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Subject[PATCH 69/73] ext2: Add fallthru support [ver #2]
Date
From: Valerie Aurora <vaurora@redhat.com>

Add support for fallthru directory entries to ext2.

Signed-off-by: Valerie Aurora <vaurora@redhat.com>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
---

fs/ext2/dir.c | 49 +++++++++++++++++++++++++++++++++++++++++------
fs/ext2/ext2.h | 1 +
fs/ext2/namei.c | 22 +++++++++++++++++++++
fs/ext2/super.c | 2 ++
include/linux/ext2_fs.h | 4 ++++
5 files changed, 72 insertions(+), 6 deletions(-)

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index df4d6b1..5fd6bbe 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -220,7 +220,9 @@ fail:

static inline int ext2_dirent_in_use(struct ext2_dir_entry_2 *de)
{
- return de->inode != 0 || de->file_type == EXT2_FT_WHT;
+ return de->inode != 0 ||
+ de->file_type == EXT2_FT_WHT ||
+ de->file_type == EXT2_FT_FALLTHRU;
}

/*
@@ -270,6 +272,7 @@ static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
[EXT2_FT_SOCK] = DT_SOCK,
[EXT2_FT_SYMLINK] = DT_LNK,
[EXT2_FT_WHT] = DT_WHT,
+ [EXT2_FT_FALLTHRU] = DT_UNKNOWN,
};

#define S_SHIFT 12
@@ -355,8 +358,20 @@ ext2_readdir (struct file * filp, void * dirent, filldir_t filldir)

offset = (char *)de - kaddr;
over = filldir(dirent, de->name, de->name_len,
- (n<<PAGE_CACHE_SHIFT) | offset,
- le32_to_cpu(de->inode), d_type);
+ (n << PAGE_CACHE_SHIFT) | offset,
+ le32_to_cpu(de->inode), d_type);
+ if (over) {
+ ext2_put_page(page);
+ return 0;
+ }
+ } else if (de->file_type == EXT2_FT_FALLTHRU) {
+ int over;
+
+ offset = (char *)de - kaddr;
+ /* XXX placeholder until generic_readdir_fallthru() arrives */
+ over = filldir(dirent, de->name, de->name_len,
+ (n<<PAGE_CACHE_SHIFT) | offset,
+ 1, DT_UNKNOWN); /* XXX */
if (over) {
ext2_put_page(page);
return 0;
@@ -487,6 +502,10 @@ ino_t ext2_inode_by_dentry(struct inode *dir, struct dentry *dentry)
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_WHITEOUT;
spin_unlock(&dentry->d_lock);
+ } else if (!res && de->file_type == EXT2_FT_FALLTHRU) {
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_FALLTHRU;
+ spin_unlock(&dentry->d_lock);
}
ext2_put_page(page);
}
@@ -580,7 +599,9 @@ int ext2_add_entry(struct dentry *dentry, ino_t ino, umode_t mode,
rec_len = ext2_rec_len_from_disk(de->rec_len);
if (ext2_match(namelen, name, de)) {
err = -EEXIST;
- /* XXX handle whiteouts and fallthroughs here */
+ /* XXX handle whiteouts here too */
+ if (de->file_type != EXT2_FT_FALLTHRU)
+ goto out_unlock;
printk("%s: found existing de\n", dentry->d_name.name);
goto got_it;
}
@@ -619,9 +640,17 @@ got_it:
err = -EEXIST;
if (ext2_match(namelen, name, de)) {
switch (de->file_type) {
+ case EXT2_FT_FALLTHRU:
+ if (new_file_type == EXT2_FT_FALLTHRU) {
+ WARN(1, "Ext2: Can't turn fallthru into fallthru: %s\n",
+ dentry->d_name.name);
+ goto out_unlock;
+ }
+ break;
case EXT2_FT_WHT:
- if (new_file_type == EXT2_FT_WHT) {
- WARN(1, "Ext2: Can't turn whiteout into whiteout: %s\n",
+ if (new_file_type == EXT2_FT_WHT ||
+ new_file_type == EXT2_FT_FALLTHRU) {
+ WARN(1, "Ext2: Can't turn whiteout into fallthru/whiteout: %s\n",
dentry->d_name.name);
goto out_unlock;
}
@@ -675,6 +704,14 @@ int ext2_whiteout_entry(struct dentry *dentry)
}

/*
+ * Create a fallthru entry.
+ */
+int ext2_fallthru_entry(struct dentry *dentry)
+{
+ return ext2_add_entry(dentry, 0, 0, EXT2_FT_FALLTHRU);
+}
+
+/*
* ext2_delete_entry deletes a directory entry by merging it with the
* previous entry. Page is up-to-date. Releases the page.
*/
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index b285d9a..dd82bc6 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -107,6 +107,7 @@ 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 *);
+extern int ext2_fallthru_entry(struct dentry *);
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/namei.c b/fs/ext2/namei.c
index 8227267..957c4b9 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -331,6 +331,7 @@ static int ext2_whiteout(struct inode *dir, struct dentry *dentry,
goto out;

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);
@@ -349,6 +350,26 @@ out:
return err;
}

+/*
+ * Create a fallthru entry.
+ */
+static int ext2_fallthru(struct inode *dir, struct dentry *dentry)
+{
+ int err;
+
+ dquot_initialize(dir);
+
+ err = ext2_fallthru_entry(dentry);
+ if (err)
+ return err;
+
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_FALLTHRU;
+ spin_unlock(&dentry->d_lock);
+ d_instantiate(dentry, NULL);
+ return 0;
+}
+
static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry )
{
@@ -447,6 +468,7 @@ const struct inode_operations ext2_dir_inode_operations = {
.rmdir = ext2_rmdir,
.mknod = ext2_mknod,
.whiteout = ext2_whiteout,
+ .fallthru = ext2_fallthru,
.rename = ext2_rename,
#ifdef CONFIG_EXT2_FS_XATTR
.setxattr = generic_setxattr,
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 8869794..bafd421 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -1100,6 +1100,8 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)

if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_WHITEOUT))
sb->s_flags |= MS_WHITEOUT;
+ if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FALLTHRU))
+ sb->s_flags |= MS_FALLTHRU;

if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
sb->s_flags |= MS_RDONLY;
diff --git a/include/linux/ext2_fs.h b/include/linux/ext2_fs.h
index 2202faa..cd6d533 100644
--- a/include/linux/ext2_fs.h
+++ b/include/linux/ext2_fs.h
@@ -506,11 +506,14 @@ struct ext2_super_block {
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008
#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
#define EXT2_FEATURE_INCOMPAT_WHITEOUT 0x0020
+/* ext3/4 incompat flags take up the intervening constants */
+#define EXT2_FEATURE_INCOMPAT_FALLTHRU 0x2000
#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_FALLTHRU| \
EXT2_FEATURE_INCOMPAT_META_BG)
#define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
@@ -578,6 +581,7 @@ enum {
EXT2_FT_SOCK = 6,
EXT2_FT_SYMLINK = 7,
EXT2_FT_WHT = 8,
+ EXT2_FT_FALLTHRU = 9,
EXT2_FT_MAX
};



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