Union FS. Fix the unlink() method. What was I thinking
This commit is contained in:
Gregory Nutt
parent
884f3cdf74
commit
fe5e61960b
@ -92,7 +92,7 @@ struct unionfs_inode_s
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struct unionfs_mountpt_s ui_fs[2]; /* Contained file systems */
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sem_t ui_exclsem; /* Enforces mutually exclusive access */
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int16_t ui_nopen; /* Number of open references */
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bool ui_unhooked; /* Driver is unlinked or unbound */
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bool ui_unmounted; /* File system has been unmounted */
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};
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/* This structure descries one opened file */
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@ -124,6 +124,8 @@ static int unionfs_trymkdir(FAR struct inode *inode,
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mode_t mode);
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static int unionfs_tryrmdir(FAR struct inode *inode,
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FAR const char *relpath, FAR const char *prefix);
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static int unionfs_tryunlink(FAR struct inode *inode,
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FAR const char *relpath, FAR const char *prefix);
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static int unionfs_tryrename(FAR struct inode *mountpt,
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FAR const char *oldrelpath, FAR const char *newrelpath,
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FAR const char *prefix);
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@ -137,7 +139,6 @@ static int unionfs_trystatfile(FAR struct inode *inode,
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static FAR char *unionfs_relpath(FAR const char *path,
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FAR const char *name);
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static void unionfs_unhooked(FAR struct unionfs_inode_s *ui);
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static void unionfs_destroy(FAR struct unionfs_inode_s *ui);
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/* Operations on opened files (with struct file) */
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@ -552,7 +553,7 @@ static int unionfs_tryrmdir(FAR struct inode *inode, FAR const char *relpath,
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return -ENOENT;
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}
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/* Yes.. Try to create the directory */
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/* Yes.. Try to remove the directory */
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ops = inode->u.i_mops;
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if (!ops->rmdir)
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@ -563,6 +564,38 @@ static int unionfs_tryrmdir(FAR struct inode *inode, FAR const char *relpath,
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return ops->rmdir(inode, trypath);
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}
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/****************************************************************************
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* Name: unionfs_tryunlink
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****************************************************************************/
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static int unionfs_tryunlink(FAR struct inode *inode,
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FAR const char *relpath,
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FAR const char *prefix)
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{
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FAR const struct mountpt_operations *ops;
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FAR const char *trypath;
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/* Is this path valid on this file system? */
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trypath = unionfs_trypath(relpath, prefix);
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if (trypath == NULL)
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{
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/* No.. return -ENOENT */
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return -ENOENT;
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}
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/* Yes.. Try to unlink the file */
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ops = inode->u.i_mops;
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if (!ops->unlink)
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{
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return -ENOSYS;
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}
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return ops->unlink(inode, trypath);
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}
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/****************************************************************************
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* Name: unionfs_relpath
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****************************************************************************/
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@ -609,29 +642,6 @@ static FAR char *unionfs_relpath(FAR const char *path, FAR const char *name)
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}
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}
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/****************************************************************************
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* Name: unionfs_unhooked
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****************************************************************************/
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static void unionfs_unhooked(FAR struct unionfs_inode_s *ui)
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{
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fvdbg("Entry\n");
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DEBUGASSERT(ui);
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/* Mark the file system as unhooked (unlinked or unmounted) */
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ui->ui_unhooked = true;
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/* If there are no open references, then we can destroy the file system
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* now.
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*/
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if (ui->ui_nopen <= 0)
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{
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unionfs_destroy(ui);
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}
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}
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/****************************************************************************
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* Name: unionfs_destroy
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****************************************************************************/
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@ -787,11 +797,11 @@ static int unionfs_close(FAR struct file *filep)
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}
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/* Decrement the count of open reference. If that count would go to zero
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* and if the file system has been unmounted or if the mountpoint has been
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* unlinked, then destroy the file system now.
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* and if the file system has been unmounted, then destroy the file system
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* now.
