[JFFS2] Fix race in garbage collector

Fix the race problem described here:
http://lists.infradead.org/pipermail/linux-mtd/2005-April/012361.html

Signed-off-by: Artem B. Bityuckiy <dedekind@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/fs/jffs2/gc.c b/fs/jffs2/gc.c
index 694bc90ad77997a72b0c0b1bdde39d734219fa42..7086cd6345038cbc9015dacb4b23dcaf7f4f081f 100644 (file)
--- a/fs/jffs2/gc.c
+++ b/fs/jffs2/gc.c
@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: gc.c,v 1.147 2005/03/20 21:43:22 dedekind Exp $
+ * $Id: gc.c,v 1.148 2005/04/09 10:47:00 dedekind Exp $
  *
  */
 
@@ -669,9 +669,10 @@ static int jffs2_garbage_collect_metadata(struct jffs2_sb_info *c, struct jffs2_
 {
        struct jffs2_full_dnode *new_fn;
        struct jffs2_raw_inode ri;
+       struct jffs2_node_frag *last_frag;
        jint16_t dev;
        char *mdata = NULL, mdatalen = 0;
-       uint32_t alloclen, phys_ofs;
+       uint32_t alloclen, phys_ofs, ilen;
        int ret;
 
        if (S_ISBLK(JFFS2_F_I_MODE(f)) ||
@@ -707,6 +708,14 @@ static int jffs2_garbage_collect_metadata(struct jffs2_sb_info *c, struct jffs2_
                goto out;
        }
        
+       last_frag = frag_last(&f->fragtree);
+       if (last_frag)
+               /* Fetch the inode length from the fragtree rather then
+                * from i_size since i_size may have not been updated yet */
+               ilen = last_frag->ofs + last_frag->size;
+       else
+               ilen = JFFS2_F_I_SIZE(f);
+       
        memset(&ri, 0, sizeof(ri));
        ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
        ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
@@ -718,7 +727,7 @@ static int jffs2_garbage_collect_metadata(struct jffs2_sb_info *c, struct jffs2_
        ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
        ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
        ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
-       ri.isize = cpu_to_je32(JFFS2_F_I_SIZE(f));
+       ri.isize = cpu_to_je32(ilen);
        ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
        ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
        ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
@@ -898,7 +907,7 @@ static int jffs2_garbage_collect_hole(struct jffs2_sb_info *c, struct jffs2_eras
        struct jffs2_raw_inode ri;
        struct jffs2_node_frag *frag;
        struct jffs2_full_dnode *new_fn;
-       uint32_t alloclen, phys_ofs;
+       uint32_t alloclen, phys_ofs, ilen;
        int ret;
 
        D1(printk(KERN_DEBUG "Writing replacement hole node for ino #%u from offset 0x%x to 0x%x\n",
@@ -958,10 +967,19 @@ static int jffs2_garbage_collect_hole(struct jffs2_sb_info *c, struct jffs2_eras
                ri.csize = cpu_to_je32(0);
                ri.compr = JFFS2_COMPR_ZERO;
        }
+       
+       frag = frag_last(&f->fragtree);
+       if (frag)
+               /* Fetch the inode length from the fragtree rather then
+                * from i_size since i_size may have not been updated yet */
+               ilen = frag->ofs + frag->size;
+       else
+               ilen = JFFS2_F_I_SIZE(f);
+
        ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
        ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
        ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
-       ri.isize = cpu_to_je32(JFFS2_F_I_SIZE(f));
+       ri.isize = cpu_to_je32(ilen);
        ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
        ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
        ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
@@ -1168,7 +1186,7 @@ static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_era
                D1(printk(KERN_DEBUG "Expanded dnode to write from (0x%x-0x%x) to (0x%x-0x%x)\n", 
                          orig_start, orig_end, start, end));
 
-               BUG_ON(end > JFFS2_F_I_SIZE(f));
+               D1(BUG_ON(end > frag_last(&f->fragtree)->ofs + frag_last(&f->fragtree)->size));
                BUG_ON(end < orig_end);
                BUG_ON(start > orig_start);
        }

diff --git a/fs/jffs2/nodelist.h b/fs/jffs2/nodelist.h
index 57f675c2c97f492c7aeee3dee8191231d8face11..a65539f28b067fdae3fa92627403530525ea7c75 100644 (file)
--- a/fs/jffs2/nodelist.h
+++ b/fs/jffs2/nodelist.h
@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: nodelist.h,v 1.128 2005/02/27 23:01:32 dwmw2 Exp $
+ * $Id: nodelist.h,v 1.130 2005/04/09 10:46:59 dedekind Exp $
  *
  */
 
@@ -363,6 +363,18 @@ static inline struct jffs2_node_frag *frag_first(struct rb_root *root)
                node = node->rb_left;
        return rb_entry(node, struct jffs2_node_frag, rb);
 }
+
+static inline struct jffs2_node_frag *frag_last(struct rb_root *root)
+{
+       struct rb_node *node = root->rb_node;
+
+       if (!node)
+               return NULL;
+       while(node->rb_right)
+               node = node->rb_right;
+       return rb_entry(node, struct jffs2_node_frag, rb);
+}
+
 #define rb_parent(rb) ((rb)->rb_parent)
 #define frag_next(frag) rb_entry(rb_next(&(frag)->rb), struct jffs2_node_frag, rb)
 #define frag_prev(frag) rb_entry(rb_prev(&(frag)->rb), struct jffs2_node_frag, rb)