[GFS2] Shrink & rename di_depth

This patch forms a pair with the previous patch which shrunk
di_height. Like that patch di_depth is renamed i_depth and moved
into struct gfs2_inode directly. Also the field goes from 16 bits
to 8 bits since it is also limited to a max value which is rather
small (17 in this case). In addition we also now validate the field
against this maximum value when its read in.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

3 files changed, 25 insertions, 22 deletions

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 78c236fb34ec..081daa96a9d9 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -757,7 +757,7 @@ static struct gfs2_dirent *gfs2_dirent_search(struct inode *inode,
 
         if (ip->i_di.di_flags & GFS2_DIF_EXHASH) {
                 struct gfs2_leaf *leaf;
-                unsigned hsize = 1 << ip->i_di.di_depth;
+                unsigned hsize = 1 << ip->i_depth;
                 unsigned index;
                 u64 ln;
                 if (hsize * sizeof(u64) != ip->i_di.di_size) {
@@ -765,7 +765,7 @@ static struct gfs2_dirent *gfs2_dirent_search(struct inode *inode,
                         return ERR_PTR(-EIO);
                 }
 
-                index = name->hash >> (32 - ip->i_di.di_depth);
+                index = name->hash >> (32 - ip->i_depth);
                 error = get_first_leaf(ip, index, &bh);
                 if (error)
                         return ERR_PTR(error);
@@ -910,7 +910,7 @@ static int dir_make_exhash(struct inode *inode)
         dip->i_di.di_flags |= GFS2_DIF_EXHASH;
 
         for (x = sdp->sd_hash_ptrs, y = -1; x; x >>= 1, y++) ;
-        dip->i_di.di_depth = y;
+        dip->i_depth = y;
 
         gfs2_dinode_out(dip, dibh->b_data);
 
@@ -941,7 +941,7 @@ static int dir_split_leaf(struct inode *inode, const struct qstr *name)
         int x, moved = 0;
         int error;
 
-        index = name->hash >> (32 - dip->i_di.di_depth);
+        index = name->hash >> (32 - dip->i_depth);
         error = get_leaf_nr(dip, index, &leaf_no);
         if (error)
                 return error;
@@ -952,7 +952,7 @@ static int dir_split_leaf(struct inode *inode, const struct qstr *name)
                 return error;
 
         oleaf = (struct gfs2_leaf *)obh->b_data;
-        if (dip->i_di.di_depth == be16_to_cpu(oleaf->lf_depth)) {
+        if (dip->i_depth == be16_to_cpu(oleaf->lf_depth)) {
                 brelse(obh);
                 return 1; /* can't split */
         }
@@ -967,10 +967,10 @@ static int dir_split_leaf(struct inode *inode, const struct qstr *name)
         bn = nbh->b_blocknr;
 
         /*  Compute the start and len of leaf pointers in the hash table.  */
-        len = 1 << (dip->i_di.di_depth - be16_to_cpu(oleaf->lf_depth));
+        len = 1 << (dip->i_depth - be16_to_cpu(oleaf->lf_depth));
         half_len = len >> 1;
         if (!half_len) {
-                printk(KERN_WARNING "di_depth %u lf_depth %u index %u\n", dip->i_di.di_depth, be16_to_cpu(oleaf->lf_depth), index);
+                printk(KERN_WARNING "i_depth %u lf_depth %u index %u\n", dip->i_depth, be16_to_cpu(oleaf->lf_depth), index);
                 gfs2_consist_inode(dip);
                 error = -EIO;
                 goto fail_brelse;
@@ -997,7 +997,7 @@ static int dir_split_leaf(struct inode *inode, const struct qstr *name)
         kfree(lp);
 
         /*  Compute the divider  */
-        divider = (start + half_len) << (32 - dip->i_di.di_depth);
+        divider = (start + half_len) << (32 - dip->i_depth);
 
         /*  Copy the entries  */
         dirent_first(dip, obh, &dent);
@@ -1082,7 +1082,7 @@ static int dir_double_exhash(struct gfs2_inode *dip)
         int x;
         int error = 0;
 
-        hsize = 1 << dip->i_di.di_depth;
+        hsize = 1 << dip->i_depth;
         if (hsize * sizeof(u64) != dip->i_di.di_size) {
                 gfs2_consist_inode(dip);
                 return -EIO;
@@ -1125,7 +1125,7 @@ static int dir_double_exhash(struct gfs2_inode *dip)
 
         error = gfs2_meta_inode_buffer(dip, &dibh);
         if (!gfs2_assert_withdraw(sdp, !error)) {
-                dip->i_di.di_depth++;
+                dip->i_depth++;
                 gfs2_dinode_out(dip, dibh->b_data);
                 brelse(dibh);
         }
@@ -1370,14 +1370,14 @@ static int dir_e_read(struct inode *inode, u64 *offset, void *opaque,
         int error = 0;
         unsigned depth = 0;
 
