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Diffstat (limited to 'fs/sdcardfs/lookup.c')
-rw-r--r--fs/sdcardfs/lookup.c167
1 files changed, 113 insertions, 54 deletions
diff --git a/fs/sdcardfs/lookup.c b/fs/sdcardfs/lookup.c
index 9135866b7766..f10f7752f514 100644
--- a/fs/sdcardfs/lookup.c
+++ b/fs/sdcardfs/lookup.c
@@ -36,8 +36,7 @@ int sdcardfs_init_dentry_cache(void)
void sdcardfs_destroy_dentry_cache(void)
{
- if (sdcardfs_dentry_cachep)
- kmem_cache_destroy(sdcardfs_dentry_cachep);
+ kmem_cache_destroy(sdcardfs_dentry_cachep);
}
void free_dentry_private_data(struct dentry *dentry)
@@ -73,6 +72,7 @@ static int sdcardfs_inode_test(struct inode *inode, void *candidate_data/*void *
{
struct inode *current_lower_inode = sdcardfs_lower_inode(inode);
userid_t current_userid = SDCARDFS_I(inode)->userid;
+
if (current_lower_inode == ((struct inode_data *)candidate_data)->lower_inode &&
current_userid == ((struct inode_data *)candidate_data)->id)
return 1; /* found a match */
@@ -102,7 +102,7 @@ struct inode *sdcardfs_iget(struct super_block *sb, struct inode *lower_inode, u
* instead.
*/
lower_inode->i_ino, /* hashval */
- sdcardfs_inode_test, /* inode comparison function */
+ sdcardfs_inode_test, /* inode comparison function */
sdcardfs_inode_set, /* inode init function */
&data); /* data passed to test+set fxns */
if (!inode) {
@@ -164,27 +164,25 @@ struct inode *sdcardfs_iget(struct super_block *sb, struct inode *lower_inode, u
}
/*
- * Connect a sdcardfs inode dentry/inode with several lower ones. This is
- * the classic stackable file system "vnode interposition" action.
- *
- * @dentry: sdcardfs's dentry which interposes on lower one
- * @sb: sdcardfs's super_block
- * @lower_path: the lower path (caller does path_get/put)
+ * Helper interpose routine, called directly by ->lookup to handle
+ * spliced dentries.
*/
-int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
- struct path *lower_path, userid_t id)
+static struct dentry *__sdcardfs_interpose(struct dentry *dentry,
+ struct super_block *sb,
+ struct path *lower_path,
+ userid_t id)
{
- int err = 0;
struct inode *inode;
struct inode *lower_inode;
struct super_block *lower_sb;
+ struct dentry *ret_dentry;
lower_inode = d_inode(lower_path->dentry);
lower_sb = sdcardfs_lower_super(sb);
/* check that the lower file system didn't cross a mount point */
if (lower_inode->i_sb != lower_sb) {
- err = -EXDEV;
+ ret_dentry = ERR_PTR(-EXDEV);
goto out;
}
@@ -196,14 +194,54 @@ int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
/* inherit lower inode number for sdcardfs's inode */
inode = sdcardfs_iget(sb, lower_inode, id);
if (IS_ERR(inode)) {
- err = PTR_ERR(inode);
+ ret_dentry = ERR_CAST(inode);
goto out;
}
- d_add(dentry, inode);
+ ret_dentry = d_splice_alias(inode, dentry);
+ dentry = ret_dentry ?: dentry;
update_derived_permission_lock(dentry);
out:
- return err;
+ return ret_dentry;
+}
+
+/*
+ * Connect an sdcardfs inode dentry/inode with several lower ones. This is
+ * the classic stackable file system "vnode interposition" action.
+ *
+ * @dentry: sdcardfs's dentry which interposes on lower one
+ * @sb: sdcardfs's super_block
+ * @lower_path: the lower path (caller does path_get/put)
+ */
+int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
+ struct path *lower_path, userid_t id)
+{
+ struct dentry *ret_dentry;
+
+ ret_dentry = __sdcardfs_interpose(dentry, sb, lower_path, id);
+ return PTR_ERR(ret_dentry);
+}
+
+struct sdcardfs_name_data {
+ struct dir_context ctx;
+ const struct qstr *to_find;
+ char *name;
+ bool found;
+};
+
+static int sdcardfs_name_match(struct dir_context *ctx, const char *name,
+ int namelen, loff_t offset, u64 ino, unsigned int d_type)
+{
+ struct sdcardfs_name_data *buf = container_of(ctx, struct sdcardfs_name_data, ctx);
+ struct qstr candidate = QSTR_INIT(name, namelen);
+
+ if (qstr_case_eq(buf->to_find, &candidate)) {
+ memcpy(buf->name, name, namelen);
+ buf->name[namelen] = 0;
+ buf->found = true;
+ return 1;
+ }
+ return 0;
}
/*
@@ -221,6 +259,8 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
struct dentry *lower_dentry;
const struct qstr *name;
struct path lower_path;
+ struct qstr dname;
+ struct dentry *ret_dentry = NULL;
struct sdcardfs_sb_info *sbi;
sbi = SDCARDFS_SB(dentry->d_sb);
@@ -241,60 +281,79 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
&lower_path);
/* check for other cases */
if (err == -ENOENT) {
