Precompute the FS UUID checksum seed that is used for all metadata checksumming
operations and store it in ext2_filsys.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
e2fsck/super.c | 1 +
lib/ext2fs/ext2fs.h | 14 ++++++++++++++
lib/ext2fs/openfs.c | 2 ++
misc/mke2fs.c | 1 +
4 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/e2fsck/super.c b/e2fsck/super.c
index afec4b4..99c0b84 100644
--- a/e2fsck/super.c
+++ b/e2fsck/super.c
@@ -719,6 +719,7 @@ void check_super_block(e2fsck_t ctx)
if (!(ctx->options & E2F_OPT_READONLY) && uuid_is_null(sb->s_uuid)) {
if (fix_problem(ctx, PR_0_ADD_UUID, &pctx)) {
uuid_generate(sb->s_uuid);
+ ext2fs_init_csum_seed(fs);
fs->flags |= EXT2_FLAG_DIRTY;
fs->flags &= ~EXT2_FLAG_MASTER_SB_ONLY;
}
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 16c4567..c00032e 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -279,6 +279,9 @@ struct struct_ext2_filsys {
* Time at which e2fsck last updated the MMP block.
*/
long mmp_last_written;
+
+ /* Precomputed FS UUID checksum for seeding other checksums */
+ __u32 csum_seed;
};
#if EXT2_FLAT_INCLUDES
@@ -1424,6 +1427,7 @@ extern errcode_t ext2fs_write_bb_FILE(ext2_badblocks_list bb_list,
/* inline functions */
+extern void ext2fs_init_csum_seed(ext2_filsys fs);
extern errcode_t ext2fs_get_mem(unsigned long size, void *ptr);
extern errcode_t ext2fs_get_memalign(unsigned long size,
unsigned long align, void *ptr);
@@ -1476,6 +1480,16 @@ extern int ext2fs_fstat(int fd, ext2fs_struct_stat *buf);
#ifndef EXT2_CUSTOM_MEMORY_ROUTINES
#include <string.h>
+_INLINE_ void ext2fs_init_csum_seed(ext2_filsys fs)
+{
+ if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return;
+
+ fs->csum_seed = ext2fs_crc32c_le(~0, fs->super->s_uuid,
+ sizeof(fs->super->s_uuid));
+}
+
/*
* Allocate memory
*/
diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
index 40a52c5..6cb629e 100644
--- a/lib/ext2fs/openfs.c
+++ b/lib/ext2fs/openfs.c
@@ -298,6 +298,8 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
retval = EXT2_ET_CORRUPT_SUPERBLOCK;
goto cleanup;
}
+ /* Precompute the FS UUID to seed other checksums */
+ ext2fs_init_csum_seed(fs);
/*
* Read group descriptors
diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index 0ef2531..f2d7c81 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -2315,6 +2315,7 @@ int main (int argc, char *argv[])
}
} else
uuid_generate(fs->super->s_uuid);
+ ext2fs_init_csum_seed(fs);
/*
* Initialize the directory index variables
--
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