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Subject[PATCH 12/42] Unionfs: common file copyup/revalidation operations
Date
Includes open, ioctl, and flush operations.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
---
fs/unionfs/commonfops.c | 827 +++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 827 insertions(+), 0 deletions(-)
create mode 100644 fs/unionfs/commonfops.c

diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
new file mode 100644
index 0000000..f714e2f
--- /dev/null
+++ b/fs/unionfs/commonfops.c
@@ -0,0 +1,827 @@
+/*
+ * Copyright (c) 2003-2007 Erez Zadok
+ * Copyright (c) 2003-2006 Charles P. Wright
+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
+ * Copyright (c) 2005-2006 Junjiro Okajima
+ * Copyright (c) 2005 Arun M. Krishnakumar
+ * Copyright (c) 2004-2006 David P. Quigley
+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
+ * Copyright (c) 2003 Puja Gupta
+ * Copyright (c) 2003 Harikesavan Krishnan
+ * Copyright (c) 2003-2007 Stony Brook University
+ * Copyright (c) 2003-2007 The Research Foundation of SUNY
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include "union.h"
+
+/*
+ * 1) Copyup the file
+ * 2) Rename the file to '.unionfs<original inode#><counter>' - obviously
+ * stolen from NFS's silly rename
+ */
+static int copyup_deleted_file(struct file *file, struct dentry *dentry,
+ int bstart, int bindex)
+{
+ static unsigned int counter;
+ const int i_inosize = sizeof(dentry->d_inode->i_ino) * 2;
+ const int countersize = sizeof(counter) * 2;
+ const int nlen = sizeof(".unionfs") + i_inosize + countersize - 1;
+ char name[nlen + 1];
+ int err;
+ struct dentry *tmp_dentry = NULL;
+ struct dentry *lower_dentry;
+ struct dentry *lower_dir_dentry = NULL;
+
+ lower_dentry = unionfs_lower_dentry_idx(dentry, bstart);
+
+ sprintf(name, ".unionfs%*.*lx",
+ i_inosize, i_inosize, lower_dentry->d_inode->i_ino);
+
+ /*
+ * Loop, looking for an unused temp name to copyup to.
+ *
+ * It's somewhat silly that we look for a free temp tmp name in the
+ * source branch (bstart) instead of the dest branch (bindex), where
+ * the final name will be created. We _will_ catch it if somehow
+ * the name exists in the dest branch, but it'd be nice to catch it
+ * sooner than later.
+ */
+retry:
+ tmp_dentry = NULL;
+ do {
+ char *suffix = name + nlen - countersize;
+
+ dput(tmp_dentry);
+ counter++;
+ sprintf(suffix, "%*.*x", countersize, countersize, counter);
+
+ pr_debug("unionfs: trying to rename %s to %s\n",
+ dentry->d_name.name, name);
+
+ tmp_dentry = lookup_one_len(name, lower_dentry->d_parent,
+ nlen);
+ if (IS_ERR(tmp_dentry)) {
+ err = PTR_ERR(tmp_dentry);
+ goto out;
+ }
+ } while (tmp_dentry->d_inode != NULL); /* need negative dentry */
+ dput(tmp_dentry);
+
+ err = copyup_named_file(dentry->d_parent->d_inode, file, name, bstart,
+ bindex,
+ i_size_read(file->f_path.dentry->d_inode));
+ if (err) {
+ if (unlikely(err == -EEXIST))
+ goto retry;
+ goto out;
+ }
+
+ /* bring it to the same state as an unlinked file */
+ lower_dentry = unionfs_lower_dentry_idx(dentry, dbstart(dentry));
+ if (!unionfs_lower_inode_idx(dentry->d_inode, bindex)) {
+ atomic_inc(&lower_dentry->d_inode->i_count);
+ unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
+ lower_dentry->d_inode);
+ }
+ lower_dir_dentry = lock_parent(lower_dentry);
+ err = vfs_unlink(lower_dir_dentry->d_inode, lower_dentry);
+ unlock_dir(lower_dir_dentry);
+
+out:
+ if (!err)
+ unionfs_check_dentry(dentry);
+ return err;
+}
+
+/*
+ * put all references held by upper struct file and free lower file pointer
+ * array
+ */
+static void cleanup_file(struct file *file)
+{
+ int bindex, bstart, bend;
+ struct file **lower_files;
+ struct file *lower_file;
+ struct super_block *sb = file->f_path.dentry->d_sb;
+
+ lower_files = UNIONFS_F(file)->lower_files;
+ bstart = fbstart(file);
+ bend = fbend(file);
+
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ int i; /* holds (possibly) updated branch index */
+ int old_bid;
+
+ lower_file = unionfs_lower_file_idx(file, bindex);
+ if (!lower_file)
+ continue;
+
+ /*
+ * Find new index of matching branch with an open
+ * file, since branches could have been added or
+ * deleted causing the one with open files to shift.
