/* unionfs_open helper function: open a directory */
static int __open_dir(struct inode *inode, struct file *file)
{
struct dentry *lower_dentry;
struct file *lower_file;
int bindex, bstart, bend;
struct vfsmount *mnt;
bstart = fbstart(file) = dbstart(file->f_path.dentry);
bend = fbend(file) = dbend(file->f_path.dentry);
for (bindex = bstart; bindex <= bend; bindex++) {
lower_dentry =
unionfs_lower_dentry_idx(file->f_path.dentry, bindex);
if (!lower_dentry)
continue;
dget(lower_dentry);
unionfs_mntget(file->f_path.dentry, bindex);
mnt = unionfs_lower_mnt_idx(file->f_path.dentry, bindex);
lower_file = dentry_open(lower_dentry, mnt, file->f_flags,
current_cred());
if (IS_ERR(lower_file))
return PTR_ERR(lower_file);
unionfs_set_lower_file_idx(file, bindex, lower_file);
/*
* The branchget goes after the open, because otherwise
* we would miss the reference on release.
*/
branchget(inode->i_sb, bindex);
}
return 0;
}
/* open all lower files for a given file */
static int open_all_files(struct file *file)
{
int bindex, bstart, bend, err = 0;
struct file *lower_file;
struct dentry *lower_dentry;
struct dentry *dentry = file->f_path.dentry;
struct super_block *sb = dentry->d_sb;
bstart = dbstart(dentry);
bend = dbend(dentry);
for (bindex = bstart; bindex <= bend; bindex++) {
lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
if (!lower_dentry)
continue;
dget(lower_dentry);
unionfs_mntget(dentry, bindex);
branchget(sb, bindex);
lower_file =
dentry_open(lower_dentry,
unionfs_lower_mnt_idx(dentry, bindex),
file->f_flags, current_cred());
if (IS_ERR(lower_file)) {
branchput(sb, bindex);
err = PTR_ERR(lower_file);
goto out;
} else {
unionfs_set_lower_file_idx(file, bindex, lower_file);
}
}
out:
return err;
}
/* perform a delayed copyup of a read-write file on a read-only branch */
static int do_delayed_copyup(struct file *file, struct dentry *parent)
{
int bindex, bstart, bend, err = 0;
struct dentry *dentry = file->f_path.dentry;
struct inode *parent_inode = parent->d_inode;
bstart = fbstart(file);
bend = fbend(file);
BUG_ON(!S_ISREG(dentry->d_inode->i_mode));
unionfs_check_file(file);
for (bindex = bstart - 1; bindex >= 0; bindex--) {
if (!d_deleted(dentry))
err = copyup_file(parent_inode, file, bstart,
bindex,
i_size_read(dentry->d_inode));
else
err = copyup_deleted_file(file, dentry, parent,
bstart, bindex);
/* if succeeded, set lower open-file flags and break */
if (!err) {
struct file *lower_file;
lower_file = unionfs_lower_file_idx(file, bindex);
lower_file->f_flags = file->f_flags;
break;
}
}
if (err || (bstart <= fbstart(file)))
goto out;
bend = fbend(file);
for (bindex = bstart; bindex <= bend; bindex++) {
if (unionfs_lower_file_idx(file, bindex)) {
branchput(dentry->d_sb, bindex);
fput(unionfs_lower_file_idx(file, bindex));
unionfs_set_lower_file_idx(file, bindex, NULL);
}
}
path_put_lowers(dentry, bstart, bend, false);
iput_lowers(dentry->d_inode, bstart, bend, false);
/* for reg file, we only open it "once" */
fbend(file) = fbstart(file);
dbend(dentry) = dbstart(dentry);
ibend(dentry->d_inode) = ibstart(dentry->d_inode);
out:
unionfs_check_file(file);
return err;
}
/*
* This function creates a copy of a file represented by 'file' which
* currently resides in branch 'bstart' to branch 'new_bindex.' The copy
* will be named "name".
