/ubifs/tnc.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c index f7e36f545527..fa28a84c6a1b 100644 --- a/fs/ubifs/tnc.c +++ b/fs/ubifs/tnc.c @@ -443,6 +443,11 @@ static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr, * This function performs that same function as ubifs_read_node except that * it does not require that there is actually a node present and instead * the return code indicates if a node was read. + * + * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc + * is true (it is controlled by corresponding mount option). However, if + * @c->always_chk_crc is true, @c->no_chk_data_crc is ignored and CRC is always + * checked. */ static int try_read_node(const struct ubifs_info *c, void *buf, int type, int len, int lnum, int offs) @@ -470,9 +475,8 @@ static int try_read_node(const struct ubifs_info *c, void *buf, int type, if (node_len != len) return 0; - if (type == UBIFS_DATA_NODE && !c->always_chk_crc) - if (c->no_chk_data_crc) - return 0; + if (type == UBIFS_DATA_NODE && !c->always_chk_crc && c->no_chk_data_crc) + return 1; crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8); node_crc = le32_to_cpu(ch->crc); @@ -1506,7 +1510,7 @@ out: * * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares - * maxumum possible amount of nodes for bulk-read. + * maximum possible amount of nodes for bulk-read. */ int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu) { |