lkml.org 
[lkml]   [2012]   [Mar]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH 17/23] jbd2: Grab a reference to the crc32c driver only when necessary
From
Date
Obtain a reference to the crc32c driver only when the journal needs it for
checksum v2.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
---
fs/jbd2/Kconfig | 2 ++
fs/jbd2/journal.c | 25 +++++++++++++++++++++++++
include/linux/jbd2.h | 23 +++++++++++++++++++++++
3 files changed, 50 insertions(+), 0 deletions(-)


diff --git a/fs/jbd2/Kconfig b/fs/jbd2/Kconfig
index f32f346..69a48c2 100644
--- a/fs/jbd2/Kconfig
+++ b/fs/jbd2/Kconfig
@@ -1,6 +1,8 @@
config JBD2
tristate
select CRC32
+ select CRYPTO
+ select CRYPTO_CRC32C
help
This is a generic journaling layer for block devices that support
both 32-bit and 64-bit block numbers. It is currently used by
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index ac276b0..554f899 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1284,6 +1284,17 @@ static int journal_get_superblock(journal_t *journal)
goto out;
}

+ /* Load the checksum driver */
+ if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
+ journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
+ if (IS_ERR(journal->j_chksum_driver)) {
+ printk(KERN_ERR "JBD: Cannot load crc32c driver.\n");
+ err = PTR_ERR(journal->j_chksum_driver);
+ journal->j_chksum_driver = NULL;
+ goto out;
+ }
+ }
+
set_buffer_verified(bh);

return 0;
@@ -1440,6 +1451,8 @@ int jbd2_journal_destroy(journal_t *journal)
iput(journal->j_inode);
if (journal->j_revoke)
jbd2_journal_destroy_revoke(journal);
+ if (journal->j_chksum_driver)
+ crypto_free_shash(journal->j_chksum_driver);
kfree(journal->j_wbuf);
kfree(journal);

@@ -1556,6 +1569,18 @@ int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
sb->s_feature_compat &=
~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
+
+ /* Load the checksum driver */
+ if (journal->j_chksum_driver == NULL) {
+ journal->j_chksum_driver = crypto_alloc_shash("crc32c",
+ 0, 0);
+ if (IS_ERR(journal->j_chksum_driver)) {
+ printk(KERN_ERR "JBD: Cannot load crc32c "
+ "driver.\n");
+ journal->j_chksum_driver = NULL;
+ return 0;
+ }
+ }
}

/* If enabling v1 checksums, downgrade superblock */
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index c286153..320de7d 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -31,6 +31,7 @@
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/slab.h>
+#include <crypto/hash.h>
#endif

#define journal_oom_retry 1
@@ -965,6 +966,9 @@ struct journal_s
* superblock pointer here
*/
void *j_private;
+
+ /* Reference to checksum algorithm driver via cryptoapi */
+ struct crypto_shash *j_chksum_driver;
};

/*
@@ -1284,6 +1288,25 @@ static inline int jbd_space_needed(journal_t *journal)

extern int jbd_blocks_per_page(struct inode *inode);

+static inline u32 jbd2_chksum(journal_t *journal, u32 crc,
+ const void *address, unsigned int length)
+{
+ struct {
+ struct shash_desc shash;
+ char ctx[crypto_shash_descsize(journal->j_chksum_driver)];
+ } desc;
+ int err;
+
+ desc.shash.tfm = journal->j_chksum_driver;
+ desc.shash.flags = 0;
+ *(u32 *)desc.ctx = crc;
+
+ err = crypto_shash_update(&desc.shash, address, length);
+ BUG_ON(err);
+
+ return *(u32 *)desc.ctx;
+}
+
#ifdef __KERNEL__

#define buffer_trace_init(bh) do {} while (0)


\
 
 \ /
  Last update: 2012-03-06 21:55    [W:0.141 / U:5.128 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site