+ */
+ old_bid = UNIONFS_F(file)->saved_branch_ids[bindex];
+ i = branch_id_to_idx(sb, old_bid);
+ if (unlikely(i < 0)) {
+ printk(KERN_ERR "unionfs: no superblock for "
+ "file %p\n", file);
+ continue;
+ }
+
+ /* decrement count of open files */
+ branchput(sb, i);
+ /*
+ * fput will perform an mntput for us on the correct branch.
+ * Although we're using the file's old branch configuration,
+ * bindex, which is the old index, correctly points to the
+ * right branch in the file's branch list. In other words,
+ * we're going to mntput the correct branch even if branches
+ * have been added/removed.
+ */
+ fput(lower_file);
+ UNIONFS_F(file)->lower_files[bindex] = NULL;
+ UNIONFS_F(file)->saved_branch_ids[bindex] = -1;
+ }
+
+ UNIONFS_F(file)->lower_files = NULL;
+ kfree(lower_files);
+ kfree(UNIONFS_F(file)->saved_branch_ids);
+ /* set to NULL because caller needs to know if to kfree on error */
+ UNIONFS_F(file)->saved_branch_ids = NULL;
+}
+
+/* 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);
+ if (IS_ERR(lower_file)) {
+ err = PTR_ERR(lower_file);
+ goto out;
+ } else {
+ unionfs_set_lower_file_idx(file, bindex, lower_file);
+ }
+ }
+out:
+ return err;
+}
+
+/* open the highest priority file for a given upper file */
+static int open_highest_file(struct file *file, bool willwrite)
+{
+ int bindex, bstart, bend, err = 0;
+ struct file *lower_file;
+ struct dentry *lower_dentry;
+ struct dentry *dentry = file->f_path.dentry;
+ struct inode *parent_inode = dentry->d_parent->d_inode;
+ struct super_block *sb = dentry->d_sb;
+
+ bstart = dbstart(dentry);
+ bend = dbend(dentry);
+
+ lower_dentry = unionfs_lower_dentry(dentry);
+ if (willwrite && IS_WRITE_FLAG(file->f_flags) && is_robranch(dentry)) {
+ for (bindex = bstart - 1; bindex >= 0; bindex--) {
+ err = copyup_file(parent_inode, file, bstart, bindex,
+ i_size_read(dentry->d_inode));
+ if (!err)
+ break;
+ }
+ atomic_set(&UNIONFS_F(file)->generation,
+ atomic_read(&UNIONFS_I(dentry->d_inode)->
+ generation));
+ goto out;
+ }
+
+ dget(lower_dentry);
+ unionfs_mntget(dentry, bstart);
+ lower_file = dentry_open(lower_dentry,
+ unionfs_lower_mnt_idx(dentry, bstart),
+ file->f_flags);
+ if (IS_ERR(lower_file)) {
+ err = PTR_ERR(lower_file);
+ goto out;
+ }
+ branchget(sb, bstart);
+ unionfs_set_lower_file(file, lower_file);
+ /* Fix up the position. */
+ lower_file->f_pos = file->f_pos;
+
+ memcpy(&lower_file->f_ra, &file->f_ra, sizeof(struct file_ra_state));
+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)
+{
+ int bindex, bstart, bend, err = 0;
+ struct dentry *dentry = file->f_path.dentry;
+ struct inode *parent_inode = dentry->d_parent->d_inode;
+
+ bstart = fbstart(file);
+ bend = fbend(file);
+
+ BUG_ON(!S_ISREG(dentry->d_inode->i_mode));
+
+ unionfs_check_file(file);
+ unionfs_check_dentry(dentry);
+ 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, bstart,
+ bindex);
+
+ if (!err)
+ 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);
+ }
+ if (unionfs_lower_mnt_idx(dentry, bindex)) {
+ unionfs_mntput(dentry, bindex);
