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https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
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VFS: Make more complete truncate operation available to CacheFiles
Make a more complete truncate operation available to CacheFiles (including security checks and suchlike) so that it can use this to clear invalidated cache files. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
parent
ef778e7ae6
commit
a02de96085
2 changed files with 28 additions and 23 deletions
50
fs/open.c
50
fs/open.c
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@ -61,33 +61,22 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
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return ret;
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}
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static long do_sys_truncate(const char __user *pathname, loff_t length)
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long vfs_truncate(struct path *path, loff_t length)
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{
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struct path path;
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struct inode *inode;
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int error;
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long error;
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error = -EINVAL;
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if (length < 0) /* sorry, but loff_t says... */
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goto out;
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error = user_path(pathname, &path);
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if (error)
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goto out;
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inode = path.dentry->d_inode;
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inode = path->dentry->d_inode;
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/* For directories it's -EISDIR, for other non-regulars - -EINVAL */
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error = -EISDIR;
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if (S_ISDIR(inode->i_mode))
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goto dput_and_out;
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error = -EINVAL;
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return -EISDIR;
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if (!S_ISREG(inode->i_mode))
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goto dput_and_out;
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return -EINVAL;
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error = mnt_want_write(path.mnt);
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error = mnt_want_write(path->mnt);
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if (error)
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goto dput_and_out;
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goto out;
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error = inode_permission(inode, MAY_WRITE);
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if (error)
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@ -111,19 +100,34 @@ static long do_sys_truncate(const char __user *pathname, loff_t length)
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error = locks_verify_truncate(inode, NULL, length);
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if (!error)
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error = security_path_truncate(&path);
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error = security_path_truncate(path);
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if (!error)
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error = do_truncate(path.dentry, length, 0, NULL);
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error = do_truncate(path->dentry, length, 0, NULL);
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put_write_and_out:
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put_write_access(inode);
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mnt_drop_write_and_out:
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mnt_drop_write(path.mnt);
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dput_and_out:
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path_put(&path);
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mnt_drop_write(path->mnt);
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out:
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return error;
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}
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EXPORT_SYMBOL_GPL(vfs_truncate);
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static long do_sys_truncate(const char __user *pathname, loff_t length)
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{
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struct path path;
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int error;
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if (length < 0) /* sorry, but loff_t says... */
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return -EINVAL;
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error = user_path(pathname, &path);
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if (!error) {
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error = vfs_truncate(&path, length);
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path_put(&path);
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}
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return error;
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}
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SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
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{
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@ -1999,6 +1999,7 @@ struct filename {
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bool separate; /* should "name" be freed? */
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};
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extern long vfs_truncate(struct path *, loff_t);
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extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
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struct file *filp);
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extern int do_fallocate(struct file *file, int mode, loff_t offset,
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