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authorLinus Torvalds <torvalds@linux-foundation.org>2014-04-04 14:03:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-04 14:03:05 -0700
commit7df934526c0b3775613502dcd19ab6d2da8cce1e (patch)
tree01e6a4ea20c676228f4acefc6ae776d2e52072db /fs/inode.c
parent3c83e61e67256e0bb08c46cc2db43b58fd617251 (diff)
parentbd42998a6bcb9b1708dac9ca9876e3d304c16f3d (diff)
Merge branch 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
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()
Diffstat (limited to 'fs/inode.c')
-rw-r--r--fs/inode.c25
1 files changed, 12 insertions, 13 deletions
diff --git a/fs/inode.c b/fs/inode.c
index e6905152c39f..fb59ba7967f1 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -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);

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