+ unionfs_set_lower_mnt_idx(dentry, bindex, NULL);
+ }
+ if (unionfs_lower_dentry_idx(dentry, bindex)) {
+ BUG_ON(!dentry->d_inode);
+ iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
+ unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
+ NULL);
+ dput(unionfs_lower_dentry_idx(dentry, bindex));
+ unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
+ }
+ }
+ /* for reg file, we only open it "once" */
+ fbend(file) = fbstart(file);
+ set_dbend(dentry, dbstart(dentry));
+ ibend(dentry->d_inode) = ibstart(dentry->d_inode);
+
+out:
+ unionfs_check_file(file);
+ unionfs_check_dentry(dentry);
+ return err;
+}
+
+/*
+ * Revalidate the struct file
+ * @file: file to revalidate
+ * @willwrite: true if caller may cause changes to the file; false otherwise.
+ */
+int unionfs_file_revalidate(struct file *file, bool willwrite)
+{
+ struct super_block *sb;
+ struct dentry *dentry;
+ int sbgen, fgen, dgen;
+ int bstart, bend;
+ int size;
+ int err = 0;
+
+ dentry = file->f_path.dentry;
+ unionfs_lock_dentry(dentry);
+ sb = dentry->d_sb;
+
+ /*
+ * First revalidate the dentry inside struct file,
+ * but not unhashed dentries.
+ */
+ if (unlikely(!d_deleted(dentry) &&
+ !__unionfs_d_revalidate_chain(dentry, NULL, willwrite))) {
+ err = -ESTALE;
+ goto out_nofree;
+ }
+
+ sbgen = atomic_read(&UNIONFS_SB(sb)->generation);
+ dgen = atomic_read(&UNIONFS_D(dentry)->generation);
+ fgen = atomic_read(&UNIONFS_F(file)->generation);
+
+ BUG_ON(sbgen > dgen);
+
+ /*
+ * There are two cases we are interested in. The first is if the
+ * generation is lower than the super-block. The second is if
+ * someone has copied up this file from underneath us, we also need
+ * to refresh things.
+ */
+ if (unlikely(!d_deleted(dentry) &&
+ (sbgen > fgen || dbstart(dentry) != fbstart(file)))) {
+ /* save orig branch ID */
+ int orig_brid =
+ UNIONFS_F(file)->saved_branch_ids[fbstart(file)];
+
+ /* First we throw out the existing files. */
+ cleanup_file(file);
+
+ /* Now we reopen the file(s) as in unionfs_open. */
+ bstart = fbstart(file) = dbstart(dentry);
+ bend = fbend(file) = dbend(dentry);
+
+ size = sizeof(struct file *) * sbmax(sb);
+ UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL);
+ if (unlikely(!UNIONFS_F(file)->lower_files)) {
+ err = -ENOMEM;
+ goto out;
+ }
+ size = sizeof(int) * sbmax(sb);
+ UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL);
+ if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ if (S_ISDIR(dentry->d_inode->i_mode)) {
+ /* We need to open all the files. */
+ err = open_all_files(file);
+ if (err)
+ goto out;
+ } else {
+ int new_brid;
+ /* We only open the highest priority branch. */
+ err = open_highest_file(file, willwrite);
+ if (err)
+ goto out;
+ new_brid = UNIONFS_F(file)->
+ saved_branch_ids[fbstart(file)];
+ if (unlikely(new_brid != orig_brid && sbgen > fgen)) {
+ /*
+ * If we re-opened the file on a different
+ * branch than the original one, and this
+ * was due to a new branch inserted, then
+ * update the mnt counts of the old and new
+ * branches accordingly.
