[PATCH 40/45] ocfs2: Validate metadata only when it's read from disk.

From: Mark Fasheh
Date: Fri Dec 19 2008 - 17:08:30 EST

From: Joel Becker <joel.becker@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Mark Fasheh <mfasheh@xxxxxxxx>
---
fs/ocfs2/alloc.c | 17 +++-----
fs/ocfs2/buffer_head_io.c | 33 ++++++++++++++++-
fs/ocfs2/buffer_head_io.h | 27 ++++++++-----
fs/ocfs2/dir.c | 13 ++----
fs/ocfs2/inode.c | 18 ++------
fs/ocfs2/resize.c | 2 +-
fs/ocfs2/slot_map.c | 4 +-
fs/ocfs2/suballoc.c | 91 +++++++++++++++++++++++++++++++-------------
fs/ocfs2/suballoc.h | 15 +++----
fs/ocfs2/xattr.c | 26 ++++++-------
10 files changed, 149 insertions(+), 97 deletions(-)

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index f430cc6..e823a27 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -684,6 +684,9 @@ static int ocfs2_validate_extent_block(struct super_block *sb,
struct ocfs2_extent_block *eb =
(struct ocfs2_extent_block *)bh->b_data;

+ mlog(0, "Validating extent block %llu\n",
+ (unsigned long long)bh->b_blocknr);
+
if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
ocfs2_error(sb,
"Extent block #%llu has bad signature %.*s",
@@ -719,21 +722,13 @@ int ocfs2_read_extent_block(struct inode *inode, u64 eb_blkno,
int rc;
struct buffer_head *tmp = *bh;

- rc = ocfs2_read_block(inode, eb_blkno, &tmp);
- if (rc)
- goto out;
-
- rc = ocfs2_validate_extent_block(inode->i_sb, tmp);
- if (rc) {
- brelse(tmp);
- goto out;
- }
+ rc = ocfs2_read_block(inode, eb_blkno, &tmp,
+ ocfs2_validate_extent_block);

/* If ocfs2_read_block() got us a new bh, pass it up. */
- if (!*bh)
+ if (!rc && !*bh)
*bh = tmp;

-out:
return rc;
}

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 @@ bail:
}

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 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr,

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 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr,
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
diff --git a/fs/ocfs2/buffer_head_io.h b/fs/ocfs2/buffer_head_io.h
index 75e1dcb..c75d682 100644
--- a/fs/ocfs2/buffer_head_io.h
+++ b/fs/ocfs2/buffer_head_io.h
@@ -31,21 +31,24 @@
void ocfs2_end_buffer_io_sync(struct buffer_head *bh,
int uptodate);

-static inline int ocfs2_read_block(struct inode *inode,
- u64 off,
- struct buffer_head **bh);
-
int ocfs2_write_block(struct ocfs2_super *osb,
struct buffer_head *bh,
struct inode *inode);
-int ocfs2_read_blocks(struct inode *inode,
- u64 block,
- int nr,
- struct buffer_head *bhs[],
- int flags);
int ocfs2_read_blocks_sync(struct ocfs2_super *osb, u64 block,
unsigned int nr, struct buffer_head *bhs[]);

+/*
+ * If not NULL, validate() will be called on a buffer that is freshly
+ * read from disk. It will not be called if the buffer was in cache.
+ * Note that if validate() is being used for this buffer, it needs to
+ * be set even for a READAHEAD call, as it marks the buffer for later
+ * validation.
+ */
+int ocfs2_read_blocks(struct inode *inode, u64 block, int nr,
+ struct buffer_head *bhs[], int flags,
+ int (*validate)(struct super_block *sb,
+ struct buffer_head *bh));
+
int ocfs2_write_super_or_backup(struct ocfs2_super *osb,
struct buffer_head *bh);

