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Message-ID: <20111008073535.17888.19955.stgit@elm3c44.beaverton.ibm.com>
Date: Sat, 08 Oct 2011 00:35:35 -0700
From: "Darrick J. Wong" <djwong@...ibm.com>
To: Andreas Dilger <adilger.kernel@...ger.ca>,
Theodore Tso <tytso@....edu>,
"Darrick J. Wong" <djwong@...ibm.com>
Cc: Sunil Mushran <sunil.mushran@...cle.com>,
Amir Goldstein <amir73il@...il.com>,
Andi Kleen <andi@...stfloor.org>,
Mingming Cao <cmm@...ibm.com>,
Joel Becker <jlbec@...lplan.org>, linux-ext4@...r.kernel.org,
Coly Li <colyli@...il.com>
Subject: [PATCH 22/47] libext2fs: Add dx_root/dx_node checksum calculation and
verification helpers
Verify and calculate checksums of htree internal node blocks.
Signed-off-by: Darrick J. Wong <djwong@...ibm.com>
---
lib/ext2fs/csum.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++
lib/ext2fs/dirhash.c | 41 ++++++++++++++++++++
lib/ext2fs/ext2fs.h | 6 +++
3 files changed, 150 insertions(+), 0 deletions(-)
diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
index 7f2d5af..cd788c8 100644
--- a/lib/ext2fs/csum.c
+++ b/lib/ext2fs/csum.c
@@ -30,6 +30,109 @@
#define STATIC static
#endif
+static errcode_t ext2fs_dx_csum(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_dir_entry *dirent,
+ __u32 *crc, int count_offset, int count)
+{
+ errcode_t retval = 0;
+ char *buf = (char *)dirent;
+ int size;
+ __u32 ncrc;
+
+ size = count_offset + (count * sizeof(struct ext2_dx_entry));
+
+ /*
+ * The dx_root/dx_entry structures are always accessed via
+ * le*_to_cpu helpers and don't need swapping here. However, the
+ * dirent container fields need to be swapped.
+ */
+#ifdef WORDS_BIGENDIAN
+ retval = ext2fs_get_mem(fs->blocksize, &buf);
+ if (retval)
+ return retval;
+ memcpy(buf, dirent, fs->blocksize);
+ retval = ext2fs_dirent_swab_out(fs, buf, 0);
+ if (retval)
+ goto out;
+#endif
+
+ inum = ext2fs_cpu_to_le32(inum);
+ ncrc = ext2fs_crc32c_le(~0, fs->super->s_uuid,
+ sizeof(fs->super->s_uuid));
+ ncrc = ext2fs_crc32c_le(ncrc, (unsigned char *)&inum, sizeof(inum));
+ ncrc = ext2fs_crc32c_le(ncrc, (unsigned char *)buf, size);
+ *crc = ncrc;
+
+#ifdef WORDS_BIGENDIAN
+out:
+ ext2fs_free_mem(&buf);
+#endif
+
+ return retval;
+}
+
+int ext2fs_dx_csum_verify(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_dir_entry *dirent)
+{
+ __u32 calculated;
+ errcode_t retval;
+ struct ext2_dx_countlimit *c;
+ struct ext2_dx_tail *t;
+ int count_offset, limit, count;
+
+ if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return 1;
+
+ c = ext2fs_get_dx_countlimit(fs, dirent, &count_offset);
+ if (!c)
+ return 1;
+ limit = ext2fs_le16_to_cpu(c->limit);
+ count = ext2fs_le16_to_cpu(c->count);
+ if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
+ fs->blocksize - sizeof(struct ext2_dx_tail))
+ return 0;
+ /* htree structs are accessed in LE order */
+ t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
+ retval = ext2fs_dx_csum(fs, inum, dirent, &calculated, count_offset,
+ count);
+ if (retval)
+ return 0;
+
+ return ext2fs_le32_to_cpu(t->checksum) == calculated;
+}
+
+errcode_t ext2fs_dx_csum_set(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_dir_entry *dirent)
+{
+ __u32 crc;
+ errcode_t retval = 0;
+ struct ext2_dx_countlimit *c;
+ struct ext2_dx_tail *t;
+ int count_offset, limit, count;