*/
int copyup_named_file(struct inode *dir, struct file *file, char *name,
int bstart, int new_bindex, loff_t len)
{
int err = 0;
struct file *output_file = NULL;
err = copyup_dentry(dir, file->f_path.dentry, bstart, new_bindex,
name, strlen(name), &output_file, len);
if (!err) {
fbstart(file) = new_bindex;
unionfs_set_lower_file_idx(file, new_bindex, output_file);
}
return err;
}
/*
* This function creates a copy of a file represented by 'file' which
* currently resides in branch 'bstart' to branch 'new_bindex'.
*/
int copyup_file(struct inode *dir, struct file *file, int bstart,
int new_bindex, loff_t len)
{
int err = 0;
struct file *output_file = NULL;
struct dentry *dentry = file->f_path.dentry;
err = copyup_dentry(dir, dentry, bstart, new_bindex,
dentry->d_name.name, dentry->d_name.len,
&output_file, len);
if (!err) {
fbstart(file) = new_bindex;
unionfs_set_lower_file_idx(file, new_bindex, output_file);
}
return err;
}
/*
* release all lower object references & free the file info structure
*
* No need to grab sb info's rwsem.
*/
int unionfs_file_release(struct inode *inode, struct file *file)
{
struct file *lower_file = NULL;
struct unionfs_file_info *fileinfo;
struct unionfs_inode_info *inodeinfo;
struct super_block *sb = inode->i_sb;
struct dentry *dentry = file->f_path.dentry;
struct dentry *parent;
int bindex, bstart, bend;
int fgen, err = 0;
/*
* Since mm/memory.c:might_fault() (under PROVE_LOCKING) was
* modified in 2.6.29-rc1 to call might_lock_read on mmap_sem, this
* has been causing false positives in file system stacking layers.
* In particular, our ->mmap is called after sys_mmap2 already holds
* mmap_sem, then we lock our own mutexes; but earlier, it's
* possible for lockdep to have locked our mutexes first, and then
* we call a lower ->readdir which could call might_fault. The
* different ordering of the locks is what lockdep complains about
* -- unnecessarily. Therefore, we have no choice but to tell
* lockdep to temporarily turn off lockdep here. Note: the comments
* inside might_sleep also suggest that it would have been
* nicer to only annotate paths that needs that might_lock_read.
*/
lockdep_off();
unionfs_read_lock(sb, UNIONFS_SMUTEX_PARENT);
parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
/*
* We try to revalidate, but the VFS ignores return return values
* from file->release, so we must always try to succeed here,
* including to do the kfree and dput below. So if revalidation
* failed, all we can do is print some message and keep going.
*/
err = unionfs_file_revalidate(file, parent,
UNIONFS_F(file)->wrote_to_file);
if (!err)
unionfs_check_file(file);
fileinfo = UNIONFS_F(file);
BUG_ON(file->f_path.dentry->d_inode != inode);
inodeinfo = UNIONFS_I(inode);
/* fput all the lower files */
fgen = atomic_read(&fileinfo->generation);
bstart = fbstart(file);
bend = fbend(file);
for (bindex = bstart; bindex <= bend; bindex++) {
lower_file = unionfs_lower_file_idx(file, bindex);
if (lower_file) {
unionfs_set_lower_file_idx(file, bindex, NULL);
fput(lower_file);
branchput(sb, bindex);
}
/* if there are no more refs to the dentry, dput it */
if (d_deleted(dentry)) {
dput(unionfs_lower_dentry_idx(dentry, bindex));
unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
}
}
kfree(fileinfo->lower_files);
kfree(fileinfo->saved_branch_ids);
if (fileinfo->rdstate) {
fileinfo->rdstate->access = jiffies;
spin_lock(&inodeinfo->rdlock);
inodeinfo->rdcount++;
list_add_tail(&fileinfo->rdstate->cache,
&inodeinfo->readdircache);
mark_inode_dirty(inode);
spin_unlock(&inodeinfo->rdlock);
fileinfo->rdstate = NULL;
}
kfree(fileinfo);
unionfs_unlock_dentry(dentry);
unionfs_unlock_parent(dentry, parent);
unionfs_read_unlock(sb);
lockdep_on();
return err;
}
