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authorAl Viro <viro@zeniv.linux.org.uk>2013-06-11 08:34:36 +0400
committerAl Viro <viro@zeniv.linux.org.uk>2013-06-29 12:57:11 +0400
commitf4e0c30c191f87851c4a53454abb55ee276f4a7e (patch)
tree8bdb4f81dea303f93f1d646034653c8af3fba323
parent60545d0d4610b02e55f65d141c95b18ccf855b6e (diff)
allow the temp files created by open() to be linked to
O_TMPFILE | O_CREAT => linkat() with AT_SYMLINK_FOLLOW and /proc/self/fd/<n> as oldpath (i.e. flink()) will create a link O_TMPFILE | O_CREAT | O_EXCL => ENOENT on attempt to link those guys Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/inode.c4
-rw-r--r--fs/namei.c16
-rw-r--r--include/linux/fs.h1
3 files changed, 18 insertions, 3 deletions
diff --git a/fs/inode.c b/fs/inode.c
index 00d5fc3b86e1..d6dfb09c8280 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -333,8 +333,10 @@ EXPORT_SYMBOL(set_nlink);
*/
void inc_nlink(struct inode *inode)
{
- if (WARN_ON(inode->i_nlink == 0))
+ if (unlikely(inode->i_nlink == 0)) {
+ WARN_ON(!(inode->i_state & I_LINKABLE));
atomic_long_dec(&inode->i_sb->s_remove_count);
+ }
inode->__i_nlink++;
}
diff --git a/fs/namei.c b/fs/namei.c
index 778e253e3d48..66998b06d822 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2948,8 +2948,14 @@ static int do_tmpfile(int dfd, struct filename *pathname,
if (error)
goto out2;
error = open_check_o_direct(file);
- if (error)
+ if (error) {
fput(file);
+ } else if (!(op->open_flag & O_EXCL)) {
+ struct inode *inode = file_inode(file);
+ spin_lock(&inode->i_lock);
+ inode->i_state |= I_LINKABLE;
+ spin_unlock(&inode->i_lock);
+ }
out2:
mnt_drop_write(nd->path.mnt);
out:
@@ -3628,12 +3634,18 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
mutex_lock(&inode->i_mutex);
/* Make sure we don't allow creating hardlink to an unlinked file */
- if (inode->i_nlink == 0)
+ if (inode->i_nlink == 0 && !(inode->i_state & I_LINKABLE))
error = -ENOENT;
else if (max_links && inode->i_nlink >= max_links)
error = -EMLINK;
else
error = dir->i_op->link(old_dentry, dir, new_dentry);
+
+ if (!error && (inode->i_state & I_LINKABLE)) {
+ spin_lock(&inode->i_lock);
+ inode->i_state &= ~I_LINKABLE;
+ spin_unlock(&inode->i_lock);
+ }
mutex_unlock(&inode->i_mutex);
if (!error)
fsnotify_link(dir, inode, new_dentry);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index dd6615f0fd13..ab11c44b0697 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1744,6 +1744,7 @@ struct super_operations {
#define I_REFERENCED (1 << 8)
#define __I_DIO_WAKEUP 9
#define I_DIO_WAKEUP (1 << I_DIO_WAKEUP)
+#define I_LINKABLE (1 << 10)
#define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)