+
+ if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return 0;
+
+ c = ext2fs_get_dx_countlimit(fs, dirent, &count_offset);
+ if (!c)
+ return 0;
+ limit = ext2fs_le16_to_cpu(c->limit);
+ count = ext2fs_le16_to_cpu(c->count);
+ if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
+ fs->blocksize - sizeof(struct ext2_dx_tail))
+ return 0;
+ t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
+
+ /* htree structs are accessed in LE order */
+ retval = ext2fs_dx_csum(fs, inum, dirent, &crc, count_offset, count);
+ if (retval)
+ return retval;
+ t->checksum = ext2fs_cpu_to_le32(crc);
+ return retval;
+}
+
#define EXT3_EXTENT_TAIL_OFFSET(hdr) (sizeof(struct ext3_extent_header) + \
(sizeof(struct ext3_extent) * ext2fs_le16_to_cpu((hdr)->eh_max)))
diff --git a/lib/ext2fs/dirhash.c b/lib/ext2fs/dirhash.c
index c4ac94e..305e9ad 100644
--- a/lib/ext2fs/dirhash.c
+++ b/lib/ext2fs/dirhash.c
@@ -259,3 +259,44 @@ errcode_t ext2fs_dirhash(int version, const char *name, int len,
*ret_minor_hash = minor_hash;
return 0;
}
+
+struct ext2_dx_countlimit *ext2fs_get_dx_countlimit(ext2_filsys fs,
+ struct ext2_dir_entry *dirent, int *offset)
+{
+ struct ext2_dir_entry *dp;
+ struct ext2_dx_root_info *root;
+ struct ext2_dx_countlimit *c;
+ int count_offset, max_sane_entries;
+ unsigned int rec_len;
+ errcode_t retval;
+
+ retval = ext2fs_get_rec_len(fs, dirent, &rec_len);
+ if (retval)
+ return NULL;
+
+ if (rec_len == fs->blocksize && dirent->name_len == 0)
+ count_offset = 8;
+ else if (rec_len == 12) {
+ dp = (struct ext2_dir_entry *)(((void *)dirent) + rec_len);
+ retval = ext2fs_get_rec_len(fs, dp, &rec_len);
+ if (retval || rec_len != fs->blocksize - 12)
+ return NULL;
+ root = (struct ext2_dx_root_info *)(((void *)dp + 12));
+ if (root->reserved_zero ||
+ root->info_length != sizeof(struct ext2_dx_root_info))
+ return NULL;
+ count_offset = 32;
+ } else
+ return NULL;
+
+ c = (struct ext2_dx_countlimit *)(((void *)dirent) + count_offset);
+ max_sane_entries = (fs->blocksize - count_offset) /
+ sizeof(struct ext2_dx_entry);
+ if (ext2fs_le16_to_cpu(c->limit) > max_sane_entries ||
+ ext2fs_le16_to_cpu(c->count) > max_sane_entries)
+ return NULL;
+
+ if (offset)
+ *offset = count_offset;
+ return c;
+}
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index bf2a9e0..7836fd2 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -929,6 +929,10 @@ extern __u32 ext2fs_crc32c_be(__u32 crc, unsigned char const *p, size_t len);
extern __u32 ext2fs_crc32c_le(__u32 crc, unsigned char const *p, size_t len);
/* csum.c */
+extern errcode_t ext2fs_dx_csum_set(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_dir_entry *dirent);
+extern int ext2fs_dx_csum_verify(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_dir_entry *dirent);
extern errcode_t ext2fs_extent_block_csum_set(ext2_filsys fs,
ext2_ino_t inum,
struct ext3_extent_header *eh);
@@ -1016,6 +1020,8 @@ extern errcode_t ext2fs_write_dir_block3(ext2_filsys fs, blk64_t block,
void *buf, int flags);
/* dirhash.c */
+extern struct ext2_dx_countlimit *ext2fs_get_dx_countlimit(ext2_filsys fs,
+ struct ext2_dir_entry *dirent, int *offset);
extern errcode_t ext2fs_dirhash(int version, const char *name, int len,
const __u32 *seed,
ext2_dirhash_t *ret_hash,
--
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