-        hsize = 1 << dip->i_di.di_depth;
+        hsize = 1 << dip->i_depth;
         if (hsize * sizeof(u64) != dip->i_di.di_size) {
                 gfs2_consist_inode(dip);
                 return -EIO;
         }
 
         hash = gfs2_dir_offset2hash(*offset);
-        index = hash >> (32 - dip->i_di.di_depth);
+        index = hash >> (32 - dip->i_depth);
 
         lp = kmalloc(sdp->sd_hash_bsize, GFP_KERNEL);
         if (!lp)
@@ -1405,7 +1405,7 @@ static int dir_e_read(struct inode *inode, u64 *offset, void *opaque,
                 if (error)
                         break;
 
-                len = 1 << (dip->i_di.di_depth - depth);
+                len = 1 << (dip->i_depth - depth);
                 index = (index & ~(len - 1)) + len;
         }
 
@@ -1549,7 +1549,7 @@ static int dir_new_leaf(struct inode *inode, const struct qstr *name)
         u32 index;
         u64 bn;
 
-        index = name->hash >> (32 - ip->i_di.di_depth);
+        index = name->hash >> (32 - ip->i_depth);
         error = get_first_leaf(ip, index, &obh);
         if (error)
                 return error;
@@ -1641,7 +1641,7 @@ int gfs2_dir_add(struct inode *inode, const struct qstr *name,
                         continue;
                 if (error < 0)
                         break;
-                if (ip->i_di.di_depth < GFS2_DIR_MAX_DEPTH) {
+                if (ip->i_depth < GFS2_DIR_MAX_DEPTH) {
                         error = dir_double_exhash(ip);
                         if (error)
                                 break;
@@ -1785,7 +1785,7 @@ static int foreach_leaf(struct gfs2_inode *dip, leaf_call_t lc, void *data)
         u64 leaf_no;
         int error = 0;
 
-        hsize = 1 << dip->i_di.di_depth;
+        hsize = 1 << dip->i_depth;
         if (hsize * sizeof(u64) != dip->i_di.di_size) {
                 gfs2_consist_inode(dip);
                 return -EIO;
@@ -1817,7 +1817,7 @@ static int foreach_leaf(struct gfs2_inode *dip, leaf_call_t lc, void *data)
                         if (error)
                                 goto out;
                         leaf = (struct gfs2_leaf *)bh->b_data;
-                        len = 1 << (dip->i_di.di_depth - be16_to_cpu(leaf->lf_depth));
+                        len = 1 << (dip->i_depth - be16_to_cpu(leaf->lf_depth));
                         brelse(bh);
 
                         error = lc(dip, index, len, leaf_no, data);
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index e9c58dc76869..9dfdde3612a4 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -246,7 +246,6 @@ struct gfs2_dinode_host {
         u64 di_generation;      /* generation number for NFS */
         u32 di_flags;           /* GFS2_DIF_... */
         /* These only apply to directories  */
-        u16 di_depth;           /* Number of bits in the table */
         u32 di_entries;         /* The number of entries in the directory */
         u64 di_eattr;           /* extended attribute block number */
 };
@@ -267,6 +266,7 @@ struct gfs2_inode {
 
         struct rw_semaphore i_rw_mutex;
         u8 i_height;
+        u8 i_depth;
 };
 
 /*
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index db5961a9aa59..65fdfee9ca9b 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -248,7 +248,7 @@ static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
 {
         struct gfs2_dinode_host *di = &ip->i_di;
         const struct gfs2_dinode *str = buf;
-        u16 height;
+        u16 height, depth;
 
         if (unlikely(ip->i_no_addr != be64_to_cpu(str->di_num.no_addr)))
                 goto corrupt;
@@ -293,7 +293,10 @@ static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
                 goto corrupt;
         ip->i_height = (u8)height;
 
-        di->di_depth = be16_to_cpu(str->di_depth);
+        depth = be16_to_cpu(str->di_depth);
+        if (unlikely(depth > GFS2_DIR_MAX_DEPTH))
+                goto corrupt;
+        ip->i_depth = (u8)depth;
         di->di_entries = be32_to_cpu(str->di_entries);
 
         di->di_eattr = be64_to_cpu(str->di_eattr);
@@ -1410,7 +1413,7 @@ void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf)
         str->di_payload_format = cpu_to_be32(S_ISDIR(ip->i_inode.i_mode) &&
                                              !(ip->i_di.di_flags & GFS2_DIF_EXHASH) ?
                                              GFS2_FORMAT_DE : 0);
-        str->di_depth = cpu_to_be16(di->di_depth);
+        str->di_depth = cpu_to_be16(ip->i_depth);
         str->di_entries = cpu_to_be32(di->di_entries);
 
         str->di_eattr = cpu_to_be64(di->di_eattr);
@@ -1436,7 +1439,7 @@ void gfs2_dinode_print(const struct gfs2_inode *ip)
                (unsigned long long)di->di_goal_data);
         printk(KERN_INFO "  di_flags = 0x%.8X\n", di->di_flags);
         printk(KERN_INFO "  i_height = %u\n", ip->i_height);
-        printk(KERN_INFO "  di_depth = %u\n", di->di_depth);
+        printk(KERN_INFO "  i_depth = %u\n", ip->i_depth);
         printk(KERN_INFO "  di_entries = %u\n", di->di_entries);
         printk(KERN_INFO "  di_eattr = %llu\n",
                (unsigned long long)di->di_eattr);