@@ -53,7 +56,9 @@ int ocfs2_write_super_or_backup(struct ocfs2_super *osb,
#define OCFS2_BH_READAHEAD 8

static inline int ocfs2_read_block(struct inode *inode, u64 off,
- struct buffer_head **bh)
+ struct buffer_head **bh,
+ int (*validate)(struct super_block *sb,
+ struct buffer_head *bh))
{
int status = 0;

@@ -63,7 +68,7 @@ static inline int ocfs2_read_block(struct inode *inode, u64 off,
goto bail;
}

- status = ocfs2_read_blocks(inode, off, 1, bh, 0);
+ status = ocfs2_read_blocks(inode, off, 1, bh, 0, validate);

bail:
return status;
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index c2f3fd9..7e863d4 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -214,6 +214,8 @@ static int ocfs2_validate_dir_block(struct super_block *sb,
* Nothing yet. We don't validate dirents here, that's handled
* in-place when the code walks them.
*/
+ mlog(0, "Validating dirblock %llu\n",
+ (unsigned long long)bh->b_blocknr);

return 0;
}
@@ -255,20 +257,13 @@ static int ocfs2_read_dir_block(struct inode *inode, u64 v_block,
goto out;
}

- rc = ocfs2_read_blocks(inode, p_blkno, 1, &tmp, flags);
+ rc = ocfs2_read_blocks(inode, p_blkno, 1, &tmp, flags,
+ ocfs2_validate_dir_block);
if (rc) {
mlog_errno(rc);
goto out;
}

- if (!(flags & OCFS2_BH_READAHEAD)) {
- rc = ocfs2_validate_dir_block(inode->i_sb, tmp);
- if (rc) {
- brelse(tmp);
- goto out;
- }
- }
-
/* If ocfs2_read_blocks() got us a new bh, pass it up. */
if (!*bh)
*bh = tmp;
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 9eb701b..ec3497b 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -1255,6 +1255,9 @@ int ocfs2_validate_inode_block(struct super_block *sb,
int rc = -EINVAL;
struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;

+ mlog(0, "Validating dinode %llu\n",
+ (unsigned long long)bh->b_blocknr);
+
BUG_ON(!buffer_uptodate(bh));

if (!OCFS2_IS_VALID_DINODE(di)) {
@@ -1300,23 +1303,12 @@ int ocfs2_read_inode_block_full(struct inode *inode, struct buffer_head **bh,
struct buffer_head *tmp = *bh;

rc = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1, &tmp,
- flags);
- if (rc)
- goto out;
-
- if (!(flags & OCFS2_BH_READAHEAD)) {
- rc = ocfs2_validate_inode_block(inode->i_sb, tmp);
- if (rc) {
- brelse(tmp);
- goto out;
- }
- }
+ flags, ocfs2_validate_inode_block);

/* If ocfs2_read_blocks() got us a new bh, pass it up. */
- if (!*bh)
+ if (!rc && !*bh)
*bh = tmp;

-out:
return rc;
}

diff --git a/fs/ocfs2/resize.c b/fs/ocfs2/resize.c
index 252baff..867de3e 100644
--- a/fs/ocfs2/resize.c
+++ b/fs/ocfs2/resize.c
@@ -394,7 +394,7 @@ static int ocfs2_check_new_group(struct inode *inode,
(struct ocfs2_group_desc *)group_bh->b_data;
u16 cl_bpc = le16_to_cpu(di->id2.i_chain.cl_bpc);

