On Wed, Jun 23, 2010 at 5:55 PM, Joel Becker <[email protected]> wrote:
> These don't need to be const. Sure, they don't change, but
> you're not signifying anything special with them (like passing them to a
> subfunction or something).
Well, I am signifying that I do not intend to change them... "const"
is just a compile-time assertion, and like all compile-time
assertions, it has no effect on the generated code. So the only
issues are readability and maintainability. In my experience, using
"const" consistently helps with both. But I know it is not really the
Linux Way.
> And you don't really need the clusters temporary.
Here again, the generated code is identical, so the question is human
consumption. I find that factoring out sub-expressions and giving
them meaningful names makes code easier to read and to understand.
(Not to mention taking two lines instead of three.) For example, I
believe my version is less likely to wind up with the "-1" in the
wrong place. :-)
But your house = your rules. Updated patch follows. I will try to
find time to test today or tomorrow.
Thanks!
- Pat
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 0eaa929..d32c800 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1991,6 +1991,46 @@ static int ocfs2_setup_osb_uuid(struct
ocfs2_super *osb, const unsigned char *uu
return 0;
}
+/* Check to make sure entire volume is addressable on this system. */
+static int ocfs2_check_addressable(struct ocfs2_super *osb,
+ struct ocfs2_dinode *di)
+{
+ int status = 0;
+ u64 max_block =
+ ocfs2_clusters_to_blocks(osb->sb,
+ le32_to_cpu(di->i_clusters)) - 1;
+
+ /* Absolute addressability check (borrowed from ext4/super.c) */
+ if ((max_block >
+ (sector_t)(~0LL) >> (osb->sb->s_blocksize_bits - 9)) ||
+ (max_block > (pgoff_t)(~0LL) >> (PAGE_CACHE_SHIFT -
+ osb->sb->s_blocksize_bits))) {
+ mlog(ML_ERROR, "Volume too large "
+ "to mount safely on this system");
+ status = -EFBIG;
+ goto out;
+ }
+
+ /* 32-bit block number is always OK. */
+ if (max_block <= (u32)~0UL)
+ goto out;
+
+ /* Volume is "huge", so see if our journal is new enough to
+ support it. */
+ if (!(OCFS2_HAS_COMPAT_FEATURE(osb->sb,
+ OCFS2_FEATURE_COMPAT_JBD2_SB) &&
+ jbd2_journal_check_used_features(osb->journal->j_journal, 0, 0,
+ JBD2_FEATURE_INCOMPAT_64BIT))) {
+ mlog(ML_ERROR, "The journal cannot address the entire volume. "
+ "Enable the 'block64' journal option with tunefs.ocfs2");
+ status = -EFBIG;
+ goto out;
+ }
+
+ out:
+ return status;
+}
+
static int ocfs2_initialize_super(struct super_block *sb,
struct buffer_head *bh,
int sector_size,
@@ -2215,13 +2255,9 @@ static int ocfs2_initialize_super(struct super_block *sb,
goto bail;
}
- if (ocfs2_clusters_to_blocks(osb->sb, le32_to_cpu(di->i_clusters) - 1)
- > (u32)~0UL) {
- mlog(ML_ERROR, "Volume might try to write to blocks beyond "
- "what jbd can address in 32 bits.\n");
- status = -EINVAL;
+ status = ocfs2_check_addressable(osb, di);
+ if (status)
goto bail;
- }
if (ocfs2_setup_osb_uuid(osb, di->id2.i_super.s_uuid,
sizeof(di->id2.i_super.s_uuid))) {
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