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ANDROID: sdcardfs: Replace get/put with d_lock

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dput cannot be called with a spin_lock. Instead,
we protect our accesses by holding the d_lock.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 35643557
Change-Id: I22cf30856d75b5616cbb0c223724f5ab866b5114
This commit is contained in:
Daniel Rosenberg 2017-03-02 15:11:27 -08:00 committed by Amit Pundir
parent da6242a966
commit 7f82ad04c9
1 changed files with 20 additions and 13 deletions
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33
fs/sdcardfs/derived_perm.c
View file

@ -264,41 +264,48 @@ static int needs_fixup(perm_t perm) {
return 0;
}
void fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit)
static void __fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit, int depth)
{
struct dentry *child;
struct sdcardfs_inode_info *info;
if (!dget(dentry))
return;
/*
* All paths will terminate their recursion on hitting PERM_ANDROID_OBB,
* PERM_ANDROID_MEDIA, or PERM_ANDROID_DATA. This happens at a depth of
* at most 3.
*/
WARN(depth > 3, "%s: Max expected depth exceeded!\n", __func__);
spin_lock_nested(&dentry->d_lock, depth);
if (!d_inode(dentry)) {
dput(dentry);
spin_unlock(&dentry->d_lock);
return;
}
info = SDCARDFS_I(d_inode(dentry));
if (needs_fixup(info->perm)) {
spin_lock(&dentry->d_lock);
list_for_each_entry(child, &dentry->d_subdirs, d_child) {
dget(child);
spin_lock_nested(&child->d_lock, depth + 1);
if (!(limit->flags & BY_NAME) || !strncasecmp(child->d_name.name, limit->name, limit->length)) {
if (d_inode(child)) {
get_derived_permission(dentry, child);
fixup_tmp_permissions(d_inode(child));
dput(child);
spin_unlock(&child->d_lock);
break;
}
}
dput(child);
spin_unlock(&child->d_lock);
}
spin_unlock(&dentry->d_lock);
} else if (descendant_may_need_fixup(info, limit)) {
spin_lock(&dentry->d_lock);
list_for_each_entry(child, &dentry->d_subdirs, d_child) {
fixup_perms_recursive(child, limit);
__fixup_perms_recursive(child, limit, depth + 1);
}
spin_unlock(&dentry->d_lock);
}
dput(dentry);
spin_unlock(&dentry->d_lock);
}
void fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit)
{
__fixup_perms_recursive(dentry, limit, 0);
}
void drop_recursive(struct dentry *parent)