+ */
+ unionfs_mntget(dentry, bstart);
+ unionfs_mntput(sb->s_root,
+ branch_id_to_idx(sb, orig_brid));
+ }
+ }
+ atomic_set(&UNIONFS_F(file)->generation,
+ atomic_read(
+ &UNIONFS_I(dentry->d_inode)->generation));
+ }
+
+ /* Copyup on the first write to a file on a readonly branch. */
+ if (willwrite && IS_WRITE_FLAG(file->f_flags) &&
+ !IS_WRITE_FLAG(unionfs_lower_file(file)->f_flags) &&
+ is_robranch(dentry)) {
+ pr_debug("unionfs: do delay copyup of \"%s\"\n",
+ dentry->d_name.name);
+ err = do_delayed_copyup(file);
+ }
+
+out:
+ if (err) {
+ kfree(UNIONFS_F(file)->lower_files);
+ kfree(UNIONFS_F(file)->saved_branch_ids);
+ }
+out_nofree:
+ if (!err)
+ unionfs_check_file(file);
+ unionfs_unlock_dentry(dentry);
+ return err;
+}
+
+/* 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);
+ 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;
+}
+
+/* unionfs_open helper function: open a file */
+static int __open_file(struct inode *inode, struct file *file)
+{
+ struct dentry *lower_dentry;
+ struct file *lower_file;
+ int lower_flags;
+ int bindex, bstart, bend;
+
+ lower_dentry = unionfs_lower_dentry(file->f_path.dentry);
+ lower_flags = file->f_flags;
+
+ bstart = fbstart(file) = dbstart(file->f_path.dentry);
+ bend = fbend(file) = dbend(file->f_path.dentry);
+
+ /*
+ * check for the permission for lower file. If the error is
+ * COPYUP_ERR, copyup the file.
+ */
+ if (lower_dentry->d_inode && is_robranch(file->f_path.dentry)) {
+ /*
+ * if the open will change the file, copy it up otherwise
+ * defer it.
+ */
+ if (lower_flags & O_TRUNC) {
+ int size = 0;
+ int err = -EROFS;
+
+ /* copyup the file */
+ for (bindex = bstart - 1; bindex >= 0; bindex--) {
+ err = copyup_file(
+ file->f_path.dentry->d_parent->d_inode,
+ file, bstart, bindex, size);
+ if (!err)
+ break;
+ }
+ return err;
+ } else {
+ lower_flags &= ~(OPEN_WRITE_FLAGS);
+ }
+ }
+
+ dget(lower_dentry);
+
+ /*
+ * dentry_open will decrement mnt refcnt if err.
+ * otherwise fput() will do an mntput() for us upon file close.