- ret = ocfs2_validate_group_descriptor(inode->i_sb, di, group_bh, 1);
+ ret = ocfs2_check_group_descriptor(inode->i_sb, di, group_bh);
if (ret)
goto out;

diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index bdda2d8..40661e7 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -151,7 +151,7 @@ int ocfs2_refresh_slot_info(struct ocfs2_super *osb)
* this is not true, the read of -1 (UINT64_MAX) will fail.
*/
ret = ocfs2_read_blocks(si->si_inode, -1, si->si_blocks, si->si_bh,
- OCFS2_BH_IGNORE_CACHE);
+ OCFS2_BH_IGNORE_CACHE, NULL);
if (ret == 0) {
spin_lock(&osb->osb_lock);
ocfs2_update_slot_info(si);
@@ -405,7 +405,7 @@ static int ocfs2_map_slot_buffers(struct ocfs2_super *osb,

bh = NULL; /* Acquire a fresh bh */
status = ocfs2_read_blocks(si->si_inode, blkno, 1, &bh,
- OCFS2_BH_IGNORE_CACHE);
+ OCFS2_BH_IGNORE_CACHE, NULL);
if (status < 0) {
mlog_errno(status);
goto bail;
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 766a00b..226fe21 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -145,14 +145,6 @@ static u32 ocfs2_bits_per_group(struct ocfs2_chain_list *cl)
return (u32)le16_to_cpu(cl->cl_cpg) * (u32)le16_to_cpu(cl->cl_bpc);
}

-int ocfs2_validate_group_descriptor(struct super_block *sb,
- struct ocfs2_dinode *di,
- struct buffer_head *bh,
- int clean_error)
-{
- unsigned int max_bits;
- struct ocfs2_group_desc *gd = (struct ocfs2_group_desc *)bh->b_data;
-
#define do_error(fmt, ...) \
do{ \
if (clean_error) \
@@ -161,6 +153,12 @@ int ocfs2_validate_group_descriptor(struct super_block *sb,
ocfs2_error(sb, fmt, ##__VA_ARGS__); \
} while (0)

+static int ocfs2_validate_gd_self(struct super_block *sb,
+ struct buffer_head *bh,
+ int clean_error)
+{
+ struct ocfs2_group_desc *gd = (struct ocfs2_group_desc *)bh->b_data;
+
if (!OCFS2_IS_VALID_GROUP_DESC(gd)) {
do_error("Group descriptor #%llu has bad signature %.*s",
(unsigned long long)bh->b_blocknr, 7,
@@ -184,6 +182,35 @@ int ocfs2_validate_group_descriptor(struct super_block *sb,
return -EINVAL;
}

+ if (le16_to_cpu(gd->bg_free_bits_count) > le16_to_cpu(gd->bg_bits)) {
+ do_error("Group descriptor #%llu has bit count %u but "
+ "claims that %u are free",
+ (unsigned long long)bh->b_blocknr,
+ le16_to_cpu(gd->bg_bits),
+ le16_to_cpu(gd->bg_free_bits_count));
+ return -EINVAL;
+ }
+
+ if (le16_to_cpu(gd->bg_bits) > (8 * le16_to_cpu(gd->bg_size))) {
+ do_error("Group descriptor #%llu has bit count %u but "
+ "max bitmap bits of %u",
+ (unsigned long long)bh->b_blocknr,
+ le16_to_cpu(gd->bg_bits),
+ 8 * le16_to_cpu(gd->bg_size));
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int ocfs2_validate_gd_parent(struct super_block *sb,
+ struct ocfs2_dinode *di,
+ struct buffer_head *bh,
+ int clean_error)
+{
+ unsigned int max_bits;
+ struct ocfs2_group_desc *gd = (struct ocfs2_group_desc *)bh->b_data;
+
if (di->i_blkno != gd->bg_parent_dinode) {
do_error("Group descriptor #%llu has bad parent "
"pointer (%llu, expected %llu)",
@@ -209,26 +236,35 @@ int ocfs2_validate_group_descriptor(struct super_block *sb,
return -EINVAL;
}

- if (le16_to_cpu(gd->bg_free_bits_count) > le16_to_cpu(gd->bg_bits)) {
- do_error("Group descriptor #%llu has bit count %u but "
- "claims that %u are free",
- (unsigned long long)bh->b_blocknr,
- le16_to_cpu(gd->bg_bits),
- le16_to_cpu(gd->bg_free_bits_count));
- return -EINVAL;
- }
+ return 0;
+}

