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add jffs2 whiteout support (necessary for using it with union mounts)

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git-svn-id: svn://svn.openwrt.org/openwrt/trunk@17745 3c298f89-4303-0410-b956-a3cf2f4a3e73
This commit is contained in:
nbd 2009-09-26 18:51:05 +00:00
parent aeae9956b5
commit cf5d9b9638
1 changed files with 186 additions and 0 deletions
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186
target/linux/generic-2.6/patches-2.6.31/233-jffs2_whiteout_support.patch Normal file
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@ -0,0 +1,186 @@
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -34,6 +34,9 @@
static int jffs2_rename (struct inode *, struct dentry *,
struct inode *, struct dentry *);
+static int jffs2_whiteout (struct inode *, struct dentry *, struct dentry *);
+static int jffs2_fallthru (struct inode *, struct dentry *);
+
const struct file_operations jffs2_dir_operations =
{
.read = generic_read_dir,
@@ -55,6 +58,8 @@
.rmdir = jffs2_rmdir,
.mknod = jffs2_mknod,
.rename = jffs2_rename,
+ .fallthru = jffs2_fallthru,
+ .whiteout = jffs2_whiteout,
.permission = jffs2_permission,
.setattr = jffs2_setattr,
.setxattr = jffs2_setxattr,
@@ -98,8 +103,21 @@
fd = fd_list;
}
}
- if (fd)
- ino = fd->ino;
+ if (fd) {
+ spin_lock(&target->d_lock);
+ switch(fd->type) {
+ case DT_WHT:
+ target->d_flags |= DCACHE_WHITEOUT;
+ break;
+ case DT_UNKNOWN:
+ target->d_flags |= DCACHE_FALLTHRU;
+ break;
+ default:
+ ino = fd->ino;
+ break;
+ }
+ spin_unlock(&target->d_lock);
+ }
mutex_unlock(&dir_f->sem);
if (ino) {
inode = jffs2_iget(dir_i->i_sb, ino);
@@ -155,7 +173,9 @@
fd->name, fd->ino, fd->type, curofs, offset));
continue;
}
- if (!fd->ino) {
+ if (fd->type == DT_UNKNOWN)
+ fd->ino = 100; /* XXX: arbitrary */
+ else if (!fd->ino && (fd->type != DT_WHT)) {
D2(printk(KERN_DEBUG "Skipping deletion dirent \"%s\"\n", fd->name));
offset++;
continue;
@@ -498,6 +518,11 @@
return PTR_ERR(inode);
}
+ if (dentry->d_flags & DCACHE_WHITEOUT) {
+ inode->i_flags |= S_OPAQUE;
+ ri->flags = cpu_to_je16(JFFS2_INO_FLAG_OPAQUE);
+ }
+
inode->i_op = &jffs2_dir_inode_operations;
inode->i_fop = &jffs2_dir_operations;
@@ -779,6 +804,82 @@
return 0;
}
+static int jffs2_fallthru (struct inode *dir, struct dentry *dentry)
+{
+ struct jffs2_sb_info *c = JFFS2_SB_INFO(dir->i_sb);
+ uint32_t now;
+ int ret;
+
+ now = get_seconds();
+ ret = jffs2_do_link(c, JFFS2_INODE_INFO(dir), 0, DT_UNKNOWN,
+ dentry->d_name.name, dentry->d_name.len, now);
+ if (ret)
+ return ret;
+
+ d_instantiate(dentry, NULL);
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_FALLTHRU;
+ spin_unlock(&dentry->d_lock);
+
+ return 0;
+}
+
+static int jffs2_whiteout (struct inode *dir, struct dentry *old_dentry,
+ struct dentry *new_dentry)
+{
+ struct jffs2_sb_info *c = JFFS2_SB_INFO(dir->i_sb);
+ struct jffs2_inode_info *victim_f = NULL;
+ uint32_t now;
+ int ret;
+
+ /* If it's a directory, then check whether it is really empty
+ */
+ if (new_dentry->d_inode) {
+ victim_f = JFFS2_INODE_INFO(old_dentry->d_inode);
+ if (S_ISDIR(old_dentry->d_inode->i_mode)) {
+ struct jffs2_full_dirent *fd;
+
+ mutex_lock(&victim_f->sem);
+ for (fd = victim_f->dents; fd; fd = fd->next) {
+ if (fd->ino) {
+ mutex_unlock(&victim_f->sem);
+ return -ENOTEMPTY;
+ }
+ }
+ mutex_unlock(&victim_f->sem);
+ }
+ }
+
+ now = get_seconds();
+ ret = jffs2_do_link(c, JFFS2_INODE_INFO(dir), 0, DT_WHT,
+ new_dentry->d_name.name, new_dentry->d_name.len, now);
+ if (ret)
+ return ret;
+
+ spin_lock(&new_dentry->d_lock);
+ new_dentry->d_flags &= ~DCACHE_FALLTHRU;
+ new_dentry->d_flags |= DCACHE_WHITEOUT;
+ spin_unlock(&new_dentry->d_lock);
+ d_add(new_dentry, NULL);
+
+ if (victim_f) {
+ /* There was a victim. Kill it off nicely */
+ drop_nlink(old_dentry->d_inode);
+ /* Don't oops if the victim was a dirent pointing to an
+ inode which didn't exist. */
+ if (victim_f->inocache) {
+ mutex_lock(&victim_f->sem);
+ if (S_ISDIR(old_dentry->d_inode->i_mode))
+ victim_f->inocache->pino_nlink = 0;
+ else
+ victim_f->inocache->pino_nlink--;
+ mutex_unlock(&victim_f->sem);
+ }
+ }
+
+ return 0;
+}
+
static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
struct inode *new_dir_i, struct dentry *new_dentry)
{
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -301,6 +301,10 @@
inode->i_op = &jffs2_dir_inode_operations;
inode->i_fop = &jffs2_dir_operations;
+
+ if (je16_to_cpu(latest_node.flags) & JFFS2_INO_FLAG_OPAQUE)
+ inode->i_flags |= S_OPAQUE;
+
break;
}
case S_IFREG:
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -172,7 +172,7 @@
sb->s_op = &jffs2_super_operations;
sb->s_export_op = &jffs2_export_ops;
- sb->s_flags = sb->s_flags | MS_NOATIME;
+ sb->s_flags = sb->s_flags | MS_NOATIME | MS_WHITEOUT;
sb->s_xattr = jffs2_xattr_handlers;
#ifdef CONFIG_JFFS2_FS_POSIX_ACL
sb->s_flags |= MS_POSIXACL;
--- a/include/linux/jffs2.h
+++ b/include/linux/jffs2.h
@@ -87,6 +87,8 @@
#define JFFS2_INO_FLAG_USERCOMPR 2 /* User has requested a specific
compression type */
+#define JFFS2_INO_FLAG_OPAQUE 4 /* Directory is opaque (for union mounts) */
+
/* These can go once we've made sure we've caught all uses without
byteswapping */