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| author | Al Viro <viro@zeniv.linux.org.uk> | 2013-06-11 08:34:36 +0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-06-29 12:57:11 +0400 |
| commit | f4e0c30c191f87851c4a53454abb55ee276f4a7e (patch) | |
| tree | 8bdb4f81dea303f93f1d646034653c8af3fba323 | |
| parent | 60545d0d4610b02e55f65d141c95b18ccf855b6e (diff) | |
| download | op-kernel-dev-f4e0c30c191f87851c4a53454abb55ee276f4a7e.zip op-kernel-dev-f4e0c30c191f87851c4a53454abb55ee276f4a7e.tar.gz | |
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.c | 4 | ||||
| -rw-r--r-- | fs/namei.c | 16 | ||||
| -rw-r--r-- | include/linux/fs.h | 1 |
3 files changed, 18 insertions, 3 deletions
@@ -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++; } @@ -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 dd6615f..ab11c44 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) |
