ocfs2: Validate metadata only when it's read from disk.
Add an optional validation hook to ocfs2_read_blocks(). Now the
validation function is only called when a block was actually read off of
disk. It is not called when the buffer was in cache.
We add a buffer state bit BH_NeedsValidate to flag these buffers. It
must always be one higher than the last JBD2 buffer state bit.
The dinode, dirblock, extent_block, and xattr_block validators are
lifted to this scheme directly. The group_descriptor validator needs to
be split into two pieces. The first part only needs the gd buffer and
is passed to ocfs2_read_block(). The second part requires the dinode as
well, and is called every time. It's only 3 compares, so it's tiny.
This also allows us to clean up the non-fatal gd check used by resize.c.
It now has no magic argument.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c
index 3a178ec..0e9eed0 100644
--- a/fs/ocfs2/buffer_head_io.c
+++ b/fs/ocfs2/buffer_head_io.c
@@ -39,6 +39,19 @@
#include "buffer_head_io.h"
+/*
+ * Bits on bh->b_state used by ocfs2.
+ *
+ * These MUST be after the JBD2 bits. Currently BH_Unshadow is the last
+ * JBD2 bit.
+ */
+enum ocfs2_state_bits {
+ BH_NeedsValidate = BH_Unshadow + 1,
+};
+
+/* Expand the magic b_state functions */
+BUFFER_FNS(NeedsValidate, needs_validate);
+
int ocfs2_write_block(struct ocfs2_super *osb, struct buffer_head *bh,
struct inode *inode)
{
@@ -166,7 +179,9 @@
}
int ocfs2_read_blocks(struct inode *inode, u64 block, int nr,
- struct buffer_head *bhs[], int flags)
+ struct buffer_head *bhs[], int flags,
+ int (*validate)(struct super_block *sb,
+ struct buffer_head *bh))
{
int status = 0;
int i, ignore_cache = 0;
@@ -298,6 +313,8 @@
clear_buffer_uptodate(bh);
get_bh(bh); /* for end_buffer_read_sync() */
+ if (validate)
+ set_buffer_needs_validate(bh);
bh->b_end_io = end_buffer_read_sync;
submit_bh(READ, bh);
continue;
@@ -328,6 +345,20 @@
bhs[i] = NULL;
continue;
}
+
+ if (buffer_needs_validate(bh)) {
+ /* We never set NeedsValidate if the
+ * buffer was held by the journal, so
+ * that better not have changed */
+ BUG_ON(buffer_jbd(bh));
+ clear_buffer_needs_validate(bh);
+ status = validate(inode->i_sb, bh);
+ if (status) {
+ put_bh(bh);
+ bhs[i] = NULL;
+ continue;
+ }
+ }
}
/* Always set the buffer in the cache, even if it was