Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754704Ab0HHQCy (ORCPT ); Sun, 8 Aug 2010 12:02:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51085 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754579Ab0HHPym (ORCPT ); Sun, 8 Aug 2010 11:54:42 -0400 From: Valerie Aurora To: Alexander Viro Cc: Miklos Szeredi , Jan Blunck , Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Felix Fietkau , Valerie Aurora , David Woodhouse , linux-mtd@lists.infradead.org Subject: [PATCH 12/39] whiteout: jffs2 whiteout support Date: Sun, 8 Aug 2010 11:52:29 -0400 Message-Id: <1281282776-5447-13-git-send-email-vaurora@redhat.com> In-Reply-To: <1281282776-5447-1-git-send-email-vaurora@redhat.com> References: <1281282776-5447-1-git-send-email-vaurora@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5850 Lines: 187 From: Felix Fietkau Add support for whiteout dentries to jffs2. XXX - David Woodhouse suggests several changes and provides an untested patch. See: http://patchwork.ozlabs.org/patch/50466/ XXX - Backward compatibility? Creating a whiteout on a JFFS2 file system can only happen if it is deliberately mounted "-o union" so there is some way to prevent creation of whiteouts on a file system you want to later mount with an earlier (no support for whiteout) file system. However, ext2/3 has much more robust methods (explicit fs feature flag) to prevent such an occurance. Signed-off-by: Felix Fietkau Signed-off-by: Valerie Aurora Cc: David Woodhouse Cc: linux-mtd@lists.infradead.org --- fs/jffs2/dir.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++- fs/jffs2/fs.c | 4 +++ fs/jffs2/super.c | 2 +- include/linux/jffs2.h | 2 + 4 files changed, 77 insertions(+), 3 deletions(-) diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c index 166062a..4798586 100644 --- a/fs/jffs2/dir.c +++ b/fs/jffs2/dir.c @@ -34,6 +34,8 @@ static int jffs2_mknod (struct inode *,struct dentry *,int,dev_t); static int jffs2_rename (struct inode *, struct dentry *, struct inode *, struct dentry *); +static int jffs2_whiteout (struct inode *, struct dentry *, struct dentry *); + const struct file_operations jffs2_dir_operations = { .read = generic_read_dir, @@ -56,6 +58,7 @@ const struct inode_operations jffs2_dir_inode_operations = .mknod = jffs2_mknod, .rename = jffs2_rename, .check_acl = jffs2_check_acl, + .whiteout = jffs2_whiteout, .setattr = jffs2_setattr, .setxattr = jffs2_setxattr, .getxattr = jffs2_getxattr, @@ -98,8 +101,14 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target, fd = fd_list; } } - if (fd) - ino = fd->ino; + if (fd) { + spin_lock(&target->d_lock); + if (fd->type == DT_WHT) + target->d_flags |= DCACHE_WHITEOUT; + else + ino = fd->ino; + spin_unlock(&target->d_lock); + } mutex_unlock(&dir_f->sem); if (ino) { inode = jffs2_iget(dir_i->i_sb, ino); @@ -502,6 +511,11 @@ static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, int mode) 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; @@ -784,6 +798,60 @@ static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, int mode, de return ret; } +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_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) { diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c index 459d39d..cdb2667 100644 --- a/fs/jffs2/fs.c +++ b/fs/jffs2/fs.c @@ -301,6 +301,10 @@ struct inode *jffs2_iget(struct super_block *sb, unsigned long ino) 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: diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c index 511e2d6..f998679 100644 --- a/fs/jffs2/super.c +++ b/fs/jffs2/super.c @@ -170,7 +170,7 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent) 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; diff --git a/include/linux/jffs2.h b/include/linux/jffs2.h index 0874ab5..cc6347f 100644 --- 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 */ -- 1.6.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/