- if (le16_to_cpu(gd->bg_bits) > (8 * le16_to_cpu(gd->bg_size))) {
- do_error("Group descriptor #%llu has bit count %u but "
- "max bitmap bits of %u",
- (unsigned long long)bh->b_blocknr,
- le16_to_cpu(gd->bg_bits),
- 8 * le16_to_cpu(gd->bg_size));
- return -EINVAL;
- }
#undef do_error

- return 0;
+/*
+ * This version only prints errors. It does not fail the filesystem, and
+ * exists only for resize.
+ */
+int ocfs2_check_group_descriptor(struct super_block *sb,
+ struct ocfs2_dinode *di,
+ struct buffer_head *bh)
+{
+ int rc;
+
+ rc = ocfs2_validate_gd_self(sb, bh, 1);
+ if (!rc)
+ rc = ocfs2_validate_gd_parent(sb, di, bh, 1);
+
+ return rc;
+}
+
+static int ocfs2_validate_group_descriptor(struct super_block *sb,
+ struct buffer_head *bh)
+{
+ mlog(0, "Validating group descriptor %llu\n",
+ (unsigned long long)bh->b_blocknr);
+
+ return ocfs2_validate_gd_self(sb, bh, 0);
}

int ocfs2_read_group_descriptor(struct inode *inode, struct ocfs2_dinode *di,
@@ -237,11 +273,12 @@ int ocfs2_read_group_descriptor(struct inode *inode, struct ocfs2_dinode *di,
int rc;
struct buffer_head *tmp = *bh;

- rc = ocfs2_read_block(inode, gd_blkno, &tmp);
+ rc = ocfs2_read_block(inode, gd_blkno, &tmp,
+ ocfs2_validate_group_descriptor);
if (rc)
goto out;

- rc = ocfs2_validate_group_descriptor(inode->i_sb, di, tmp, 0);
+ rc = ocfs2_validate_gd_parent(inode->i_sb, di, tmp, 0);
if (rc) {
brelse(tmp);
goto out;
diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index 43de4fd..e3c13c7 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -165,16 +165,15 @@ void ocfs2_free_ac_resource(struct ocfs2_alloc_context *ac);
u64 ocfs2_which_cluster_group(struct inode *inode, u32 cluster);

/*
- * By default, ocfs2_validate_group_descriptor() calls ocfs2_error() when it
+ * By default, ocfs2_read_group_descriptor() calls ocfs2_error() when it
* finds a problem. A caller that wants to check a group descriptor
- * without going readonly passes a nonzero clean_error. This is only
- * resize, really. Everyone else should be using
- * ocfs2_read_group_descriptor().
+ * without going readonly should read the block with ocfs2_read_block[s]()
+ * and then checking it with this function. This is only resize, really.
+ * Everyone else should be using ocfs2_read_group_descriptor().
*/
-int ocfs2_validate_group_descriptor(struct super_block *sb,
- struct ocfs2_dinode *di,
- struct buffer_head *bh,
- int clean_error);
+int ocfs2_check_group_descriptor(struct super_block *sb,
+ struct ocfs2_dinode *di,
+ struct buffer_head *bh);
/*
* Read a group descriptor block into *bh. If *bh is NULL, a bh will be
* allocated. This is a cached read. The descriptor will be validated with
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index ef4aa54..8af29b3 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -266,7 +266,8 @@ static int ocfs2_read_xattr_bucket(struct ocfs2_xattr_bucket *bucket,
int rc;

rc = ocfs2_read_blocks(bucket->bu_inode, xb_blkno,
- bucket->bu_blocks, bucket->bu_bhs, 0);
+ bucket->bu_blocks, bucket->bu_bhs, 0,
+ NULL);
if (rc)
ocfs2_xattr_bucket_relse(bucket);
return rc;
@@ -359,12 +360,8 @@ static int ocfs2_read_xattr_block(struct inode *inode, u64 xb_blkno,
int rc;
struct buffer_head *tmp = *bh;

