[PATCH] befs : Add small_data support through xattr handlers (v2)

[Fabian Frederick]

Beos Filesystem stores small attributes in first inode block automagically read during lookup.
Current driver implementation does nothing about it.

Those attributes feature both window manager and user metadata.

-This patch wakes up the small_data dump functionality when mounting in debug mode (iget)
-The same is done "for real" by creating a list_head merged in befs_inode_info.
-getfattr -n "attributename" is handled as well to retrieve small attributes
 through xattr_handlers.

I hope someone can help me improve that feature despite that driver is declared "Orphan" in maintainer list.

Signed off by Fabian Frederick

diff --git a/fs/befs/befs.h b/fs/befs/befs.h
index b266428..02eb7ae 100644
--- a/fs/befs/befs.h
+++ b/fs/befs/befs.h
@@ -57,6 +57,14 @@ typedef struct befs_sb_info {
 
 } befs_sb_info;
 
+typedef struct befs_small_datamem {
+	u32 type;
+	char name[BEFS_ATTRIBUTE_LEN];
+	char value[BEFS_ATTRIBUTE_VALUE_LEN];		
+	struct list_head list;
+
+} befs_small_datamem;
+
 typedef struct befs_inode_info {
 	u32 i_flags;
 	u32 i_type;
@@ -71,6 +79,7 @@ typedef struct befs_inode_info {
 	} i_data;
 
 	struct inode vfs_inode;
+	struct befs_small_datamem datamem;
 
 } befs_inode_info;
 
@@ -96,6 +105,8 @@ void befs_dump_super_block(const struct super_block *sb, befs_super_block *);
 void befs_dump_inode(const struct super_block *sb, befs_inode *);
 void befs_dump_index_entry(const struct super_block *sb, befs_disk_btree_super *);
 void befs_dump_index_node(const struct super_block *sb, befs_btree_nodehead *);
+void befs_dump_small_data(const struct super_block *sb, befs_small_data * sd);
+
 /****************************/
 
 
diff --git a/fs/befs/befs_fs_types.h b/fs/befs/befs_fs_types.h
index eb557d9..47e2ac0 100644
--- a/fs/befs/befs_fs_types.h
+++ b/fs/befs/befs_fs_types.h
@@ -26,6 +26,8 @@
 
 #define BEFS_NAME_LEN 255
 
+#define BEFS_ATTRIBUTE_LEN 255
+#define BEFS_ATTRIBUTE_VALUE_LEN 1024
 #define BEFS_SYMLINK_LEN 144
 #define BEFS_NUM_DIRECT_BLOCKS 12
 #define B_OS_NAME_LENGTH 32
diff --git a/fs/befs/debug.c b/fs/befs/debug.c
index 622e737..d23dda2 100644
--- a/fs/befs/debug.c
+++ b/fs/befs/debug.c
@@ -222,13 +222,38 @@ befs_dump_super_block(const struct super_block *sb, befs_super_block * sup)
 #endif				//CONFIG_BEFS_DEBUG
 }
 
-#if 0
-/* unused */
 void
 befs_dump_small_data(const struct super_block *sb, befs_small_data * sd)
 {
+#ifdef CONFIG_BEFS_DEBUG
+
+	char *oft, *ioft;
+	ioft=(char*)sd;
+	
+	while(1){
+		befs_debug(sb, "befs_small_data information");
+		befs_debug(sb, "   type : %x", sd->type);
+		befs_debug(sb, "   name size : %d", sd->name_size);
+		befs_debug(sb, "   name size : %d", sd->data_size);
+		if(sd->name[0]==0x13)
+			befs_debug(sb, "   name : %d", sd->data_size);
+	   	   else befs_debug(sb, "   name : %s", sd->name);
+		oft=sd->name;
+		while(oft[0])oft++; //eos
+		oft+=3; //padding
+		befs_debug(sb, "   value :%s", oft);
+		oft=oft+(sd->data_size);
+		while(!oft[0])oft++; 
+		sd=(befs_small_data*)oft;
+		befs_debug(sb, "   ioft : %x oft : %x delta : %x", ioft, oft, oft-ioft);
+		if(oft-ioft > sb->s_blocksize-sizeof(befs_inode))
+			break;
+	}
+
+#endif				//CONFIG_BEFS_DEBUG
 }
 
+#if 0
 /* unused */
 void
 befs_dump_run(const struct super_block *sb, befs_disk_block_run run)
diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
index daa15d6..ba7d3e8 100644
--- a/fs/befs/linuxvfs.c
+++ b/fs/befs/linuxvfs.c
@@ -3,6 +3,8 @@
  *
  * Copyright (C) 2001 Will Dyson <will_dyson@xxxxxxxxx
  *
+ * 12/2013 : Fabian Frederick : Adding xattr support.
+ *
  */
 
 #include <linux/module.h>
@@ -16,6 +18,7 @@
 #include <linux/parser.h>
 #include <linux/namei.h>
 #include <linux/sched.h>
+#include <linux/xattr.h>
 
