ext4: create a new BH_Verified flag to avoid unnecessary metadata validation
Create a new BH_Verified flag to indicate that we've verified all the
data in a buffer_head for correctness. This allows us to bypass
expensive verification steps when they are not necessary without
missing them when they are.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index abcdeab..8c1334e 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -412,6 +412,26 @@
return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
}
+static int __ext4_ext_check_block(const char *function, unsigned int line,
+ struct inode *inode,
+ struct ext4_extent_header *eh,
+ int depth,
+ struct buffer_head *bh)
+{
+ int ret;
+
+ if (buffer_verified(bh))
+ return 0;
+ ret = ext4_ext_check(inode, eh, depth);
+ if (ret)
+ return ret;
+ set_buffer_verified(bh);
+ return ret;
+}
+
+#define ext4_ext_check_block(inode, eh, depth, bh) \
+ __ext4_ext_check_block(__func__, __LINE__, inode, eh, depth, bh)
+
#ifdef EXT_DEBUG
static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
{
@@ -668,8 +688,6 @@
i = depth;
/* walk through the tree */
while (i) {
- int need_to_validate = 0;
-
ext_debug("depth %d: num %d, max %d\n",
ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
@@ -688,8 +706,6 @@
put_bh(bh);
goto err;
}
- /* validate the extent entries */
- need_to_validate = 1;
}
eh = ext_block_hdr(bh);
ppos++;
@@ -703,7 +719,7 @@
path[ppos].p_hdr = eh;
i--;
- if (need_to_validate && ext4_ext_check(inode, eh, i))
+ if (ext4_ext_check_block(inode, eh, i, bh))
goto err;
}
@@ -1344,7 +1360,8 @@
return -EIO;
eh = ext_block_hdr(bh);
/* subtract from p_depth to get proper eh_depth */
- if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
+ if (ext4_ext_check_block(inode, eh,
+ path->p_depth - depth, bh)) {
put_bh(bh);
return -EIO;
}
@@ -1357,7 +1374,7 @@
if (bh == NULL)
return -EIO;
eh = ext_block_hdr(bh);
- if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
+ if (ext4_ext_check_block(inode, eh, path->p_depth - depth, bh)) {
put_bh(bh);
return -EIO;
}
@@ -2644,8 +2661,8 @@
err = -EIO;
break;
}
- if (ext4_ext_check(inode, ext_block_hdr(bh),
- depth - i - 1)) {
+ if (ext4_ext_check_block(inode, ext_block_hdr(bh),
+ depth - i - 1, bh)) {
err = -EIO;
break;
}
diff --git a/include/linux/jbd_common.h b/include/linux/jbd_common.h
index 6230f85..6133679 100644
--- a/include/linux/jbd_common.h
+++ b/include/linux/jbd_common.h
@@ -12,6 +12,7 @@
BH_State, /* Pins most journal_head state */
BH_JournalHead, /* Pins bh->b_private and jh->b_bh */
BH_Unshadow, /* Dummy bit, for BJ_Shadow wakeup filtering */
+ BH_Verified, /* Metadata block has been verified ok */
BH_JBDPrivateStart, /* First bit available for private use by FS */
};
@@ -24,6 +25,7 @@
BUFFER_FNS(RevokeValid, revokevalid)
TAS_BUFFER_FNS(RevokeValid, revokevalid)
BUFFER_FNS(Freed, freed)
+BUFFER_FNS(Verified, verified)
static inline struct buffer_head *jh2bh(struct journal_head *jh)
{