[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)

This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 15 insertions, 1 deletions

diff --git a/fs/jffs2/gc.c b/fs/jffs2/gc.c
index 967fb2cf8e21..4ea1b7f0ae78 100644
--- a/fs/jffs2/gc.c
+++ b/fs/jffs2/gc.c
@@ -125,6 +125,7 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
         struct jffs2_eraseblock *jeb;
         struct jffs2_raw_node_ref *raw;
         int ret = 0, inum, nlink;
+        int xattr = 0;
 
         if (down_interruptible(&c->alloc_sem))
                 return -EINTR;
@@ -138,7 +139,7 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
                    the node CRCs etc. Do it now. */
 
                 /* checked_ino is protected by the alloc_sem */
-                if (c->checked_ino > c->highest_ino) {
+                if (c->checked_ino > c->highest_ino && xattr) {
                         printk(KERN_CRIT "Checked all inodes but still 0x%x bytes of unchecked space?\n",
                                c->unchecked_size);
                         jffs2_dbg_dump_block_lists_nolock(c);
@@ -148,6 +149,9 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
 
                 spin_unlock(&c->erase_completion_lock);
 
+                if (!xattr)
+                        xattr = jffs2_verify_xattr(c);
+
                 spin_lock(&c->inocache_lock);
 
                 ic = jffs2_get_ino_cache(c, c->checked_ino++);
@@ -262,6 +266,16 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
 
         ic = jffs2_raw_ref_to_ic(raw);
 
+        /* When 'ic' refers xattr_datum/xattr_ref, this node is GCed as xattr.
+           We can decide whether this node is inode or xattr by ic->class.
+           ret = 0 : ic is xattr_datum/xattr_ref, and GC was SUCCESSED.
+           ret < 0 : ic is xattr_datum/xattr_ref, but GC was FAILED.
+           ret > 0 : ic is NOT xattr_datum/xattr_ref.
+        */
+        ret = jffs2_garbage_collect_xattr(c, ic);
+        if (ret <= 0)
+                goto release_sem;
+
         /* We need to hold the inocache. Either the erase_completion_lock or
            the inocache_lock are sufficient; we trade down since the inocache_lock
            causes less contention. */