 #include "befs.h"
 #include "btree.h"
@@ -36,6 +39,7 @@ static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
 static int befs_readpage(struct file *file, struct page *page);
 static sector_t befs_bmap(struct address_space *mapping, sector_t block);
 static struct dentry *befs_lookup(struct inode *, struct dentry *, unsigned int);
+static void befs_getsmalldata(struct super_block *, befs_small_data *, struct befs_small_datamem *);
 static struct inode *befs_iget(struct super_block *, unsigned long);
 static struct inode *befs_alloc_inode(struct super_block *sb);
 static void befs_destroy_inode(struct inode *inode);
@@ -43,6 +47,7 @@ static int befs_init_inodecache(void);
 static void befs_destroy_inodecache(void);
 static void *befs_follow_link(struct dentry *, struct nameidata *);
 static void *befs_fast_follow_link(struct dentry *, struct nameidata *);
+static int befs_xattr_get(struct dentry *, const char *, void *, size_t, int);
 static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
 			char **out, int *out_len);
 static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
@@ -74,6 +79,10 @@ static const struct inode_operations befs_dir_inode_operations = {
 	.lookup		= befs_lookup,
 };
 
+static const struct inode_operations befs_file_inode_operations = {
+	.getxattr	= generic_getxattr,
+};
+
 static const struct address_space_operations befs_aops = {
 	.readpage	= befs_readpage,
 	.bmap		= befs_bmap,
@@ -90,6 +99,16 @@ static const struct inode_operations befs_symlink_inode_operations = {
 	.put_link	= kfree_put_link,
 };
 
+static const struct xattr_handler befs_xattr_handler = {
+	.prefix		= "",
+	.get		= befs_xattr_get,
+};
+
+static const struct xattr_handler *befs_xattr_handlers[] = {
+	&befs_xattr_handler,
+	NULL
+};
+
 /* 
  * Called by generic_file_read() to read a page of data
  * 
@@ -311,6 +330,35 @@ static void init_once(void *foo)
 	inode_init_once(&bi->vfs_inode);
 }
 
+static void befs_getsmalldata(struct super_block *sb, befs_small_data *sd, struct befs_small_datamem *datamem)
+{
+	char *oft, *ioft;
+	struct befs_small_datamem *newdatamem;
+	struct befs_small_datamem *testdatamem;
+
+	ioft = (char*) sd;
+
+	INIT_LIST_HEAD(&datamem->list);
+
+	while(1){
+		newdatamem = kmalloc(sizeof(*newdatamem), GFP_KERNEL);
+		newdatamem->type=sd->type;
+		strcpy(newdatamem->name, sd->name);
+		oft = sd->name;
+		while(oft[0])oft++;
+		oft+=3; //padding
+		strcpy(newdatamem->value, oft);
+		INIT_LIST_HEAD(&newdatamem->list);
+		oft = oft+(sd->data_size);
+		while(!oft[0])oft++;
+		sd = oft;
+		list_add_tail(&(newdatamem->list), &(datamem->list));
+		if(oft-ioft > sb->s_blocksize-sizeof(befs_inode))
+			break;
+	}
+
+}
+
 static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
 {
 	struct buffer_head *bh = NULL;
@@ -411,7 +459,10 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
 	inode->i_mapping->a_ops = &befs_aops;
 
 	if (S_ISREG(inode->i_mode)) {
+		inode->i_op = &befs_file_inode_operations;
 		inode->i_fop = &generic_ro_fops;
+		befs_dump_small_data(sb, raw_inode->small_data);
+		befs_getsmalldata(sb,raw_inode->small_data, &(befs_ino->datamem));
 	} else if (S_ISDIR(inode->i_mode)) {
 		inode->i_op = &befs_dir_inode_operations;
 		inode->i_fop = &befs_dir_operations;
@@ -521,6 +572,42 @@ befs_fast_follow_link(struct dentry *dentry, struct nameidata *nd)
 	return NULL;
 }
 
+static int
+befs_xattr_get(struct dentry *dentry, const char *name, 
+	void *buffer, size_t buffer_size, int type)
+{
+
+
+	struct befs_small_datamem *currentdatamem;
+	struct befs_small_datamem *datamem;
+	befs_inode_info *befs_ino = NULL;
+	int name_len, error;
+
+	if (name == NULL)
+		return -EINVAL;
+
+	name_len = strlen(name);
+	if(name_len > BEFS_ATTRIBUTE_LEN)
+		return -ERANGE;
+	error = -ENODATA;
+	
+	befs_ino = BEFS_I(dentry->d_inode);
+	datamem=&(befs_ino->datamem);
+
+	list_for_each_entry(currentdatamem, &(datamem->list), list){
+		if(!strcmp(currentdatamem->name, name)){
+			if(buffer){
+				if(strlen(currentdatamem->value)<=buffer_size){
+					strcpy(buffer, currentdatamem->value);
+					error=strlen(currentdatamem->value);
+				  } else  error=-ERANGE; 
+			}else error=strlen(currentdatamem->value);
+		
+		}
+	}
+	return(error);
+}
+
 /*
  * UTF-8 to NLS charset  convert routine
  * 
@@ -846,6 +933,7 @@ befs_fill_super(struct super_block *sb, void *data, int silent)
 	if (befs_load_sb(sb, disk_sb) != BEFS_OK)
 		goto unacquire_bh;
 
+	sb->s_xattr = befs_xattr_handlers;
 	befs_dump_super_block(sb, disk_sb);
 
 	brelse(bh);
--
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