From: Valerie Aurora <vaurora@xxxxxxxxxx>
Add support for whiteouts to ext2.
---
fs/ext2/dir.c | 64 +++++++++++++++++++++++++++++++++++++++++------
fs/ext2/ext2.h | 2 +
fs/ext2/inode.c | 11 ++++++--
fs/ext2/namei.c | 63 ++++++++++++++++++++++++++++++++++++++++++++--
fs/ext2/super.c | 4 +++
include/linux/ext2_fs.h | 4 +++
6 files changed, 134 insertions(+), 14 deletions(-)
diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index 850a081..4ef5777 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -220,7 +220,7 @@ fail:
static inline int ext2_dirent_in_use(struct ext2_dir_entry_2 *de)
{
- return de->inode != 0;
+ return de->inode != 0 || de->file_type == EXT2_FT_WHT;
}
/*
@@ -269,6 +269,7 @@ static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
[EXT2_FT_FIFO] = DT_FIFO,
[EXT2_FT_SOCK] = DT_SOCK,
[EXT2_FT_SYMLINK] = DT_LNK,
+ [EXT2_FT_WHT] = DT_WHT,
};
#define S_SHIFT 12
@@ -467,6 +468,26 @@ static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
return __block_write_begin(page, pos, len, ext2_get_block);
}
+/* Special version for filetype based whiteout support */
+ino_t ext2_inode_by_dentry(struct inode *dir, struct dentry *dentry)
+{
+ ino_t res = 0;
+ struct ext2_dir_entry_2 *de;
+ struct page *page;
+
+ de = ext2_find_entry (dir, &dentry->d_name, &page);
+ if (de) {
+ res = le32_to_cpu(de->inode);
+ if (!res && de->file_type == EXT2_FT_WHT) {
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_WHITEOUT;
+ spin_unlock(&dentry->d_lock);
+ }
+ ext2_put_page(page);
+ }
+ return res;
+}
+
/* Releases the page */
void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
struct page *page, struct inode *inode, int update_times)
@@ -489,7 +510,9 @@ void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
mark_inode_dirty(dir);
}
-int ext2_add_entry (struct dentry *dentry, struct inode *inode)
+int ext2_add_entry (struct dentry *dentry, struct inode *inode,
+ ext2_dirent *de, struct page *page,
+ int new_file_type)
{
struct inode *dir = dentry->d_parent->d_inode;
const char *name = dentry->d_name.name;
@@ -497,8 +520,6 @@ int ext2_add_entry (struct dentry *dentry, struct inode *inode)
unsigned chunk_size = ext2_chunk_size(dir);
unsigned reclen = EXT2_DIR_REC_LEN(namelen);
unsigned short rec_len, name_len;
- struct page *page = NULL;
- ext2_dirent * de;
unsigned long npages = dir_pages(dir);
unsigned long n;
char *kaddr;
@@ -556,12 +577,27 @@ int ext2_add_entry (struct dentry *dentry, struct inode *inode)
return -EINVAL;
got_it:
+ /*
+ * Pre-existing entries with the same name are allowable
+ * depending on the type of the entry being created. Regular
+ * entries replace whiteouts. Whiteouts replace regular
+ * entries.