+ */
+ unionfs_mntget(file->f_path.dentry, bstart);
+ lower_file =
+ dentry_open(lower_dentry,
+ unionfs_lower_mnt_idx(file->f_path.dentry, bstart),
+ lower_flags);
+ if (IS_ERR(lower_file))
+ return PTR_ERR(lower_file);
+
+ unionfs_set_lower_file(file, lower_file);
+ branchget(inode->i_sb, bstart);
+
+ return 0;
+}
+
+int unionfs_open(struct inode *inode, struct file *file)
+{
+ int err = 0;
+ struct file *lower_file = NULL;
+ struct dentry *dentry = NULL;
+ int bindex = 0, bstart = 0, bend = 0;
+ int size;
+
+ unionfs_read_lock(inode->i_sb);
+
+ file->private_data =
+ kzalloc(sizeof(struct unionfs_file_info), GFP_KERNEL);
+ if (unlikely(!UNIONFS_F(file))) {
+ err = -ENOMEM;
+ goto out_nofree;
+ }
+ fbstart(file) = -1;
+ fbend(file) = -1;
+ atomic_set(&UNIONFS_F(file)->generation,
+ atomic_read(&UNIONFS_I(inode)->generation));
+
+ size = sizeof(struct file *) * sbmax(inode->i_sb);
+ UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL);
+ if (unlikely(!UNIONFS_F(file)->lower_files)) {
+ err = -ENOMEM;
+ goto out;
+ }
+ size = sizeof(int) * sbmax(inode->i_sb);
+ UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL);
+ if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ dentry = file->f_path.dentry;
+ unionfs_lock_dentry(dentry);
+
+ bstart = fbstart(file) = dbstart(dentry);
+ bend = fbend(file) = dbend(dentry);
+
+ /*
+ * open all directories and make the unionfs file struct point to
+ * these lower file structs
+ */
+ if (S_ISDIR(inode->i_mode))
+ err = __open_dir(inode, file); /* open a dir */
+ else
+ err = __open_file(inode, file); /* open a file */
+
+ /* freeing the allocated resources, and fput the opened files */
+ if (err) {
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ lower_file = unionfs_lower_file_idx(file, bindex);
+ if (!lower_file)
+ continue;
+
+ branchput(file->f_path.dentry->d_sb, bindex);
+ /* fput calls dput for lower_dentry */
+ fput(lower_file);
+ }
+ }
+
+ /* XXX: should this unlock be moved to the function bottom? */
+ unionfs_unlock_dentry(dentry);
+
+out:
+ if (err) {
+ kfree(UNIONFS_F(file)->lower_files);
+ kfree(UNIONFS_F(file)->saved_branch_ids);
+ kfree(UNIONFS_F(file));
+ }
+out_nofree:
+ unionfs_check_inode(inode);
+ if (!err) {
+ unionfs_check_file(file);
+ unionfs_check_dentry(file->f_path.dentry->d_parent);
+ }
+ unionfs_read_unlock(inode->i_sb);
+ 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;
+ int bindex, bstart, bend;
+ int fgen, err = 0;
+
+ unionfs_read_lock(sb);
+ /*
+ * Yes, we have to revalidate this file even if it's being released.
+ * This is important for open-but-unlinked files, as well as mmap
+ * support.
+ */
+ err = unionfs_file_revalidate(file, true);
+ if (unlikely(err))
+ goto out;
+ 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);
+
+ unionfs_lock_dentry(dentry);
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ lower_file = unionfs_lower_file_idx(file, bindex);
+
+ if (lower_file) {
+ 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);
+ }
+ }
+ unionfs_unlock_dentry(dentry);
+
+ 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);
+
+out:
+ unionfs_read_unlock(sb);
+ return err;
+}
+
+/* pass the ioctl to the lower fs */
+static long do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct file *lower_file;
+ int err;
+
+ lower_file = unionfs_lower_file(file);
+
+ err = -ENOTTY;
+ if (!lower_file || !lower_file->f_op)
+ goto out;
+ if (lower_file->f_op->unlocked_ioctl) {
+ err = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
+ } else if (lower_file->f_op->ioctl) {
+ lock_kernel();
+ err = lower_file->f_op->ioctl(
+ lower_file->f_path.dentry->d_inode,
