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Merge branch 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

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Pull renameat2 system call from Miklos Szeredi:
 "This adds a new syscall, renameat2(), which is the same as renameat()
  but with a flags argument.

  The purpose of extending rename is to add cross-rename, a symmetric
  variant of rename, which exchanges the two files.  This allows
  interesting things, which were not possible before, for example
  atomically replacing a directory tree with a symlink, etc...  This
  also allows overlayfs and friends to operate on whiteouts atomically.

  Andy Lutomirski also suggested a "noreplace" flag, which disables the
  overwriting behavior of rename.

  These two flags, RENAME_EXCHANGE and RENAME_NOREPLACE are only
  implemented for ext4 as an example and for testing"

* 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ext4: add cross rename support
  ext4: rename: split out helper functions
  ext4: rename: move EMLINK check up
  ext4: rename: create ext4_renament structure for local vars
  vfs: add cross-rename
  vfs: lock_two_nondirectories: allow directory args
  security: add flags to rename hooks
  vfs: add RENAME_NOREPLACE flag
  vfs: add renameat2 syscall
  vfs: rename: use common code for dir and non-dir
  vfs: rename: move d_move() up
  vfs: add d_is_dir()
This commit is contained in:
Linus Torvalds
2014-04-04 14:03:05 -07:00
parent 3c83e61e67 bd42998a6b
commit 7df934526c
17 changed files with 660 additions and 330 deletions
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25
fs/inode.c
View File

@@ -944,24 +944,22 @@ 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 +970,9 @@ 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);