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linux-sg2042
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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>
This commit is contained in:
Al Viro 2013-06-11 08:34:36 +04:00
parent 60545d0d46
commit f4e0c30c19
3 changed files with 18 additions and 3 deletions
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4
fs/inode.c
View File

@ -333,8 +333,10 @@ EXPORT_SYMBOL(set_nlink);
*/ */
void inc_nlink(struct inode *inode) 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); atomic_long_dec(&inode->i_sb->s_remove_count);
}
inode->__i_nlink++; inode->__i_nlink++;
} }

16
fs/namei.c
View File

@ -2948,8 +2948,14 @@ static int do_tmpfile(int dfd, struct filename *pathname,
if (error) if (error)
goto out2; goto out2;
error = open_check_o_direct(file); error = open_check_o_direct(file);
if (error) if (error) {
fput(file); 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: out2:
mnt_drop_write(nd->path.mnt); mnt_drop_write(nd->path.mnt);
out: out:
@ -3628,12 +3634,18 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
mutex_lock(&inode->i_mutex); mutex_lock(&inode->i_mutex);
/* Make sure we don't allow creating hardlink to an unlinked file */ /* 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; error = -ENOENT;
else if (max_links && inode->i_nlink >= max_links) else if (max_links && inode->i_nlink >= max_links)
error = -EMLINK; error = -EMLINK;
else else
error = dir->i_op->link(old_dentry, dir, new_dentry); 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); mutex_unlock(&inode->i_mutex);
if (!error) if (!error)
fsnotify_link(dir, inode, new_dentry); fsnotify_link(dir, inode, new_dentry);

1
include/linux/fs.h
View File

@ -1744,6 +1744,7 @@ struct super_operations {
#define I_REFERENCED (1 << 8) #define I_REFERENCED (1 << 8)
#define __I_DIO_WAKEUP 9 #define __I_DIO_WAKEUP 9
#define I_DIO_WAKEUP (1 << I_DIO_WAKEUP) #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) #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)