+ */
+ err = -EEXIST;
+ if (ext2_match(namelen, name, de)) {
+ if (new_file_type == EXT2_FT_WHT) {
+ if (de->file_type == EXT2_FT_WHT)
+ goto out_unlock;
+ } else if (de->file_type != EXT2_FT_WHT) {
+ goto out_unlock;
+ }
+ }
pos = page_offset(page) +
(char*)de - (char*)page_address(page);
err = ext2_prepare_chunk(page, pos, rec_len);
if (err)
goto out_unlock;
- if (ext2_dirent_in_use(de)) {
+ if (ext2_dirent_in_use(de) && !ext2_match (namelen, name, de)) {
ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
de->rec_len = ext2_rec_len_to_disk(name_len);
@@ -569,8 +605,13 @@ got_it:
}
de->name_len = namelen;
memcpy(de->name, name, namelen);
- de->inode = cpu_to_le32(inode->i_ino);
- ext2_set_de_type (de, inode);
+ if (inode) {
+ de->inode = cpu_to_le32(inode->i_ino);
+ ext2_set_de_type (de, inode);
+ } else {
+ de->inode = 0;
+ de->file_type = new_file_type;
+ }
err = ext2_commit_chunk(page, pos, rec_len);
dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
@@ -587,7 +628,14 @@ out_unlock:
int ext2_add_link (struct dentry *dentry, struct inode *inode)
{
- return ext2_add_entry(dentry, inode);
+ ext2_dirent *de = NULL;
+ struct page *page = NULL;
+ return ext2_add_entry(dentry, inode, de, page, 0);
+}
+
+int ext2_whiteout_entry (struct dentry *dentry, ext2_dirent *de, struct page *page)
+{
+ return ext2_add_entry(dentry, NULL, de, page, EXT2_FT_WHT);
}
/*
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 645be9e..78719f4 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -102,9 +102,11 @@ extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_wind
/* dir.c */
extern int ext2_add_link (struct dentry *, struct inode *);
extern ino_t ext2_inode_by_name(struct inode *, struct qstr *);
+extern ino_t ext2_inode_by_dentry(struct inode *, struct dentry *);
extern int ext2_make_empty(struct inode *, struct inode *);
extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,struct qstr *, struct page **);
extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
+extern int ext2_whiteout_entry (struct dentry *, struct ext2_dir_entry_2 *, struct page *);
extern int ext2_empty_dir (struct inode *);
extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 788e09a..42c8b8d 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1256,7 +1256,8 @@ void ext2_set_inode_flags(struct inode *inode)
{
unsigned int flags = EXT2_I(inode)->i_flags;
- inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
+ inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|
+ S_OPAQUE);
if (flags & EXT2_SYNC_FL)
inode->i_flags |= S_SYNC;
if (flags & EXT2_APPEND_FL)
@@ -1267,6 +1268,8 @@ void ext2_set_inode_flags(struct inode *inode)
inode->i_flags |= S_NOATIME;
if (flags & EXT2_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
+ if (flags & EXT2_OPAQUE_FL)
+ inode->i_flags |= S_OPAQUE;
}
/* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
@@ -1274,8 +1277,8 @@ void ext2_get_inode_flags(struct ext2_inode_info *ei)
{
unsigned int flags = ei->vfs_inode.i_flags;
- ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
- EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
+ ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|EXT2_IMMUTABLE_FL|
+ EXT2_NOATIME_FL|EXT2_DIRSYNC_FL|EXT2_OPAQUE_FL);
if (flags & S_SYNC)
ei->i_flags |= EXT2_SYNC_FL;
if (flags & S_APPEND)
@@ -1286,6 +1289,8 @@ void ext2_get_inode_flags(struct ext2_inode_info *ei)
ei->i_flags |= EXT2_NOATIME_FL;
if (flags & S_DIRSYNC)
ei->i_flags |= EXT2_DIRSYNC_FL;
+ if (flags & S_OPAQUE)
+ ei->i_flags |= EXT2_OPAQUE_FL;
}
struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index ed5c5d4..a17c9c8 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -55,15 +55,16 @@ static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
* Methods themselves.
