Skip to content

Commit

Permalink
ocfs2: Wrap group descriptor reads in a dedicated function.
Browse files Browse the repository at this point in the history 
We have a clean call for validating group descriptors, but every place
that wants the always does a read_block()+validate() call pair.  Create
a toplevel ocfs2_read_group_descriptor() that does the right
thing.  This allows us to leverage the single call point later for
fancier handling.  We also add validation of gd->bg_generation against
the superblock and gd->bg_blkno against the block we thought we read.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
  • Loading branch information
Joel Becker authored and Mark Fasheh committed Jan 5, 2009
1 parent 57e3e79 commit 68f64d4
Show file tree
Hide file tree
Showing 3 changed files with 78 additions and 61 deletions.
12 changes: 3 additions & 9 deletions fs/ocfs2/resize.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -330,20 +330,14 @@ int ocfs2_group_extend(struct inode * inode, int new_clusters)
lgd_blkno = ocfs2_which_cluster_group(main_bm_inode,
first_new_cluster - 1);

ret = ocfs2_read_block(main_bm_inode, lgd_blkno, &group_bh);
ret = ocfs2_read_group_descriptor(main_bm_inode, fe, lgd_blkno,
&group_bh);
if (ret < 0) {
mlog_errno(ret);
goto out_unlock;
}

group = (struct ocfs2_group_desc *)group_bh->b_data;

ret = ocfs2_check_group_descriptor(inode->i_sb, fe, group);
if (ret) {
mlog_errno(ret);
goto out_unlock;
}

cl_bpc = le16_to_cpu(fe->id2.i_chain.cl_bpc);
if (le16_to_cpu(group->bg_bits) / cl_bpc + new_clusters >
le16_to_cpu(fe->id2.i_chain.cl_cpg)) {
Expand Down Expand Up @@ -400,7 +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, gd, 1);
ret = ocfs2_validate_group_descriptor(inode->i_sb, di, group_bh, 1);
if (ret)
goto out;

Expand Down
108 changes: 65 additions & 43 deletions fs/ocfs2/suballoc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -145,13 +145,13 @@ 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);
}

/* somewhat more expensive than our other checks, so use sparingly. */
int ocfs2_validate_group_descriptor(struct super_block *sb,
struct ocfs2_dinode *di,
struct ocfs2_group_desc *gd,
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{ \
Expand All @@ -162,50 +162,66 @@ int ocfs2_validate_group_descriptor(struct super_block *sb,
} while (0)

if (!OCFS2_IS_VALID_GROUP_DESC(gd)) {
do_error("Group Descriptor #%llu has bad signature %.*s",
(unsigned long long)le64_to_cpu(gd->bg_blkno), 7,
do_error("Group descriptor #%llu has bad signature %.*s",
(unsigned long long)bh->b_blocknr, 7,
gd->bg_signature);
return -EINVAL;
}

if (le64_to_cpu(gd->bg_blkno) != bh->b_blocknr) {
do_error("Group descriptor #%llu has an invalid bg_blkno "
"of %llu",
(unsigned long long)bh->b_blocknr,
(unsigned long long)le64_to_cpu(gd->bg_blkno));
return -EINVAL;
}

if (le32_to_cpu(gd->bg_generation) != OCFS2_SB(sb)->fs_generation) {
do_error("Group descriptor #%llu has an invalid "
"fs_generation of #%u",
(unsigned long long)bh->b_blocknr,
le32_to_cpu(gd->bg_generation));
return -EINVAL;
}

if (di->i_blkno != gd->bg_parent_dinode) {
do_error("Group descriptor # %llu has bad parent "
do_error("Group descriptor #%llu has bad parent "
"pointer (%llu, expected %llu)",
(unsigned long long)le64_to_cpu(gd->bg_blkno),
(unsigned long long)bh->b_blocknr,
(unsigned long long)le64_to_cpu(gd->bg_parent_dinode),
(unsigned long long)le64_to_cpu(di->i_blkno));
return -EINVAL;
}

max_bits = le16_to_cpu(di->id2.i_chain.cl_cpg) * le16_to_cpu(di->id2.i_chain.cl_bpc);
if (le16_to_cpu(gd->bg_bits) > max_bits) {
do_error("Group descriptor # %llu has bit count of %u",
(unsigned long long)le64_to_cpu(gd->bg_blkno),
do_error("Group descriptor #%llu has bit count of %u",
(unsigned long long)bh->b_blocknr,
le16_to_cpu(gd->bg_bits));
return -EINVAL;
}

if (le16_to_cpu(gd->bg_chain) >=
le16_to_cpu(di->id2.i_chain.cl_next_free_rec)) {
do_error("Group descriptor # %llu has bad chain %u",
(unsigned long long)le64_to_cpu(gd->bg_blkno),
do_error("Group descriptor #%llu has bad chain %u",
(unsigned long long)bh->b_blocknr,
le16_to_cpu(gd->bg_chain));
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 "
do_error("Group descriptor #%llu has bit count %u but "
"claims that %u are free",
(unsigned long long)le64_to_cpu(gd->bg_blkno),
(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 "
do_error("Group descriptor #%llu has bit count %u but "
"max bitmap bits of %u",
(unsigned long long)le64_to_cpu(gd->bg_blkno),
(unsigned long long)bh->b_blocknr,
le16_to_cpu(gd->bg_bits),
8 * le16_to_cpu(gd->bg_size));
return -EINVAL;
Expand All @@ -215,6 +231,30 @@ int ocfs2_validate_group_descriptor(struct super_block *sb,
return 0;
}

int ocfs2_read_group_descriptor(struct inode *inode, struct ocfs2_dinode *di,
u64 gd_blkno, struct buffer_head **bh)
{
int rc;
struct buffer_head *tmp = *bh;

