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| author | Al Viro <viro@zeniv.linux.org.uk> | 2012-02-06 12:45:27 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-03-20 21:29:32 -0400 |
| commit | 8de52778798fe39660a8d6b26f290e0c93202761 (patch) | |
| tree | 56384beb7863c1f338f2b66b509bf58eea5a99c2 /fs/namei.c | |
| parent | c16fa4f2ad19908a47c63d8fa436a1178438c7e7 (diff) | |
| download | lwn-8de52778798fe39660a8d6b26f290e0c93202761.tar.gz lwn-8de52778798fe39660a8d6b26f290e0c93202761.zip | |
vfs: check i_nlink limits in vfs_{mkdir,rename_dir,link}
New field of struct super_block - ->s_max_links. Maximal allowed
value of ->i_nlink or 0; in the latter case all checks still need
to be done in ->link/->mkdir/->rename instances. Note that this
limit applies both to directoris and to non-directories.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/fs/namei.c b/fs/namei.c index 46ea9cc16647..a0b82762e8fc 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2569,6 +2569,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { int error = may_create(dir, dentry); + unsigned max_links = dir->i_sb->s_max_links; if (error) return error; @@ -2581,6 +2582,9 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) if (error) return error; + if (max_links && dir->i_nlink >= max_links) + return -EMLINK; + error = dir->i_op->mkdir(dir, dentry, mode); if (!error) fsnotify_mkdir(dir, dentry); @@ -2911,6 +2915,7 @@ SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newn int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) { struct inode *inode = old_dentry->d_inode; + unsigned max_links = dir->i_sb->s_max_links; int error; if (!inode) @@ -2941,6 +2946,8 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de /* Make sure we don't allow creating hardlink to an unlinked file */ if (inode->i_nlink == 0) error = -ENOENT; + else if (max_links && inode->i_nlink >= max_links) + error = -EMLINK; else error = dir->i_op->link(old_dentry, dir, new_dentry); mutex_unlock(&inode->i_mutex); @@ -3050,6 +3057,7 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, { int error = 0; struct inode *target = new_dentry->d_inode; + unsigned max_links = new_dir->i_sb->s_max_links; /* * If we are going to change the parent - check write permissions, @@ -3073,6 +3081,11 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry)) goto out; + error = -EMLINK; + if (max_links && !target && new_dir != old_dir && + new_dir->i_nlink >= max_links) + goto out; + if (target) shrink_dcache_parent(new_dentry); error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); |