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*/
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if (--ui->ui_nopen <= 0 && ui->ui_unhooked)
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if (--ui->ui_nopen <= 0 && ui->ui_unmounted)
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{
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unionfs_destroy(ui);
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}
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@ -1348,11 +1358,11 @@ static int unionfs_closedir(FAR struct inode *mountpt,
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fu->fu_lower[1] = NULL;
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/* Decrement the count of open reference. If that count would go to zero
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* and if the file system has been unmounted or if the mountpoint has been
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* unlinked, then destroy the file system now.
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* and if the file system has been unmounted, then destroy the file system
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* now.
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*/
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if (--ui->ui_nopen <= 0 && ui->ui_unhooked)
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if (--ui->ui_nopen <= 0 && ui->ui_unmounted)
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{
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unionfs_destroy(ui);
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}
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@ -1563,7 +1573,33 @@ static int unionfs_rewinddir(struct inode *mountpt, struct fs_dirent_s *dir)
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static int unionfs_unbind(FAR void *handle, FAR struct inode **blkdriver,
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unsigned int flags)
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{
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unionfs_unhooked((FAR struct unionfs_inode_s *)handle);
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FAR struct unionfs_inode_s *ui;
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fvdbg("Entry\n");
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/* Recover the union file system data from the struct inode instance */
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DEBUGASSERT(handle != NULL);
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ui = (FAR struct unionfs_inode_s *)handle;
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/* Get exclusive access to the file system data structures */
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(void)unionfs_semtake(ui, true);
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/* Mark the file system as unmounted. */
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ui->ui_unmounted = true;
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/* If there are no open references, then we can destroy the file system
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* now.
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*/
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if (ui->ui_nopen <= 0)
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{
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unionfs_destroy(ui);
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}
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unionfs_semgive(ui);
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return OK;
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}
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@ -1688,6 +1724,8 @@ static int unionfs_unlink(FAR struct inode *mountpt,
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FAR const char *relpath)
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{
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FAR struct unionfs_inode_s *ui;
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FAR struct unionfs_mountpt_s *um;
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struct stat buf;
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int ret;
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fdbg("relpath: %s\n", relpath);
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@ -1705,11 +1743,46 @@ static int unionfs_unlink(FAR struct inode *mountpt,
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return ret;
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}
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/* Unhook/unlink the union file system */
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/* Check if some exists at this path on file system 1. This might be
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* a file or a directory*/
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um = &ui->ui_fs[0];
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ret = unionfs_trystat(um->um_node, relpath, um->um_prefix, &buf);
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if (ret >= 0)
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{
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/* Yes.. Try to unlink the file on file system 1 (perhaps exposing
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* a file of the same name on file system 2). This would fail
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* with -ENOSYS if file system 1 is a read-only only file system or
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* -EISDIR if the path is not a file.
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*/
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ret = unionfs_tryunlink(um->um_node, relpath, um->um_prefix);
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}
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/* There is nothing at this path on file system 1 */
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else
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{
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/* Check if the file exists with with name on file system 2. The only
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* reason that we check here is so that we can return the more
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* meaningful -ENOSYS if file system 2 is a read-only file system.
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*/
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um = &ui->ui_fs[1];
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ret = unionfs_trystat(um->um_node, relpath, um->um_prefix, &buf);
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if (ret >= 0)
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{
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/* Yes.. Try to unlink the file on file system 1. This would fail
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* with -ENOSYS if file system 2 is a read-only only file system or
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* -EISDIR if the path is not a file.
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* */
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ret = unionfs_tryunlink(um->um_node, relpath, um->um_prefix);
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}
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}
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unionfs_unhooked((FAR struct unionfs_inode_s *)mountpt->i_private);
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unionfs_semgive(ui);
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return OK;
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return ret;
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}
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/****************************************************************************
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@ -1797,7 +1870,7 @@ static int unionfs_rmdir(FAR struct inode *mountpt, FAR const char *relpath)
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FAR struct unionfs_inode_s *ui;
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FAR struct unionfs_mountpt_s *um;
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int tmp;
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int ret = -ENOENT;
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int ret;
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fdbg("relpath: %s\n", relpath);
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@ -1814,6 +1887,8 @@ static int unionfs_rmdir(FAR struct inode *mountpt, FAR const char *relpath)
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return ret;
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}
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ret = -ENOENT;
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/* We really don't know any better so we will try to remove the directory
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* from both file systems.
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*/
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