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

rc = ocfs2_validate_group_descriptor(inode->i_sb, di, tmp, 0);
if (rc) {
brelse(tmp);
goto out;
}

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

out:
return rc;
}

static int ocfs2_block_group_fill(handle_t *handle,
struct inode *alloc_inode,
struct buffer_head *bg_bh,
Expand Down Expand Up @@ -1177,21 +1217,17 @@ static int ocfs2_search_one_group(struct ocfs2_alloc_context *ac,
u16 found;
struct buffer_head *group_bh = NULL;
struct ocfs2_group_desc *gd;
struct ocfs2_dinode *di = (struct ocfs2_dinode *)ac->ac_bh->b_data;
struct inode *alloc_inode = ac->ac_inode;

ret = ocfs2_read_block(alloc_inode, gd_blkno, &group_bh);
ret = ocfs2_read_group_descriptor(alloc_inode, di, gd_blkno,
&group_bh);
if (ret < 0) {
mlog_errno(ret);
return ret;
}

gd = (struct ocfs2_group_desc *) group_bh->b_data;
if (!OCFS2_IS_VALID_GROUP_DESC(gd)) {
OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, gd);
ret = -EIO;
goto out;
}

ret = ac->ac_group_search(alloc_inode, group_bh, bits_wanted, min_bits,
ac->ac_max_block, bit_off, &found);
if (ret < 0) {
Expand Down Expand Up @@ -1248,19 +1284,14 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
bits_wanted, chain,
(unsigned long long)OCFS2_I(alloc_inode)->ip_blkno);

status = ocfs2_read_block(alloc_inode,
le64_to_cpu(cl->cl_recs[chain].c_blkno),
&group_bh);
status = ocfs2_read_group_descriptor(alloc_inode, fe,
le64_to_cpu(cl->cl_recs[chain].c_blkno),
&group_bh);
if (status < 0) {
mlog_errno(status);
goto bail;
}
bg = (struct ocfs2_group_desc *) group_bh->b_data;
status = ocfs2_check_group_descriptor(alloc_inode->i_sb, fe, bg);
if (status) {
mlog_errno(status);
goto bail;
}

status = -ENOSPC;
/* for now, the chain search is a bit simplistic. We just use
Expand All @@ -1278,18 +1309,13 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
next_group = le64_to_cpu(bg->bg_next_group);
prev_group_bh = group_bh;
group_bh = NULL;
status = ocfs2_read_block(alloc_inode,
next_group, &group_bh);
status = ocfs2_read_group_descriptor(alloc_inode, fe,
next_group, &group_bh);
if (status < 0) {
mlog_errno(status);
goto bail;
}
bg = (struct ocfs2_group_desc *) group_bh->b_data;
status = ocfs2_check_group_descriptor(alloc_inode->i_sb, fe, bg);
if (status) {
mlog_errno(status);
goto bail;
}
}
if (status < 0) {
if (status != -ENOSPC)
Expand Down Expand Up @@ -1801,18 +1827,14 @@ int ocfs2_free_suballoc_bits(handle_t *handle,
(unsigned long long)OCFS2_I(alloc_inode)->ip_blkno, count,
(unsigned long long)bg_blkno, start_bit);

status = ocfs2_read_block(alloc_inode, bg_blkno, &group_bh);
status = ocfs2_read_group_descriptor(alloc_inode, fe, bg_blkno,
&group_bh);
if (status < 0) {
mlog_errno(status);
goto bail;
}

group = (struct ocfs2_group_desc *) group_bh->b_data;
status = ocfs2_check_group_descriptor(alloc_inode->i_sb, fe, group);
if (status) {
mlog_errno(status);
goto bail;
}

BUG_ON((count + start_bit) > le16_to_cpu(group->bg_bits));

status = ocfs2_block_group_clear_bits(handle, alloc_inode,
Expand Down
19 changes: 10 additions & 9 deletions fs/ocfs2/suballoc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -164,23 +164,24 @@ void ocfs2_free_ac_resource(struct ocfs2_alloc_context *ac);
* and return that block offset. */
u64 ocfs2_which_cluster_group(struct inode *inode, u32 cluster);

/* somewhat more expensive than our other checks, so use sparingly. */
/*
* By default, ocfs2_validate_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.
* 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 ocfs2_group_desc *gd,
struct buffer_head *bh,
int clean_error);
static inline int ocfs2_check_group_descriptor(struct super_block *sb,
struct ocfs2_dinode *di,
struct ocfs2_group_desc *gd)
{
return ocfs2_validate_group_descriptor(sb, di, gd, 0);
}
/*
* 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
* ocfs2_validate_group_descriptor().
*/
int ocfs2_read_group_descriptor(struct inode *inode, struct ocfs2_dinode *di,
u64 gd_blkno, struct buffer_head **bh);

int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_extent_tree *et,
u32 clusters_to_add, u32 extents_to_split,
Expand Down

0 comments on commit 68f64d4

Please sign in to comment.