On Fri, Feb 07, 2014 at 05:49:05PM +0100, Miklos Szeredi wrote:
> From: Miklos Szeredi <mszer...@suse.cz>
>
> lock_two_nondirectories warned if either of its args was a directory.
> Instead just ignore the directory args. This is needed for locking in
> cross rename.
>
> Signed-off-by: Miklos Szeredi <mszer...@suse.cz>
> ---
> fs/inode.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 4bcdad3c9361..763010771cf4 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -944,18 +944,21 @@ EXPORT_SYMBOL(unlock_new_inode);
>
> /**
> * lock_two_nondirectories - take two i_mutexes on non-directory objects
> + *
> + * If either or both arguments are directories, then ignore those.
> + * Therefore zero, one or two objects may be locked by this function.
> + *
> * @inode1: first inode to lock
> * @inode2: second inode to lock
> */
> void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
> {
> - WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
> - if (inode1 == inode2 || !inode2) {
> + if (S_ISDIR(inode1->i_mode)) {
> + if (inode2 && !S_ISDIR(inode2->i_mode))
> + mutex_lock(&inode2->i_mutex);
> + } else if (inode1 == inode2 || !inode2 || S_ISDIR(inode2->i_mode)) {
> mutex_lock(&inode1->i_mutex);
> - return;
> - }
> - WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
> - if (inode1 < inode2) {
> + } else if (inode1 < inode2) {
> mutex_lock(&inode1->i_mutex);
> mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
> } else {
Nit: I find the conditionals here a little complicated.
Would something like this be clearer? (Untested):
if (inode1 > inode2)
swap(inode1, inode2);
if (inode1 && !S_ISDIR(inode1->i_mode))
mutex_lock(&inode1->i_mutex);
if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
--b.
diff --git a/fs/inode.c b/fs/inode.c
index 4bcdad3..94e41c8 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -944,24 +944,23 @@ EXPORT_SYMBOL(unlock_new_inode);
/**
* lock_two_nondirectories - take two i_mutexes on non-directory objects
+ *
+ * Lock any non-NULL argument that is not a directory.
+ * Zero, one or two objects may be locked by this function.
+ *
* @inode1: first inode to lock
* @inode2: second inode to lock
*/
void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
- WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
- if (inode1 == inode2 || !inode2) {
- mutex_lock(&inode1->i_mutex);
- return;
- }
- WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
- if (inode1 < inode2) {
+ if (inode1 > inode2)
+ swap(inode1, inode2);
+
+ if (inode1 && !S_ISDIR(inode1->i_mode))
mutex_lock(&inode1->i_mutex);
+
+ if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
- } else {
- mutex_lock(&inode2->i_mutex);
- mutex_lock_nested(&inode1->i_mutex, I_MUTEX_NONDIR2);
- }
}
EXPORT_SYMBOL(lock_two_nondirectories);
@@ -972,8 +971,9 @@ EXPORT_SYMBOL(lock_two_nondirectories);
*/
void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
- mutex_unlock(&inode1->i_mutex);
- if (inode2 && inode2 != inode1)
+ if (inode1 && !S_ISDIR(inode1->i_mode))
+ mutex_unlock(&inode1->i_mutex);
+ if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
mutex_unlock(&inode2->i_mutex);
}
EXPORT_SYMBOL(unlock_two_nondirectories);
--
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