- rc = ocfs2_read_block(inode, xb_blkno, &tmp);
- if (!rc) {
- rc = ocfs2_validate_xattr_block(inode->i_sb, tmp);
- if (rc)
- brelse(tmp);
- }
+ rc = ocfs2_read_block(inode, xb_blkno, &tmp,
+ ocfs2_validate_xattr_block);

/* If ocfs2_read_block() got us a new bh, pass it up. */
if (!rc && !*bh)
@@ -925,7 +922,7 @@ static int ocfs2_xattr_get_value_outside(struct inode *inode,
blkno = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
/* Copy ocfs2_xattr_value */
for (i = 0; i < num_clusters * bpc; i++, blkno++) {
- ret = ocfs2_read_block(inode, blkno, &bh);
+ ret = ocfs2_read_block(inode, blkno, &bh, NULL);
if (ret) {
mlog_errno(ret);
goto out;
@@ -1174,7 +1171,7 @@ static int __ocfs2_xattr_set_value_outside(struct inode *inode,
blkno = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);

for (i = 0; i < num_clusters * bpc; i++, blkno++) {
- ret = ocfs2_read_block(inode, blkno, &bh);
+ ret = ocfs2_read_block(inode, blkno, &bh, NULL);
if (ret) {
mlog_errno(ret);
goto out;
@@ -2206,7 +2203,7 @@ static int ocfs2_calc_xattr_set_need(struct inode *inode,
base = xis->base;
credits += OCFS2_INODE_UPDATE_CREDITS;
} else {
- int i, block_off;
+ int i, block_off = 0;
xb = (struct ocfs2_xattr_block *)xbs->xattr_bh->b_data;
xe = xbs->here;
name_offset = le16_to_cpu(xe->xe_name_offset);
@@ -2840,6 +2837,7 @@ static int ocfs2_find_xe_in_bucket(struct inode *inode,
break;
}

+
xe_name = bucket_block(bucket, block_off) + new_offset;
if (!memcmp(name, xe_name, name_len)) {
*xe_index = i;
@@ -3598,7 +3596,7 @@ static int ocfs2_mv_xattr_bucket_cross_cluster(struct inode *inode,
goto out;
}

- ret = ocfs2_read_block(inode, prev_blkno, &old_bh);
+ ret = ocfs2_read_block(inode, prev_blkno, &old_bh, NULL);
if (ret < 0) {
mlog_errno(ret);
brelse(new_bh);
@@ -3990,7 +3988,7 @@ static int ocfs2_cp_xattr_cluster(struct inode *inode,
ocfs2_journal_dirty(handle, first_bh);

/* update the new bucket header. */
- ret = ocfs2_read_block(inode, to_blk_start, &bh);
+ ret = ocfs2_read_block(inode, to_blk_start, &bh, NULL);
if (ret < 0) {
mlog_errno(ret);
goto out;
@@ -4337,7 +4335,7 @@ static int ocfs2_add_new_xattr_bucket(struct inode *inode,
goto out;
}

- ret = ocfs2_read_block(inode, p_blkno, &first_bh);
+ ret = ocfs2_read_block(inode, p_blkno, &first_bh, NULL);
if (ret) {
mlog_errno(ret);
goto out;
@@ -4635,7 +4633,7 @@ static int ocfs2_xattr_bucket_value_truncate(struct inode *inode,
BUG_ON(value_blk != (offset + OCFS2_XATTR_ROOT_SIZE - 1) / blocksize);
value_blk += header_bh->b_blocknr;

- ret = ocfs2_read_block(inode, value_blk, &value_bh);
+ ret = ocfs2_read_block(inode, value_blk, &value_bh, NULL);
if (ret) {
mlog_errno(ret);
goto out;
--
1.5.6

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