+ lower_file, cmd, arg);
+ unlock_kernel();
+ }
+
+out:
+ return err;
+}
+
+/*
+ * return to user-space the branch indices containing the file in question
+ *
+ * We use fd_set and therefore we are limited to the number of the branches
+ * to FD_SETSIZE, which is currently 1024 - plenty for most people
+ */
+static int unionfs_ioctl_queryfile(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ int err = 0;
+ fd_set branchlist;
+ int bstart = 0, bend = 0, bindex = 0;
+ int orig_bstart, orig_bend;
+ struct dentry *dentry, *lower_dentry;
+ struct vfsmount *mnt;
+
+ dentry = file->f_path.dentry;
+ unionfs_lock_dentry(dentry);
+ orig_bstart = dbstart(dentry);
+ orig_bend = dbend(dentry);
+ err = unionfs_partial_lookup(dentry);
+ if (err)
+ goto out;
+ bstart = dbstart(dentry);
+ bend = dbend(dentry);
+
+ FD_ZERO(&branchlist);
+
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
+ if (!lower_dentry)
+ continue;
+ if (likely(lower_dentry->d_inode))
+ FD_SET(bindex, &branchlist);
+ /* purge any lower objects after partial_lookup */
+ if (bindex < orig_bstart || bindex > orig_bend) {
+ dput(lower_dentry);
+ unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
+ iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
+ unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
+ NULL);
+ mnt = unionfs_lower_mnt_idx(dentry, bindex);
+ if (!mnt)
+ continue;
+ unionfs_mntput(dentry, bindex);
+ unionfs_set_lower_mnt_idx(dentry, bindex, NULL);
+ }
+ }
+ /* restore original dentry's offsets */
+ set_dbstart(dentry, orig_bstart);
+ set_dbend(dentry, orig_bend);
+ ibstart(dentry->d_inode) = orig_bstart;
+ ibend(dentry->d_inode) = orig_bend;
+
+ err = copy_to_user((void __user *)arg, &branchlist, sizeof(fd_set));
+ if (unlikely(err))
+ err = -EFAULT;
+
+out:
+ unionfs_unlock_dentry(dentry);
+ return err < 0 ? err : bend;
+}
+
+long unionfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ long err;
+
+ unionfs_read_lock(file->f_path.dentry->d_sb);
+
+ err = unionfs_file_revalidate(file, true);
+ if (unlikely(err))
+ goto out;
+
+ /* check if asked for local commands */
+ switch (cmd) {
+ case UNIONFS_IOCTL_INCGEN:
+ /* Increment the superblock generation count */
+ pr_info("unionfs: incgen ioctl deprecated; "
+ "use \"-o remount,incgen\"\n");
+ err = -ENOSYS;
+ break;
+
+ case UNIONFS_IOCTL_QUERYFILE:
+ /* Return list of branches containing the given file */
+ err = unionfs_ioctl_queryfile(file, cmd, arg);
+ break;
+
+ default:
+ /* pass the ioctl down */
+ err = do_ioctl(file, cmd, arg);
+ break;
+ }
+
+out:
+ unionfs_check_file(file);
+ unionfs_read_unlock(file->f_path.dentry->d_sb);
+ return err;
+}
+
+int unionfs_flush(struct file *file, fl_owner_t id)
+{
+ int err = 0;
+ struct file *lower_file = NULL;
+ struct dentry *dentry = file->f_path.dentry;
+ int bindex, bstart, bend;
+
+ unionfs_read_lock(dentry->d_sb);
+
+ err = unionfs_file_revalidate(file, true);
+ if (unlikely(err))
+ goto out;
+ unionfs_check_file(file);
+
+ bstart = fbstart(file);
+ bend = fbend(file);
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ lower_file = unionfs_lower_file_idx(file, bindex);
+
+ if (lower_file && lower_file->f_op &&
+ lower_file->f_op->flush) {
+ err = lower_file->f_op->flush(lower_file, id);
+ if (err)
+ goto out;
+ }
+
+ }
+
+ /* on success, update our times */
+ unionfs_copy_attr_times(dentry->d_inode);
+ /* parent time could have changed too (async) */
+ unionfs_copy_attr_times(dentry->d_parent->d_inode);
+
+out:
+ unionfs_check_file(file);
+ unionfs_read_unlock(dentry->d_sb);
+ return err;
+}
--
1.5.2.2


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