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Diffstat (limited to 'fs/nilfs2/the_nilfs.c')
-rw-r--r--fs/nilfs2/the_nilfs.c73
1 files changed, 65 insertions, 8 deletions
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index c8b89b4f94e0..2064e6473d30 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -13,6 +13,7 @@
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/random.h>
+#include <linux/log2.h>
#include <linux/crc32.h>
#include "nilfs.h"
#include "segment.h"
@@ -193,6 +194,34 @@ static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
}
/**
+ * nilfs_get_blocksize - get block size from raw superblock data
+ * @sb: super block instance
+ * @sbp: superblock raw data buffer
+ * @blocksize: place to store block size
+ *
+ * nilfs_get_blocksize() calculates the block size from the block size
+ * exponent information written in @sbp and stores it in @blocksize,
+ * or aborts with an error message if it's too large.
+ *
+ * Return Value: On success, 0 is returned. If the block size is too
+ * large, -EINVAL is returned.
+ */
+static int nilfs_get_blocksize(struct super_block *sb,
+ struct nilfs_super_block *sbp, int *blocksize)
+{
+ unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
+
+ if (unlikely(shift_bits >
+ ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)) {
+ nilfs_err(sb, "too large filesystem blocksize: 2 ^ %u KiB",
+ shift_bits);
+ return -EINVAL;
+ }
+ *blocksize = BLOCK_SIZE << shift_bits;
+ return 0;
+}
+
+/**
* load_nilfs - load and recover the nilfs
* @nilfs: the_nilfs structure to be released
* @sb: super block instance used to recover past segment
@@ -245,11 +274,15 @@ int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
/* verify consistency between two super blocks */
- blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
+ err = nilfs_get_blocksize(sb, sbp[0], &blocksize);
+ if (err)
+ goto scan_error;
+
if (blocksize != nilfs->ns_blocksize) {
nilfs_warn(sb,
"blocksize differs between two super blocks (%d != %d)",
blocksize, nilfs->ns_blocksize);
+ err = -EINVAL;
goto scan_error;
}
@@ -443,11 +476,33 @@ static int nilfs_valid_sb(struct nilfs_super_block *sbp)
return crc == le32_to_cpu(sbp->s_sum);
}
-static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
+/**
+ * nilfs_sb2_bad_offset - check the location of the second superblock
+ * @sbp: superblock raw data buffer
+ * @offset: byte offset of second superblock calculated from device size
+ *
+ * nilfs_sb2_bad_offset() checks if the position on the second
+ * superblock is valid or not based on the filesystem parameters
+ * stored in @sbp. If @offset points to a location within the segment
+ * area, or if the parameters themselves are not normal, it is
+ * determined to be invalid.
+ *
+ * Return Value: true if invalid, false if valid.
+ */
+static bool nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
{
- return offset < ((le64_to_cpu(sbp->s_nsegments) *
- le32_to_cpu(sbp->s_blocks_per_segment)) <<
- (le32_to_cpu(sbp->s_log_block_size) + 10));
+ unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
+ u32 blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
+ u64 nsegments = le64_to_cpu(sbp->s_nsegments);
+ u64 index;
+
+ if (blocks_per_segment < NILFS_SEG_MIN_BLOCKS ||
+ shift_bits > ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)
+ return true;
+
+ index = offset >> (shift_bits + BLOCK_SIZE_BITS);
+ do_div(index, blocks_per_segment);
+ return index < nsegments;
}
static void nilfs_release_super_block(struct the_nilfs *nilfs)
@@ -586,9 +641,11 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
if (err)
goto failed_sbh;
- blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
- if (blocksize < NILFS_MIN_BLOCK_SIZE ||
- blocksize > NILFS_MAX_BLOCK_SIZE) {
+ err = nilfs_get_blocksize(sb, sbp, &blocksize);
+ if (err)
+ goto failed_sbh;
+
+ if (blocksize < NILFS_MIN_BLOCK_SIZE) {
nilfs_err(sb,
"couldn't mount because of unsupported filesystem blocksize %d",
blocksize);