- struct dentry *child;
- struct dentry *match = NULL;
- mutex_lock(&d_inode(lower_dir_dentry)->i_mutex);
- spin_lock(&lower_dir_dentry->d_lock);
- list_for_each_entry(child, &lower_dir_dentry->d_subdirs, d_child) {
- if (child && d_inode(child)) {
- if (qstr_case_eq(&child->d_name, name)) {
- match = dget(child);
- break;
- }
- }
+ struct file *file;
+ const struct cred *cred = current_cred();
+
+ struct sdcardfs_name_data buffer = {
+ .ctx.actor = sdcardfs_name_match,
+ .to_find = name,
+ .name = __getname(),
+ .found = false,
+ };
+
+ if (!buffer.name) {
+ err = -ENOMEM;
+ goto out;
+ }
+ file = dentry_open(lower_parent_path, O_RDONLY, cred);
+ if (IS_ERR(file)) {
+ err = PTR_ERR(file);
+ goto put_name;
}
- spin_unlock(&lower_dir_dentry->d_lock);
- mutex_unlock(&d_inode(lower_dir_dentry)->i_mutex);
- if (match) {
+ err = iterate_dir(file, &buffer.ctx);
+ fput(file);
+ if (err)
+ goto put_name;
+
+ if (buffer.found)
err = vfs_path_lookup(lower_dir_dentry,
lower_dir_mnt,
- match->d_name.name, 0,
+ buffer.name, 0,
&lower_path);
- dput(match);
- }
+ else
+ err = -ENOENT;
+put_name:
+ __putname(buffer.name);
}
/* no error: handle positive dentries */
if (!err) {
/* check if the dentry is an obb dentry
* if true, the lower_inode must be replaced with
- * the inode of the graft path */
+ * the inode of the graft path
+ */
- if(need_graft_path(dentry)) {
+ if (need_graft_path(dentry)) {
/* setup_obb_dentry()
- * The lower_path will be stored to the dentry's orig_path
+ * The lower_path will be stored to the dentry's orig_path
* and the base obbpath will be copyed to the lower_path variable.
* if an error returned, there's no change in the lower_path
- * returns: -ERRNO if error (0: no error) */
+ * returns: -ERRNO if error (0: no error)
+ */
err = setup_obb_dentry(dentry, &lower_path);
- if(err) {
+ if (err) {
/* if the sbi->obbpath is not available, we can optionally
* setup the lower_path with its orig_path.
* but, the current implementation just returns an error
* because the sdcard daemon also regards this case as
- * a lookup fail. */
- printk(KERN_INFO "sdcardfs: base obbpath is not available\n");
+ * a lookup fail.
+ */
+ pr_info("sdcardfs: base obbpath is not available\n");
sdcardfs_put_reset_orig_path(dentry);
goto out;
}
}
sdcardfs_set_lower_path(dentry, &lower_path);
- err = sdcardfs_interpose(dentry, dentry->d_sb, &lower_path, id);
- if (err) /* path_put underlying path on error */
+ ret_dentry =
+ __sdcardfs_interpose(dentry, dentry->d_sb, &lower_path, id);
+ if (IS_ERR(ret_dentry)) {
+ err = PTR_ERR(ret_dentry);
+ /* path_put underlying path on error */
sdcardfs_put_reset_lower_path(dentry);
+ }
goto out;
}
@@ -306,11 +365,14 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
goto out;
/* instatiate a new negative dentry */
- lower_dentry = d_lookup(lower_dir_dentry, name);
+ dname.name = name->name;
+ dname.len = name->len;
+ dname.hash = full_name_hash(dname.name, dname.len);
+ lower_dentry = d_lookup(lower_dir_dentry, &dname);
if (lower_dentry)
goto setup_lower;
- lower_dentry = d_alloc(lower_dir_dentry, name);
+ lower_dentry = d_alloc(lower_dir_dentry, &dname);
if (!lower_dentry) {
err = -ENOMEM;
goto out;
@@ -331,14 +393,16 @@ setup_lower:
err = 0;
out:
- return ERR_PTR(err);
+ if (err)
+ return ERR_PTR(err);
+ return ret_dentry;
}
/*
* On success:
- * fills dentry object appropriate values and returns NULL.
+ * fills dentry object appropriate values and returns NULL.
* On fail (== error)
- * returns error ptr
+ * returns error ptr
*
* @dir : Parent inode. It is locked (dir->i_mutex)
* @dentry : Target dentry to lookup. we should set each of fields.
@@ -355,13 +419,10 @@ struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
parent = dget_parent(dentry);
- if(!check_caller_access_to_name(d_inode(parent), &dentry->d_name)) {
+ if (!check_caller_access_to_name(d_inode(parent), &dentry->d_name)) {
ret = ERR_PTR(-EACCES);
- printk(KERN_INFO "%s: need to check the caller's gid in packages.list\n"
- " dentry: %s, task:%s\n",
- __func__, dentry->d_name.name, current->comm);
goto out_err;
- }
+ }
/* save current_cred and override it */
OVERRIDE_CRED_PTR(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
@@ -377,9 +438,7 @@ struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
ret = __sdcardfs_lookup(dentry, flags, &lower_parent_path, SDCARDFS_I(dir)->userid);
if (IS_ERR(ret))
- {
goto out;
- }
if (ret)
dentry = ret;
if (d_inode(dentry)) {