*/
-static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
+static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry,
+ struct nameidata *nd)
{
struct inode * inode;
ino_t ino;
-
+
if (dentry->d_name.len > EXT2_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);
- ino = ext2_inode_by_name(dir, &dentry->d_name);
+ ino = ext2_inode_by_dentry(dir, dentry);
inode = NULL;
if (ino) {
inode = ext2_iget(dir->i_sb, ino);
@@ -307,6 +308,61 @@ static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
return err;
}
+/*
+ * Create a whiteout for the dentry
+ */
+static int ext2_whiteout(struct inode *dir, struct dentry *dentry,
+ struct dentry *new_dentry)
+{
+ struct inode * inode = dentry->d_inode;
+ struct ext2_dir_entry_2 * de = NULL;
+ struct page * page;
+ int err = -ENOTEMPTY;
+
+ if (!EXT2_HAS_INCOMPAT_FEATURE(dir->i_sb,
+ EXT2_FEATURE_INCOMPAT_FILETYPE)) {
+ ext2_error (dir->i_sb, "ext2_whiteout",
+ "can't set whiteout filetype");
+ err = -EPERM;
+ goto out;
+ }
+
+ dquot_initialize(dir);
+
+ if (inode) {
+ if (S_ISDIR(inode->i_mode) && !ext2_empty_dir(inode))
+ goto out;
+
+ err = -ENOENT;
+ de = ext2_find_entry(dir, &dentry->d_name, &page);
+ if (!de)
+ goto out;
+ lock_page(page);
+ }
+
+ err = ext2_whiteout_entry(dentry, de, page);
+ if (err)
+ goto out;
+
+ spin_lock(&new_dentry->d_lock);
+ new_dentry->d_flags |= DCACHE_WHITEOUT;
+ spin_unlock(&new_dentry->d_lock);
+ d_add(new_dentry, NULL);
+
+ if (inode) {
+ inode->i_ctime = dir->i_ctime;
+ inode_dec_link_count(inode);
+ if (S_ISDIR(inode->i_mode)) {
+ inode->i_size = 0;
+ inode_dec_link_count(inode);
+ inode_dec_link_count(dir);
+ }
+ }
+ err = 0;
+out:
+ return err;
+}
+
static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry )
{
@@ -404,6 +460,7 @@ const struct inode_operations ext2_dir_inode_operations = {
.mkdir = ext2_mkdir,
.rmdir = ext2_rmdir,
.mknod = ext2_mknod,
+ .whiteout = ext2_whiteout,
.rename = ext2_rename,
#ifdef CONFIG_EXT2_FS_XATTR
.setxattr = generic_setxattr,
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 1dd62ed..6167ff3 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -1098,6 +1098,10 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
ext2_msg(sb, KERN_WARNING,
"warning: mounting ext3 filesystem as ext2");
+
+ if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_WHITEOUT))
+ sb->s_flags |= MS_WHITEOUT;
+
if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
sb->s_flags |= MS_RDONLY;
ext2_write_super(sb);
diff --git a/include/linux/ext2_fs.h b/include/linux/ext2_fs.h
index 2dfa707..b0fb356 100644
--- a/include/linux/ext2_fs.h
+++ b/include/linux/ext2_fs.h
@@ -189,6 +189,7 @@ struct ext2_group_desc
#define EXT2_NOTAIL_FL FS_NOTAIL_FL /* file tail should not be merged */
#define EXT2_DIRSYNC_FL FS_DIRSYNC_FL /* dirsync behaviour (directories only) */
#define EXT2_TOPDIR_FL FS_TOPDIR_FL /* Top of directory hierarchies*/
+#define EXT2_OPAQUE_FL FS_OPAQUE_FL /* Dir is opaque */
#define EXT2_RESERVED_FL FS_RESERVED_FL /* reserved for ext2 lib */
#define EXT2_FL_USER_VISIBLE FS_FL_USER_VISIBLE /* User visible flags */
@@ -503,10 +504,12 @@ struct ext2_super_block {
#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008
#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
+#define EXT2_FEATURE_INCOMPAT_WHITEOUT 0x0020
#define EXT2_FEATURE_INCOMPAT_ANY 0xffffffff
#define EXT2_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
#define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
+ EXT2_FEATURE_INCOMPAT_WHITEOUT| \
EXT2_FEATURE_INCOMPAT_META_BG)
#define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
@@ -573,6 +576,7 @@ enum {
EXT2_FT_FIFO = 5,
EXT2_FT_SOCK = 6,
EXT2_FT_SYMLINK = 7,
+ EXT2_FT_WHT = 8,
EXT2_FT_MAX
};
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